| 1. |
- Andersson, Torbjörn, et al.
(författare)
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Effects of Interferon on Tumor Tissue Content in Liver Metastases of Human Carcinoid Tumors
- 1990
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; :50, s. 3413-3415
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Tidskriftsartikel (refereegranskat)abstract
- In 21 patients ultrasound-guided cutting biopsies, from carcinoid metastases of the liver, were taken before and after therapy with α-interferon. Each biopsy was examined under light microscopy and the amount of tumor tissue and connective tissue was quantified and then correlated to objective response to interferon therapy. A significant reduction of the amount of tumor tissue, in spite of unaltered metastatic size and a corresponding increase in connective tissue, was seen after interferon therapy. A more pronounced reduction of tumor tissue occurred after long-term interferon therapy. A positive correlation between objective therapy response and tumor tissue reduction was also present. Patients responding poorly, or not at all, to therapy did not show any significant decrease in tumor tissue. Since treatment with immune response modifiers is expected to increase in the near future, it is important to choose the right investigations for therapy monitoring, and since all patients in this investigation had unchanged tumor size on repeated radiological examinations, it is obvious that microscopic examination of core biopsies is a better method for evaluating effects of long-term therapy than tumor size measurement with radiological techniques. Further, the results may indicate that interferon exerts a cytotoxic effect on carcinoid tumor cells in vivo.
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| 2. |
- Aust, Gabriela, et al.
(författare)
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CD97: A dedifferentiation marker in human thyroid carcinomas
- 1997
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 57:9, s. 1798-1806
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Tidskriftsartikel (refereegranskat)abstract
- CD97 is a dimeric glycoprotein of Mr 75,000-85,000 and 28,000 belonging to a novel subfamily of seven-span transmembrane region leukocyte cell surface molecules. It is expressed abundantly in cells of hematopoietic origin. This is the first report demonstrating the expression of CD97 outside the hematopoetic system. CD97 was studied in normal human and neoplastic follicular epithelium of the thyroid and anaplastic (n = 3) and papillary (n = 1) thyroid carcinoma cell lines. In normal thyroid tissue (n = 11), no immunoreactivity of CD97 could be found, whereas in differentiated thyroid carcinomas (n = 10), CD97 expression was either lacking or low. Eleven of 12 undifferentiated anaplastic carcinomas revealed high CD97 presentation. CD97 was absent or only weakly present in patients with postoperative T1 tumors but increased greatly with the progression to postoperative T4 tumors. CD97 is clearly present in thyroid carcinoma cell lines but only at a very low level in normal human thyrocytes. Quantitation of CD97 cell surface expression levels revealed that C 643 and SW 1736 cells showed a two to four times higher specific antibody-binding capacity than did 8505 C and HTh 74 cells and a nearly 20 times higher specific antibody-binding capacity than normal thyrocytes. Phorbol 12-myristate 13-acetate treatment progressively caused a decrease of CD97 antigen expression in all cell lines to about 30% of their initial levels after 48 h. Immunohistochemical staining of SW 1736 cells revealed that CD97 is located in most of the cell compartments and suggested a CD97 internalization process after phorbol 12-myristate 13-acetate treatment. Semiquantitative reverse transcription-PCR showed a correlation of CD97 mRNA and cell surface CD97 expression level in the cell lines. SW 1736, HTh 74, and 8505 C cells apparently expressed CD97 with alternative glycosylation compared to peripheral lymphocytes, whereas most of the CD97 antigen presented on thyrocytes and C 643 cells had glycosylation sites resembling those of lymphocytes. The data suggest that CD97 expression may be a sensitive marker of dedifferentiation and of lymph node involvement in human thyroid tumors.
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| 3. |
- Baranov, Vladimir, et al.
(författare)
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Expression of carcinoembryonic antigen and nonspecific cross-reacting 50-kDa antigen in human normal and cancerous colon mucosa : comparative ultrastructural study with monoclonal antibodies
- 1994
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 54:12, s. 3305-3314
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Tidskriftsartikel (refereegranskat)abstract
- The precise localization of carcinoembryonic antigen (CEA) and non-specific cross-reacting 50-kDa antigen (NCA 50) in normal colon mucosa and colon adenocarcinoma was investigated by using an indirect immunoperoxidase electron microscopic technique with specific monoclonal antibodies. In normal adult colon both antigens were localized to microvesicles and filaments of the "fuzzy coat" on the apical surface of the epithelial cells. In addition, NCA 50 was found in the narrow spaces between adjoining microvilli. Mature columnar cells at the free luminal surface contained most of the antigen positive material. CEA and NCA 50 were also detected as intracellular components of goblet cells. In multilayered tumor glands, the cell surface expression of the antigens was dependent on the position of the tumor cell in the gland. The neoplastic cells showed either a predominant apical labeling or a positive staining of almost the entire cell surface. Some of the neoplastic cells contained CEA in so-called "intracellular lumina." In contrast to normal colon epithelial cells most tumor cells synthesized NCA 50 actively. In normal colonic mucosa, unlike in cancerous tissue, CEA and NCA 50 appear to be released via vesicles formed from the microvillous membrane of mature columnar cells. These results are consistent with the hypothesis that CEA and NCA play a role in the nonspecific defense against microorganisms in the large intestine.
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| 4. |
- Brodin, G, et al.
(författare)
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Increased smad expression and activation are associated with apoptosis in normal and malignant prostate after castration.
- 1999
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Ingår i: Cancer research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 59:11, s. 2731-8
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor (TGF)-beta1 is induced in the prostate after castration and has been implicated in apoptosis of epithelial cells during involution. TGF-beta1-mediated receptor activation induces phosphorylation of Smad2 and Smad3, which form complexes with Smad4, that translocate to the nucleus to regulate transcription of target genes. Smad6 and Smad7 antagonize the action of signal-transducing Smads. We have examined the immunohistochemical expression of different Smad molecules in the epithelium of rat ventral prostate before and after castration, in androgen-sensitive Dunning R3327 PAP prostatic tumor cells from untreated and castrated rats, and after treatment with estrogen. In the ventral prostate, a significant increase of phosphorylated Smad2 (P-Smad2) was observed after castration. In prostatic tumor cells we observed an increased expression of Smad2 and P-Smad2 after treatment. The levels of Smad3 and, in particular, Smad4 were enhanced in the normal ventral prostate, as well as in the tumors after castration. Interestingly, Smad6 and Smad7 expression was also up-regulated in cells with increased Smad2 activation. The staining for Smad2, P-Smad2, Smad3, Smad4, and Smad7 was nuclear in some cells and was present in areas with a large number of apoptotic cells identified by various morphological criteria, formation of apoptotic bodies and, in adjacent sections, by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Our results suggest that the signal transduction pathway for TGF-beta, leading to apoptosis, is activated in the normal prostate after castration and in the tumor model after castration, without or with estrogen treatment.
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| 5. |
- Chaudhry, Arvind, et al.
(författare)
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Different splice variants of CD44 are expressed in gastrinomas but not in other subtypes of endocrine pancreatic tumors
- 1994
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 54:4, s. 981-986
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Tidskriftsartikel (refereegranskat)abstract
- Endocrine pancreatic tumors are neuroendocrine neoplasms with malignant potential and give rise to varied clinical syndromes due to excessive secretion of multiple hormones. In this study 22 endocrine pancreatic tumors and 11 carcinoid tumors were examined for the expression of CD44 using a monoclonal antibody. CD44 gene activity of 11 endocrine pancreatic tumor tissues and five carcinoid tumor tissues was also studied by amplifying messenger RNA with the polymerase chain reaction followed by electrophoresis and blot hybridization. Strong immunoreactivity was detected on all gastrinomas examined (P < 0.001), and in two non-functioning endocrine pancreatic tumors. Such immunoreactivity was not observed in other subtypes of endocrine pancreatic tumors. In the normal human pancreas, the acinar portion and ductal epithelial cells stained strongly positive but pancreatic islet cells did not show any significant immunostaining. Furthermore, in endocrine pancreatic tumors with metastatic disease, CD44-positive tumors had a tendency to metastasize to lymph nodes (P = 0.005), as compared with CD44-negative tumors which were locally invasive or metastasized to the liver. Although, in this limited material and short follow-up, we were not able to show any statistical significance, patients with CD44-negative endocrine pancreatic tumors had prolonged survival time compared with patients with CD44-positive tumors (73% versus 59% at 5 years; P = 0.7). Of 10 carcinoid tumors examined, all three foregut carcinoids and one midgut carcinoid stained strongly positive, whereas all other midgut carcinoids were negative. Analysis of CD44 splice variants showed that in all five gastrinomas there was overproduction of alternatively spliced larger molecular variants as compared with other types of endocrine pancreatic tumors and carcinoid tumors. The band pattern from one case of carcinoid tumor with a fulminant clinical course was similar to that of gastrinomas, whereas other carcinoid tumors expressed the epithelial form of CD44. The earlier identified splice variants which confer metastatic behavior on a pancreatic tumor cell line were not expressed in neuroendocrine tumors. Our data indicate that CD44 expression in endocrine pancreatic tumors correlates with the ability to give rise to lymph node metastases and may play a vital role in determining the fate of metastasizing cells. Moreover, because gastrin is not detectable in the normal human pancreas, the pancreatic ductal cell positivity for CD44 strengthened the ductal origin concept of gastrinomas. The band pattern of CD44 splice variants suggests that the previously described splice variants conferring metastatic behavior do not accompany metastatic activity of neuroendocrine tumors.
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| 6. |
- Frisch, Morten, et al.
(författare)
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Variants of squamous cell carcinoma of the anal canal and perianal skin and their relation to human papillomaviruses
- 1999
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 59:3, s. 753-757
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Tidskriftsartikel (refereegranskat)abstract
- High-risk types of human papillomaviruses (hrHPVs) may be a necessary cause in cervical cancer and in some subtype of anal, vulvar, and penile cancers. Large studies aimed at characterizing hrHPV-associated and non-hrHPV-associated subtypes of anal carcinomas are, however, lacking. We searched for human papillomavirus type 16 and 13 other hrHPVs in tumor tissue by PCR and performed a systematic histological evaluation of specimens from 386 patients with anal cancer (86% invasive; 302 women and 84 men). Cancers in women and homosexual men were more often hrHPV positive (P < 0.01) and located in the anal canal (P < or = 0.01) than were cancers in heterosexual men. In both women and men, anal canal cancers contained hrHPV clearly more often than did perianal skin cancers, and increasing hrHPV positivity was seen with higher localization in the anal canal. Indeed, 95 and 83% of cancers involving the anal canal in women and men, respectively, were hrHPV positive versus 80 and 28% of perianal skin cancers (P-trend < 0.001). Basaloid feature, adjacent anal intraepithelial neoplasia, poor or absent keratinization, and a predominance of small or medium neoplastic cells were all strongly positively associated with hrHPV status. Like cancer of the uterine cervix, the development of cancer of the anal canal may require infection with hrHPV, whereas a dual etiology of perianal skin cancers bears parallels to vulvar and penile cancers.
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| 7. |
- Frängsmyr, Lars, et al.
(författare)
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Cell- and region-specific expression of biliary glycoprotein and its messenger RNA in normal human colonic mucosa
- 1995
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 55:14, s. 2963-2967
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Tidskriftsartikel (refereegranskat)abstract
- The localization of biliary glycoprotein (BGP) and its mRNA in normal colonic mucosa was studied by immunohistochemistry and in situ hybridization. BGP mRNA was confined to columnar epithelial cells and expressed abundantly in the superficial mature cells and at low levels in differentiating cells in the upper crypts. Epithelial expression of BGP coincided with that of BGP mRNA. Ultrastructurally, BGP was localized to microfilaments of the fuzzy coat of the columnar cells at the luminal surface and the upper crypts. Additionally, BGP was found in cryptal caveolated cells. The results are consistent with primary transcriptional regulation of BGP production and suggest that BGP synthesis is controlled by the degree of cytodifferentiation. The fuzzy-coat localization of BGP implies a role in nonspecific defense mechanisms against pathogens.
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| 8. |
- Fulda, S., et al.
(författare)
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Betulinic acid triggers CD95 (APO-1/Fas)- and p53-independent apoptosis via activation of caspases in neuroectodermal tumors
- 1997
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 57:21, s. 4956-4964
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Tidskriftsartikel (refereegranskat)abstract
- Betulinic acid CBA), a melanoma-specific cytotoxic agent, induced apoptosis in neuroectodermal tumors, such as neuroblastoma, medulloblastoma, and Ewing's sarcoma, representing the most common solid tumors of childhood. BA triggered an apoptosis pathway different from the one previously identified for standard chemotherapeutic drugs. BA-induced apoptosis was independent of CD95-ligand/receptor interaction and accumulation of wild-type p53 protein, but it critically depended on activation of caspases (interleukin 1 beta-converting enzyme/Ced-3-like proteases), FLICE/MACH (caspase-8), considered to be an upstream protease in the caspase cascade, and the downstream caspase CPP32/YAMA/Apopain (caspase-3) were activated, resulting in cleavage of the prototype substrate of caspases PARP. The broad-spectrum peptide inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, which blocked cleavage of FLICE and PARP, also completely abrogated BA-triggered apoptosis. Cleavage of caspases was preceded by disturbance of mitochondrial membrane potential and by generation of reactive oxygen species. Overexpression of Bcl-2 and Bcl-x(L) conferred resistance to BA at the level of mitochondrial dysfunction, protease activation, and nuclear fragmentation. This suggested that mitochondrial alterations were involved in BA-induced activation of caspases. Furthermore, pax and Bcl-x(s), two death-promoting proteins of the Bcl-2 family, were up-regulated following BA treatment. Most importantly, neuroblastoma cells resistant to CD95- and doxorubicin-mediated apoptosis were sensitive to treatment with BA, suggesting that BA may bypass some forms of drug resistance. Because BA exhibited significant antitumor activity on patients' derived neuroblastoma cells ex vivo, BA may be a promising new agent for the treatment of neuroectodermal tumors in vivo.
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| 9. |
- Hessman, Ola, et al.
(författare)
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Mutation of the Multiple Endocrine Neoplasia Type 1 gene in nonfamilial, malignant tumors of the endocrine pancreas
- 1998
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 58:3, s. 377-379
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Tidskriftsartikel (refereegranskat)abstract
- Endocrine pancreatic tumors are rare neoplasms that occur sporadically or as part of a multiple endocrine neoplasia type 1 (MEN1) syndrome. Germ-line mutations of the MEN1 gene, located at 11q13, have been demonstrated in MEN1 kindreds, and loss of heterozygosity (LOH) on 11q13 together with somatic MEN1 mutations have been detected in 20% of nonfamilial parathyroid tumors. Here, we examine 11 non-MEN1 malignant tumors of the endocrine pancreas, 9 nonfunctioning tumors, and 2 glucagonomas. LOH of at least one informative locus on 11q13 was found in 70% of the tumors. Three tumors displayed somatic mutations of the MEN1 gene together with LOH on 11q13, whereas the corresponding germ-line DNA was normal. These findings support the hypothesis that MEN1 gene mutations contribute to the tumorigenesis of nonfamilial, malignant endocrine pancreatic tumors.
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| 10. |
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| 11. |
- Johansson, A., et al.
(författare)
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Epitope specificity of the monoclonal anticytokeratin antibody TS1
- 1999
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 59:1, s. 48-51
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Tidskriftsartikel (refereegranskat)abstract
- Due to their abundance in epithelial cells and deposition in necrotic regions intratumorally, cytokeratins (CKs) have been established as valuable targets for both radioimmunolocalization and radioimmunotherapy. The target epitope for the monoclonal anti-CK8 antibody, TS1, used for both experimental radioimmunolocalization and radioimmunotherapy, was determined by means of synthesis of 96 overlapping peptides that covered the entire CK8 molecule. A highly conserved peptide sequence, spanning amino acids (aa) 343-357 and covering the discontinuous epitope in the helical 2B domain, was identified. The epitope retains its helical structure, as shown with circular dichroism spectroscopy, although the length of the peptide (ie., >20 aa) is crucial for maintenance of immunoreactivity. To determine which aa residues are crucial for binding to the monoclonal antibody, alanine scanning was performed on a 26-mer covering aa 340-365, with the sequence QRGELAIKDANAKLSELEAALQRAKQ. The 26 modified peptides were evaluated using ELISA and BIAcore technology. The uniqueness of this epitope has been established by data base sequence comparisons.
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| 12. |
- Lundin, Anna-Carin, et al.
(författare)
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Association of breast cancer progression with a vitamin D receptor gene polymorphism
- 1999
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 59:10, s. 2332-2334
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Tidskriftsartikel (refereegranskat)abstract
- The vitamin D3 receptor gene (VDR) contains a TaqI RFLP that is associated with increased VDR mRNA stability, increased serum levels of 1α,25-dihydroxyvitamin D3 (1,25-D3), and decreased risk for prostate cancer. Determination of the TaqI genotype, in a group of young women with breast cancer (n = 111; age, <37 years) and a control population (n = 130), revealed no overall association to risk for breast cancer. However, patients without TaqI site (TT genotype) showed a significantly increased risk for lymph node metastasis (relative risk, 1.8, 95% confidence interval, 1.3- 2.6). Furthermore, a tendency toward an increased survival was found among estrogen receptor-positive, tamoxifen-treated patients who were homozygous for the TaqI site (P = 0.075). We conclude that polymorphism in the VDR gene may influence tumor progression and tamoxifen treatment response in early- onset breast carcinomas.
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| 13. |
- Nap, M, et al.
(författare)
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Specificity and affinity of monoclonal antibodies against carcinoembryonic antigen.
- 1992
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 52:8, s. 2329-39
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Tidskriftsartikel (refereegranskat)abstract
- The binding specificities of 52 well-characterized monoclonal antibodies (Mabs) against carcinoembryonic antigen (CEA) from 12 different research groups were studied by immunohistochemistry and immuno flow cytometry. In addition, the binding constant for the interaction between Mab and CEA was determined by a solution-phase assay. Cryostat sections of colon carcinoma and normal colon, stomach, liver, pancreas, and spleen were studied by immunohistochemistry. Peripheral blood granulocytes, monocytes, and lymphocytes were assayed by immuno flow cytometry. The Mabs used here have previously been classified into five essentially nonoverlapping epitope groups (GOLD 1-5) (Cancer Res., 49: 4852-4858, 1989). Most Mabs cross-reacted with different normal tissues, ranging from highly cross-reactive Mabs (positive reaction with 8 of 9 discriminating tissues) to relatively specific Mabs (positive reaction with 1 of 9 discriminating tissues). Five Mabs (10%) were specific, reacting only with colon carcinoma, normal colon mucosa, and normal gastric foveola. There was a correlation between epitope group and binding specificity. Mabs with a high degree of CEA specificity almost exclusively belonged to epitope groups 1, 2, and 3, while highly cross-reactive Mabs belonged to epitope groups 4 and 5. There was no correlation between antibody specificity and affinity for CEA. Specific Mabs with high as well as low affinity were found.
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| 14. |
- Spyrou, Giannis, et al.
(författare)
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Selenite and selenate inhibit human lymphocyte growth via different mechanisms
- 1996
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Ingår i: Cancer Research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 56:19, s. 4407-4412
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Tidskriftsartikel (refereegranskat)abstract
- Selenium compounds like selenite and selenate have strong inhibitory effects, particularly on mammalian tumor cell growth by unknown mechanisms. We found that the addition of sodium selenite and sodium selenate inhibited the growth of human 3B6 and BL41 lymphocytes. Selenite was more potent because 10 microM selenite produced a growth inhibitory effect similar to that of 250 microM selenate. The mechanism of action of selenite and selenate appears to be different. 3B6 and BL41 cells treated with selenite accumulated in the S-phase; however, selenate caused an accumulation of cells in G2. Selenite-mediated growth inhibition was irreversible, although the effects of selenate could be reversed. Selenite, in contrast to selenate, is efficiently reduced by the thioredoxin system (thioredoxin, thioredoxin reductase, and NADPH). At concentrations required to observe a similar effect on cell growth, the activity of thioredoxin reductase, recently shown to be a selenoprotein, increased in selenite-treated cells and decreased in selenate-treated cells. Ribonucleotide reductase activity was inhibited in an in vitro assay by selenite and selenodiglutathione but not by selenate. These results show that selenite and selenate use different mechanisms to inhibit cell growth.
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| 15. |
- Uhrbom, Lene, et al.
(författare)
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Induction of brain tumors in mice using a recombinant PDGF B retrovirus
- 1998
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 58:23, s. 5275-5279
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Tidskriftsartikel (refereegranskat)abstract
- In existing mouse models for malignant brain tumors, genes with no proven pathogenical relevance for humans have been used. Coexpression of platelet-derived growth factor (PDGF) and PDGF receptors suggests an autocrine mechanism of growth factor stimulation in the development of brain tumors in man. A murine retrovirus coding for the PDGF B-chain was, therefore, used to induce brain tumors in mice. Of 35 mice who received injections, 15 developed brain tumors of oligo- or monoclonal origin. They coexpressed PDGF B-chain and alpha-receptor mRNA, as expected, from an autocrine mechanism of transformation. Most tumors displayed characteristics of glioblastoma multiforme or of a primitive neuroectodermal tumor, and the consistent expression of nestin suggested that they were all derived from an immature neuroglial progenitor. The results show that an autocrine mechanism of transformation may be an initial or early event in neuro-oncogenesis. The present model provides an ideal system for studies of genetic mechanisms involved in the development of brain tumors.
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| 16. |
- Ullén, A, et al.
(författare)
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Use of anticytokeratin monoclonal anti-idiotypic antibodies to improve tumor : nontumor ratio in experimental radioimmunolocalization.
- 1995
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 55:23 Suppl, s. 5868s-5873s
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Tidskriftsartikel (refereegranskat)abstract
- A syngeneic, high-affinity, anti-idiotypic monoclonal antibody (MAb; alpha TS1) raised against an anticytokeratin monoclonal antibody (TS1) was evaluated as a second antibody to promote the rapid clearance of radiolabeled TS1 from the blood during experimental radioimmunolocalization. By using a novel biosensor technology (BIAcore), association rate dissociation rate, and affinity constants between the idiotype and the anti-idiotype could be determined. The in vivo results in nude mice carrying HeLa Hep 2 tumors demonstrate the possibility of selectively regulating the amount of the idiotypic 125I-labeled circulating MAb by in vivo injection of this high-affinity, anti-idiotypic antibody. Injection of the anti-idiotype in a molar ratio of 0.75 to the idiotype cleared the blood pool from circulating radiolabeled idiotype within 24 h, with a concomitant rapid excretion of 125I in urine. The total amount of remaining radioactivity in the animals decreased to 15-20% during these 24 h, with the tumors still retaining 60-65% of their initial radioactivity. This approach, using syngeneic primary and secondary MAbs with minimized immunogenicity, significantly improves the tumor:nontumor ratio, thus improving efficiency in experimental radioimmunolocalization and radioimmunotherapy, leaving the endogenous antibody repertoire of the host unaffected.
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| 17. |
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| 18. |
- Williams, Cecilia, 1969-, et al.
(författare)
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Clones of normal keratinocytes and a variety of simultaneously present epidermal neoplastic lesions contain a multitude of p53 gene mutations in a xeroderma pigmentosum patient.
- 1998
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 58:11
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Tidskriftsartikel (refereegranskat)abstract
- A patient with xeroderma pigmentosum group C was extensively examined for mutations in the p53 gene in normal skin exposed to varying degrees of sunlight and in excisional biopsies of basal cell cancer, squamous cell cancer, and squamous cell dysplasia. Seventy-three samples were analyzed by microdissection of small cell clusters, followed by PCR and direct DNA sequencing. In skin taken from areas that most likely had never been exposed to the sun, no mutations were found. However, in skin exposed to the sun, we observed a multitude of mutations in the p53 gene. UV light-induced mutations were found in all types of lesions, as well as in clusters of morphologically normal epidermal cells. Twenty-nine distinct mutations were found in exons 5-8, all missense or nonsense, of which 27 (93%) were UV-specific C --> T or CC --> TT transitions at dipyrimidine sites of the nontranscribed strand. Two types of normal skin areas containing p53 mutations were observed: areas that stain strongly with p53 antibody (p53 patches) and those that do not stain. Because no silent or intron mutations were found in these cell clusters, the alterations in the p53 gene of morphologically normal cells are likely to have resulted in a selective growth advantage. The poor correlation between mutations and morphological phenotypes demonstrates that p53 mutations alone do not determine the phenotypes observed.
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| 19. |
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| 20. |
- Borg, A, et al.
(författare)
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HER-2/neu amplification predicts poor survival in node-positive breast cancer
- 1990
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Ingår i: Cancer Research. - 0008-5472. ; 50:14, s. 7-4332
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Tidskriftsartikel (refereegranskat)abstract
- HER-2/neu protooncogene amplification and protein expression were analyzed with slot blot and Western blot techniques, respectively, in more than 300 invasive primary breast tumors of all stages. Amplification (2- greater than 30 copies) was found in 17% of these tumors and high expression was seen in 19%. There was a striking coincidence between gene amplification and high expression. Tumors associated with many involved axillary lymph nodes or with Stage IV disease were more often HER-2/neu amplified or overexpressed. Furthermore, gene alteration was strongly correlated with the absence of steroid receptors and with larger tumor size. High expression without gene amplification was seen in a minor subset of tumors of less aggressive character. Neither amplification nor overexpression was correlated with disease outcome for patients with negative axillary lymph nodes. For node-positive patients, however, HER-2/neu amplification was a significant predictor of early relapse and death (median follow-up = 45 months), and a similar trend, although not significant, existed for high gene expression. Multivariate analyses indicated that HER-2/neu alterations were not independent predictors of patient outcome.
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| 21. |
- Borg, Ake, et al.
(författare)
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The Retinoblastoma Gene in Breast Cancer : Allele Loss Is Not Correlated with Loss of Gene Protein Expression
- 1992
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Ingår i: Cancer Research. - 0008-5472. ; 52:10, s. 2991-2994
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Tidskriftsartikel (refereegranskat)abstract
- The significance of the retinoblastoma gene (RB) in the development of human breast cancer remains unclear. In the present study, loss of heterozygosity (LOH) in RB was found in 26% of 90 informative primary breast tumors and was correlated to DNA nondiploidy, a high S-phase fraction, and LOH at chromosome 17pl33. However, allele loss was not associated with loss of RB protein (pRB) expression. Low to absent levels of pRB were found in 15% of 73 immunoblot analyzed tumors, most of which manifested retained heterozygosity in RB. Conversely, tumors exhibiting LOH showed often high pRB expression. Our data suggest that RB may be Involved in the pathogenesis of some breast tumors, as evidenced by the absence of pRB, but that this alteration is acquired by mechanisms other than the unmasking of a recessive mutation by allele loss. LOH in RB may be merely a stochastic event in the unstable genome of aneuploid, rapidly proliferating cells or, alternatively, reflect the presence of an adjacent tumor suppressor gene.
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| 22. |
- Borg, Åke, et al.
(författare)
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Novel germline p16 mutation in familial malignant melanoma in southern Sweden
- 1996
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Ingår i: Cancer Research. - 0008-5472. ; 56:11, s. 500-2497
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Tidskriftsartikel (refereegranskat)abstract
- The p16 (CDKN2/MTS1/INK4a) malignant melanoma susceptibility gene was analyzed in 10 melanoma kindreds from southern Sweden using single-stranded conformation polymorphism analysis of all three exons and flanking intron regions followed by sequence analysis. A novel germline mutation, constituting an in-frame 3-bp duplication at nucleotide 332 in exon 2, was identified in two families (Lund M2 and M9). The mutation results in an insertion of Arg at codon 105, which interrupts the last of the four ankyrin repeats of the p16 protein, motifs which have been demonstrated as important in binding and inhibiting the activity of cyclin D-dependent kinases 4 and 6 in cell cycle G1 phase regulation. All five tested individuals of Lund M2 and M9 affected by melanoma were mutation carriers, as were five melanoma-free individuals. Other malignancies observed in gene carriers or obligate carriers included cervical, breast, and pancreatic carcinomas and a non-Hodgkin's lymphoma. Analysis of microsatellite markers adjacent to the p16 gene at chromosomal region 9p21 revealed that both families share a common haplotype, in keeping with a common ancestor.
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| 23. |
- Brabant, G, et al.
(författare)
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E-cadherin: a differentiation marker in thyroid malignancies.
- 1993
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Ingår i: Cancer research. - 0008-5472. ; 53:20, s. 4987-93
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Tidskriftsartikel (refereegranskat)abstract
- Loss of E-cadherin (uvomorulin), a Ca(2+)-dependent cell adhesion molecule required for normal epithelial function, has been attributed a pathogenetic role in tumor invasion. The expression of E-cadherin was studied in normal and neoplastic follicular epithelium of the human thyroid by Northern blot analysis and immunofluorescence on frozen tissue sections. In the normal thyroid (n = 10) and in benign thyroid disorders (n = 21; toxic diffuse goitre; multinodular goitre; follicular adenomas), E-cadherin mRNA levels were equally high and the follicles were generally stained, mainly along the lateral surface of the epithelial cells, by the anti-E-cadherin monoclonal antibody. In anaplastic thyroid carcinomas (n = 6) E-cadherin expression was very low or lacking. In papillary carcinomas (n = 23), E-cadherin mRNA levels varied from nearly normal to highly reduced, which roughly correlated with the overall immunofluorescence intensity. However, the immunostaining also revealed a heterogeneous "all-or-nothing" expression of E-cadherin among adjacent cells in the same tumor. In the follicular carcinomas (n = 9), E-cadherin mRNA levels were in general rather high but the immunostaining varied considerably. A few papillary and follicular tumors lacked immunoreactive E-cadherin in spite of high mRNA levels. In oxyphilic (Hürthle) cell tumors, comprising both adenomas (n = 4) and carcinomas (n = 2), E-cadherin immunoreactivity was reduced and distributed intracellularly rather than at the cell surface. The expression of E-cadherin in relapsing thyroid carcinomas and in tumors with metastatic spreading was, irrespective of the histiotype, low or lacking. Sequential Northern analysis revealed a close correlation between the expression levels of E-cadherin and the thyrotropin receptor. Together, the data suggest that in human thyroid malignancies both gene expression and posttranscriptional control of E-cadherin may be impaired.
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