| 1. |
- Koul, Anjila, et al.
(author)
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Identification of TP53 gene mutations in uterine corpus cancer with short follow-up
- 1997
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In: Gynecologic Oncology. - : Elsevier BV. - 1095-6859 .- 0090-8258. ; 67:3, s. 295-302
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Journal article (peer-reviewed)abstract
- The involvement of the TP53 tumor suppressor gene in uterine corpus cancer was investigated by single-stranded conformation polymorphism and sequence analysis of its exons 4 to 10. Mutations were found in 12 (18.5%) of 65 cases. Ten of these 12 were single-base substitutions (8 missense and 2 nonsense mutations), whereas 2 were frame-shifting mutations. TP53 gene mutations correlated significantly with advanced surgical stage of disease (P = 0.006) and unfavorable tumor histology types (P = 0.003), whereas the association to myometrial wall invasion did not reach statistical significance (P = 0.054). TP53 gene mutations also correlated significantly with allelic loss at TP53 locus (P = 0.024), absence of estrogen (P = 0.045) and progesterone receptors (P = 0.001), DNA nondiploidy (P = 0.002), and high S-phase fraction values (P = 0.002). Our results suggest that inactivation of the TP53 checkpoint function is associated with disease transition into a stage of rapid progression and spread.
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| 2. |
- Fioretos, Thoas, et al.
(author)
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Isochromosome 17q in blast crisis of chronic myeloid leukemia and in other hematologic malignancies is the result of clustered breakpoints in 17p11 and is not associated with coding TP53 mutations
- 1999
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In: Blood. - 1528-0020. ; 94:1, s. 225-232
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Journal article (peer-reviewed)abstract
- An isochromosome of the long arm of chromosome 17, i(17q), is the most frequent genetic abnormality observed during the disease progression of Philadelphia chromosome-positive chronic myeloid leukemia (CML), and has been described as the sole anomaly in various other hematologic malignancies. The i(17q) hence plays a presumably important pathogenetic role both in leukemia development and progression. This notwithstanding, the molecular consequences of this abnormality have not been investigated in detail. We have analyzed 21 hematologic malignancies (8 CML in blast crisis, 8 myelodysplastic syndromes [MDS], 2 acute myeloid leukemias, 2 chronic lymphocytic leukemias, and 1 acute lymphoblastic leukemia) with i(17q) by fluorescence in situ hybridization (FISH). Using a yeast artificial chromosome (YAC) contig, derived from the short arm of chromosome 17, all cases were shown to have a breakpoint in 17p. In 12 cases, the breaks occurred within the Smith-Magenis Syndrome (SMS) common deletion region in 17p11, a gene-rich region which is genetically unstable. In 10 of these 12 cases, we were able to further map the breakpoints to specific markers localized within a single YAC clone. Six other cases showed breakpoints located proximally to the SMS common deletion region, but still within 17p11, and yet another case had a breakpoint distal to this region. Furthermore, using chromosome 17 centromere-specific probes, it could be shown that the majority of the i(17q) chromosomes (11 of 15 investigated cases) were dicentric, ie, they contained two centromeres, strongly suggesting that i(17q) is formed through an intrachromosomal recombination event, and also implicating that the i(17q), in a formal sense, should be designated idic(17)(p11). Because i(17q) formation results in loss of 17p material, potentially uncovering the effect of a tumor suppressor on the remaining 17p, the occurrence of TP53 mutations was studied in 17 cases by sequencing the entire coding region. In 16 cases, no TP53 mutations were found, whereas one MDS displayed a homozygous deletion of TP53. Thus, our data suggest that there is no association between i(17q) and coding TP53 mutations, and that another tumor suppressor gene(s), located in proximity of the SMS common deletion region, or in a more distal location, is of pathogenetic importance in i(17q)-associated leukemia.
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| 3. |
- Hedenfalk, Ingrid, et al.
(author)
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Activated cell cycle checkpoints in epirubicin-treated breast cancer cells studied by BrdUrd-flow cytometry
- 1997
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In: Cytometry. - 0196-4763. ; 29:4, s. 321-327
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Journal article (peer-reviewed)abstract
- Genetic alterations, such as p53 mutations, may affect a tumour's response to chemotherapy. We have treated two human breast cancer cell lines that differ in p53 status with epirubicin in order to study if there are differences in cell cycle kinetic response. MCF-7 cells express wild-type p53, while SK-BR-3 cells express only a mutated form of p53. The transition of cells from one cell cycle stage to another was studied by a bromodeoxyuridine (BrdUrd)-flow cytometry (FCM) method. MCF-7 cells showed a block in the G1 phase after treatment with 50 nM epirubicin for 24 hours, in agreement with the actions of p53 at the G1 checkpoint. SK-BR-3 cells, on the other hand, progressed through the G1 checkpoint and were blocked in late S and G2 phases, presumably due to the activation of a later checkpoint. In addition, studies of the mRNA levels of p53 and its effector gene p21 revealed that although both cell lines expressed p53 mRNA, a marked difference in the mRNA levels of p21 was seen. A dramatic increase in the level of p21 mRNA was seen in epirubicin-treated MCF-7 cells, while no such increase was seen in SK-BR-3 cells.
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| 4. |
- Borg, Åke, et al.
(author)
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c-myc amplification is an independent prognostic factor in postmenopausal breast cancer
- 1992
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 51:5, s. 687-691
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Journal article (peer-reviewed)abstract
- The c-myc proto-oncogene was analyzed in 311 cases of primary breast cancer, in 8% of which it was found to be amplified, usually at moderately increased copy number (2-5 copies). The adjacent pvt gene was co-amplified with c-myc in all tumors analyzed. C-myc amplification was significantly correlated to a high S-phase fraction and to amplification of the c-erbB-2 proto-oncogene. Weak relationships were found between c-myc amplification and the presence of lymph-node metastasis, advanced stage, DNA non-diploidy and premenopausal status, but not tumor size, estrogen receptor or progesterone receptor status, or int-2 amplification. C-myc amplification, and especially a high gene copy number (greater than 5 copies), was significantly related to early recurrence and death in breast cancer, a relationship seen in both the lymph-node-negative and node-positive subcategories. A particularly strong correlation with poor clinical outcome was seen in postmenopausal patients (p greater than 0.0005), an association which persisted in multivariate survival analysis. We conclude that the activation of c-myc is indeed associated with rapidly growing and progressive breast cancer. Gene amplification, on the other hand, is relatively infrequent and occurs mostly at low copy number, implying that tumors are heterogeneous with respect to cell clones harboring c-myc amplification. An immunohistochemical assessment would more accurately illustrate the importance of c-myc activation in human breast cancer. However, the obvious instability of the c-myc transcript and translate suggests that c-myc is not a suitable prognostic marker for routine purposes.
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| 5. |
- Borg, Åke, et al.
(author)
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Chromosome I alterations in breast cancer : Allelic loss on Ip and Iq Is related to lymphogenic metastases and poor prognosis
- 1992
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In: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 5:4, s. 311-320
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Journal article (peer-reviewed)abstract
- The development of human breast cancer is characterized by a variety of genetic alterations, and cytogenetic analyses have documented the consistent involvement of both arms of chromosome I. In the present study, molecular markers detecting restriction fragment length polymorphisms were used in pairwise screening of normal and tumor DNA to determine the frequency of allelic imbalance in breast tumors. Loss of heterozygosity (LOH) in the polymorphic epithelial mucin (PEM or MUCI) gene at 1q21 was found in 16% of 89 informative (constitutionally heterozygous) cases, whereas gain in intensity of one allelic band was more frequent (37%), a total of 47% of cases manifesting either allelic loss or gain. Three additional tumors manifested a structural alteration. Allelic loss or gain in the PEM gene was not associated with other prognostic factors, e.g., tumor size, lymph node status, steroid receptors, DNA ploidy, S phase fraction, protooncogene amplification, histological type, or patient age. However, LOH in the PEM gene was significantly correlated with early disease recurrence (P = 0.006). LOH on 1p was found in 27% of 117 informative cases, using probes for either DIS57 or DIZ2 located at 1p33‐p35 and 1p36, respectively. Somatic allelic imbalance on 1p and 1q seemed to be independent events and not the effect of loss of a whole chromosome 1. LOH on 1 p was significantly correlated to the presence of lymph node metastasis, to larger tumor size, and to DNA nondiploidy, but no correlation was found to disease outcome at this limited duration of follow‐up (median 29 months). ©1992 Wiley‐Liss, Inc.
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| 6. |
- Borg, Åke, et al.
(author)
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ERBB2 amplification in breast cancer with a high rate of proliferation
- 1991
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In: Oncogene. - 1476-5594. ; 6:1, s. 137-143
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Journal article (peer-reviewed)abstract
- The ERBB2 proto-oncogene was studied in 539 invasive primary breast tumors and was found amplified (2- greater than 30 copies) in 19%. Amplification was correlated to most known risk factors, including; large tumor size, lymph node positivity and many tumor involved nodes, advanced stage, low patient age (less than 40 years), non-diploidy and hypertetraploidy, and most significantly (P less than 0.00001) to the absence of steroid receptors and to a high rate of proliferation (flow cytometric determined S phase fraction). ERBB2 amplification was strongly associated (P less than 0.0001) with early recurrence and death in breast cancer among node-positive patients. This connection did not, however, remain in multivariate analyses. No correlations to clinical outcome were seen among node-negative patients. Similarly, non-diploid, but not diploid, amplified tumors were particularly aggressive. Furthermore, ERBB2 amplification was associated with a high rate of proliferation and poor prognosis in steroid receptor positive, but not receptor negative tumors. In progesterone receptor positive breast cancer, amplification was an independent and with node status equally powerful (P less than 0.0001) predictor of poor survival. It is concluded that ERBB2 activity is related to an increased tumor growth rate but not directly to metastasizing ability. Its clinical relevance as a prognostic factor may be in selecting a high risk subgroup of breast cancer, in general considered as being of good prognosis.
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| 7. |
- Borg, Åke, et al.
(author)
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ERBB2 amplification is associated with tamoxifen resistance in steroid-receptor positive breast cancer
- 1994
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In: Cancer Letters. - : Elsevier BV. - 1872-7980 .- 0304-3835. ; 81:2, s. 137-144
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Journal article (peer-reviewed)abstract
- Amplification and overexpression of the ERBB2 (HER-2/neu) oncogene has been implicated as contributing to the development of human breast cancer, and as a predictor of poor survival. In the present non-randomized study of 871 primary invasive breast tumours, ERBB2 activation was significantly correlated to a shorter disease-free and overall survival in the subgroup of patients receiving adjuvant tamoxifen therapy, but not in the untreated group. Further subcategorization demonstrated the relationship to poor prognosis to be confined to lymph node positive and steroid receptor-positive tumours. We suggest that steroid receptor and ERBB2-positive breast tumours are resistant to tamoxifen therapy and, supported by experimental evidence showing an oestrogen receptor dependent up-regulation of ERBB2 expression upon tamoxifen administration, possibly even growth stimulated by the drug.
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| 8. |
- Borg, Åke, et al.
(author)
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Novel germline p16 mutation in familial malignant melanoma in southern Sweden
- 1996
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In: Cancer Research. - 0008-5472. ; 56:11, s. 500-2497
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Journal article (peer-reviewed)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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| 9. |
- Bratt, O, et al.
(author)
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CAG repeat length in the androgen receptor gene is related to age at diagnosis of prostate cancer and response to endocrine therapy, but not to prostate cancer risk
- 1999
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In: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 81:4, s. 6-672
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Journal article (peer-reviewed)abstract
- The length of the polymorphic CAG repeat in the N-terminal of the androgen receptor (AR) gene is inversely correlated with the transactivation function of the AR. Some studies have indicated that short CAG repeats are related to higher risk of prostate cancer. We performed a case-control study to investigate relations between CAG repeat length and prostate cancer risk, tumour grade, tumour stage, age at diagnosis and response to endocrine therapy. The study included 190 AR alleles from prostate cancer patients and 186 AR alleles from female control subjects. All were whites from southern Sweden. The frequency distribution of CAG repeat length was strikingly similar for cases and controls, and no significant correlation between CAG repeat length and prostate cancer risk was detected. However, for men with non-hereditary prostate cancer (n = 160), shorter CAG repeats correlated with younger age at diagnosis (P = 0.03). There were also trends toward associations between short CAG repeats and high grade (P = 0.07) and high stage (P = 0.07) disease. Furthermore, we found that patients with long CAG repeats responded better to endocrine therapy, even after adjusting for pretreatment level of prostate-specific antigen and tumour grade and stage (P = 0.05). We conclude that short CAG repeats in the AR gene correlate with young age at diagnosis of prostate cancer, but not with higher risk of the disease. Selection of patients with early onset prostate cancer in case-control studies could therefore lead to an over-estimation of the risk of prostate cancer for men with short CAG repeats. An association between long CAG repeats and good response to endocrine therapy was also found, but the mechanism and clinical relevance are unclear.
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| 10. |
- Ewers, Sven-Börje, et al.
(author)
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Flow cytometry DNA analysis and prediction of loco-regional recurrences after mastectomy in breast cancer
- 1992
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In: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 31:7, s. 733-740
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Journal article (peer-reviewed)abstract
- The study concerns whether DNA flow cytometry and estrogen receptor analysis might help predict which breast cancer patients, particularly node-positive ones, were at the greatest risk of developing loco-regional recurrence (LRR). Such patients would best benefit from postoperative radiotherapy following modified radical mastectomy and axillary lymph node dissection. After this type of surgery, 506 patients were followed up for a median time of nearly 5 years. Among the 235 patients given postoperative radiotherapy, the loco-regional control rate was 100% in N0 cases (n = 93), 94% in cases with 1-3 positive nodes (n = 90), 93% in cases with 4-9 positive nodes (n = 43), and 67% in cases with 10 or more positive nodes (n = 9). Among the 271 non-irradiated patients, the corresponding figures for loco-regional control were 91% in N0 cases (n = 141), 71% in cases with 1-3 positive nodes (n = 84), 65% in cases with 4-9 positive nodes (n = 31), and 67% in cases with 10 or more positive nodes (n = 15). Ploidy status, level of S-phase fraction, estrogen receptor content, and primary tumor size did not, in the present material, yield significant additional information with regard to the risk of LRR in the different nodal subgroups, a finding confirmed in multivariate analysis where the only significant predictor of LRR was the number of positive nodes (p = 0.01). Adjuvant tamoxifen treatment could not replace postoperative radiotherapy for achieving loco-regional tumor control, the overall rate of which was 81% among patients treated with tamoxifen only (n = 117), as compared with 98% among those also treated with radiotherapy (n = 54) (p = 0.003).
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