| 1. |
- Borg, Åke, et al.
(författare)
-
Novel germline p16 mutation in familial malignant melanoma in southern Sweden
- 1996
-
Ingår i: Cancer Research. - 0008-5472. ; 56:11, s. 500-2497
-
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.
|
|
| 2. |
- Hakansson, Sara, et al.
(författare)
-
Moderate frequency of BRCA1 and BRCA2 germ-line mutations in Scandinavian familial breast cancer
- 1997
-
Ingår i: American Journal of Human Genetics. - 0002-9297. ; 60:5, s. 1068-1078
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies of high-risk breast cancer families have proposed that two major breast cancer-susceptibility genes, BRCA1 and BRCA2, may account for at least two-thirds of all hereditary breast cancer. We have screened index cases from 106 Scandinavian (mainly southern Swedish) breast cancer and breast-ovarian cancer families for germ-line mutations in all coding exons of the BRCA1 and BRCA2 genes, using the protein-truncation test, SSCP analysis, or direct sequencing. A total of 24 families exhibited 11 different BRCA1 mutations, whereas 11 different BRCA2 mutations were detected in 12 families, of which 3 contained cases of male breast cancer. One BRCA2 mutation, 4486delG, was found in two families of the present study and, in a separate study, also in breast tumors from three unrelated males with unknown family history, suggesting that at least one BRCA2 founder mutation exists in the Scandinavian population. We report 1 novel BRCA1 mutation, eight additional cases of 4 BRCA1 mutations described elsewhere, and 11 novel BRCA2 mutations (9 frameshift deletions and 2 nonsense mutations), of which all are predicted to cause premature truncation of the translated products. The relatively low frequency of BRCA1 and BRCA2 mutations in the present study could be explained by insufficient screening sensitivity to the location of mutations in uncharacterized regulatory regions, the analysis of phenocopies, or, most likely, within predisposed families, additional uncharacterized BRCA genes.
|
|
| 3. |
- Haraldsson, K, et al.
(författare)
-
BRCA2 germ-line mutations are frequent in male breast cancer patients without a family history of the disease
- 1998
-
Ingår i: Cancer Research. - 1538-7445. ; 58:7, s. 71-1367
-
Tidskriftsartikel (refereegranskat)abstract
- Breast cancer is a rare disease in men, affecting less than 0.1% of the male population. Two heritable gene defects have been associated with a predisposition to male breast cancer development, ie., germ-line mutations in the breast cancer susceptibility gene BRCA2 and the androgen receptor (AR) gene. In this study, the entire coding regions of BRCA2 and AR were screened for mutations in 34 consecutive male breast cancer patients. Five different truncating BRCA2 mutations were identified in 7 (21%) of the 34 cases, with all mutations being of germ-line origin. Three of the mutated cases carried the same mutation (4186delG), which has been found earlier in two Swedish families with multiple female breast cancer cases. Haplotype analysis supported a common ancestry of 4186delG. One mutation, 6503delTT, was found in a male carrying also a previously identified COOH-terminal polymorphic stop codon (Lys3326ter). No differences were seen between mutation carriers and noncarriers with respect to clinical stage and estrogen or progesterone receptor status. Mutation carriers tended to be younger at diagnosis. No germ-line AR mutations were found in the present material, but the number of AR polyglutamine repeats tended to be lower among mutation carriers. Most surprisingly, only one of the seven BRCA2 mutation carriers had a positive family history of breast cancer, suggesting a lower penetrance of some BRCA2 mutations or an influence of modifying factors for disease development in males and females. The present study implies that approximately one-fifth of all male breast cancer cases in the Swedish population are due to germ-line BRCA2 mutations.
|
|
| 4. |
- Jóhannsson, O T, et al.
(författare)
-
Survival of BRCA1 breast and ovarian cancer patients : a population-based study from southern Sweden
- 1998
-
Ingår i: Journal of Clinical Oncology. - 0732-183X. ; 16:2, s. 397-404
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Recent studies indicate that BRCA1 breast and ovarian tumors may have an advantageous survival. In this population-based study, the survival of carriers of a mutated BRCA1 gene was investigated.PATIENTS AND METHODS: The survival of 71 BRCA1-associated cancer patients (33 breast cancer, seven breast and ovarian cancer, and 31 ovarian cancer patients from 21 families with BRCA1 germline mutations) diagnosed after 1958 was compared with that of a population-based comparison group that consisted of all other invasive breast (n = 28,281) and ovarian (n = 7,011) cancers diagnosed during 1958 to 1995, as well as an age- and stage-matched control group.RESULTS: No apparent survival advantage was found for BRCA1-associated breast cancers upon direct comparison. After adjustment for age and calendar year of diagnosis, survival was equal to or worse than that of the comparison group (hazards ratio [HR], 1.5; 95% confidence interval [CI], 0.9 to 2.4). In comparison with an age- and stage-matched control group, survival again appeared equal or worse (HR, 1.5; 95% CI, 0.6 to 3.7). For BRCA1-associated ovarian cancers, an initial survival advantage was noted that disappeared with time. Due to this time dependency, multivariate analyses cannot adequately be analyzed. Compared with the age- and stage-matched control group, survival again appeared equal or worse (HR, 1.2; 95% CI, 0.5 to 2.8).CONCLUSION: The results suggest that survival for carriers of a BRCA1 mutation may be similar, or worse than, that for breast and ovarian cancer in general. This finding is in accordance with the adverse histopathologic features observed in BRCA1 tumors and underlines the need for surveillance in families that carry a BRCA1 mutation.
|
|
| 5. |
- Jóhannsson, O T, et al.
(författare)
-
Tumour biological features of BRCA1-induced breast and ovarian cancer
- 1997
-
Ingår i: European Journal of Cancer. - 0959-8049. ; 33:3, s. 362-371
-
Tidskriftsartikel (refereegranskat)abstract
- BRCA1 mutations, although implicated in disease predisposition in a major part of the hereditary breast cancer population, do not seem to be crucially involved in tumorigenesis of sporadic breast and ovarian cancers. This suggests that tumours arising in BRCA1 mutation carriers may differ from BRCA1 negative hereditary and sporadic cancer in genetic and biological features, as well as in clinical behaviour. Prior to BRCA1 analysis, 79 breast and 19 ovarian tumours from 57 breast and breast-ovarian cancer families, and 170 tumours from a comparison group of stage II breast cancers were studied with regard to histopathological features; immunohistochemistry [c-erbB-2, p53, oestrogen receptor (ER) and progesterone receptor (PR)], DNA flow cytometry and S-phase fraction. BRCA1 mutations were found in 40 breast and 15 ovarian tumours. The BRCA1 positive breast tumours were significantly more often of ductal type, histological grade III and manifested a heavy lymphocyte infiltration. Additionally, as compared to BRCA1 negative tumours, the BRCA1 positive tumours were significantly more often ER, PgR and c-erbB-2 negative. Furthermore, they were significantly more often DNA non-diploid, as well as being characterised by higher S-phase fraction values. These results suggest that BRCA1-induced breast cancers may manifest distinct tumour biological features of clinical importance.
|
|
| 6. |
- Tirkkonen, M, et al.
(författare)
-
Distinct somatic genetic changes associated with tumor progression in carriers of BRCA1 and BRCA2 germ-line mutations
- 1997
-
Ingår i: Cancer Research. - 0008-5472. ; 57:7, s. 7-1222
-
Tidskriftsartikel (refereegranskat)abstract
- BRCA1 and BRCA2 mutations confer increased risk for development of breast cancer, but a number of additional, currently largely unknown, somatic genetic defects must also accumulate in the breast epithelial cells before malignancy develops. To evaluate the nature of these additional somatic genetic defects, we performed a genome-wide survey by comparative genomic hybridization on breast cancers from 21 BRCA1 mutation carriers, 15 BRCA2 mutation carriers, and 55 unselected controls. The total number of genetic changes was almost two times higher in tumors from both BRCA1 and BRCA2 mutation carriers than in the control group. In BRCA1 tumors, losses of 5q (86%), 4q (81%), 4p (64%), 2q (40%), and 12q (40%) were significantly more common than in the control group (7-13%). BRCA2 tumors were characterized by a higher frequency of 13q (73%) and 6q (60%) losses and gains of 17q22-q24 (87%) and 20q13 (60%) as compared to the prevalence of these changes in the control group (12-18%). In conclusion, accumulation of somatic genetic changes during tumor progression may follow a unique pathway in individuals genetically predisposed to cancer, especially by the BRCA1 gene. Activation or loss of genes in the affected chromosomal regions may be selected for during tumor progression in cells lacking functional BRCA1 or BRCA2. Identification of such genes could provide targets for therapeutic intervention and early diagnosis.
|
|
| 7. |
- Tirkkonen, M, et al.
(författare)
-
Somatic genetic alterations in BRCA2-associated and sporadic male breast cancer
- 1999
-
Ingår i: Genes, Chromosomes and Cancer. - 1045-2257. ; 24:1, s. 56-61
-
Tidskriftsartikel (refereegranskat)abstract
- The genetic changes underlying the development and progression of male breast cancer are poorly understood. Germline BRCA2 mutations account for a significant part of male breast cancer, but the majority of patients lack a known inherited predisposition. We recently demonstrated that the progression of breast cancer in female carriers of a germline BRCA1 or BRCA2 mutation follows specific genetic pathways, distinct from each other and from sporadic breast cancer. In the present study, we performed a genome-wide survey by comparative genomic hybridization (CGH) of somatic genetic aberrations in 26 male breast cancers, including five tumors from BRCA2 mutation carriers. BRCA2 tumors exhibited a significantly higher number of chromosomal aberrations than sporadic tumors. The most common alterations in sporadic male breast cancer were +1q (38%), +8q (33%), +17q (33%), -13q (29%), and -8p (24%). In tumors from BRCA2 mutation carriers, the five most common genetic changes were +8q (100%), +20q (100%), +17q (80%), -13q (80%), and -6q (60%). The CGH results in these two groups of male breast cancers are almost identical to those identified in the corresponding sporadic and BRCA2-associated female breast cancers. The results suggest that despite substantial hormonal differences between females and males, similar genetic changes are selected for during tumor progression. Furthermore, the presence of a highly penetrant germline BRCA2 mutation apparently leads to a characteristic somatic tumor progression pathway, again shared between affected male and female mutation carriers.
|
|
| 8. |
- van den Berg, J, et al.
(författare)
-
Allelic loss at chromosome 13q12-q13 is associated with poor prognosis in familial and sporadic breast cancer
- 1996
-
Ingår i: British Journal of Cancer. - 0007-0920. ; 74:10, s. 1615-1619
-
Tidskriftsartikel (refereegranskat)abstract
- Loss of heterozygosity (LOH) was analysed in 84 primary tumours from sporadic, familial and hereditary breast cancer using five microsatellite markers spanning the chromosomal region 13q12-q13 which harbours the BRCA2 breast cancer susceptibility gene, and using one other marker located within the RBI tumour-suppressor gene at 13q14. LOH at the BRCA2 region was found in 34% and at RBI in 27% of the tumours. Selective LOH at BRCA2 occurred in 7% of the tumours, whereas selective LOH at RBI was observed in another 7%. Moreover, a few tumours demonstrated a restricted deletion pattern, suggesting the presence of additional tumour-suppressor genes both proximal and distal of BRCA2. LOH at BRCA2 was significantly correlated to high S-phase values, low oestrogen and progesterone receptor content and DNA non-diploidy. LOH at BRCA2 was also associated, albeit non-significantly, with large tumour size and the ductal and medullar histological types. No correlation was found with lymph node status, patient age or a family history of breast cancer. A highly significant and independent correlation existed between LOH at BRCA2 and early recurrence and death. LOH at RBI was not associated with the above mentioned factors or prognosis. The present study does not provide conclusive evidence that BRCA2 is the sole target for deletions at 13q12-q13 in breast tumours. However, the results suggest that inactivation of one or several tumour-suppressor genes in the 13q12-q13 region confer a strong tumour growth potential and poor prognosis in both familial and sporadic breast cancer.
|
|
