| 1. |
- Borg, Åke, et al.
(författare)
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High frequency of multiple melanomas and breast and pancreas carcinomas in CDKN2A mutation-positive melanoma families
- 2000
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Ingår i: Journal of the National Cancer Institute. - 0027-8874. ; 92:15, s. 6-1260
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: : Inherited mutations in the CDKN2A tumor suppressor gene, which encodes the p16(INK4a) protein, and in the cyclin-dependent kinase 4 (CDK4) gene confer susceptibility to cutaneous malignant melanoma. We analyzed families with two or more cases of melanoma for germline mutations in CDKN2A and CDK4 to elucidate the contribution of these gene defects to familial malignant melanoma and to the occurrence of other cancer types.METHODS: : The entire CDKN2A coding region and exon 2 of the CDK4 gene of an affected member of each of 52 families from southern Sweden with at least two cases of melanoma in first- or second-degree relatives were screened for mutations by use of polymerase chain reaction-single-strand conformation polymorphism analysis. Statistical tests were two-sided.RESULTS: : CDKN2A mutations were found in 10 (19%) of the 52 families. Nine families carried an identical alteration consisting of the insertion of arginine at position 113 of p16(INK4a), and one carried a missense mutation, in which the valine at position 115 was replaced with a glycine. The 113insArg mutant p16(INK4a) was unable to bind cdk4 and cdk6 in an in vitro binding assay. Six of the 113insArg families had at least one member with multiple primary melanomas; the 113insArg families also had a high frequency of other malignancies-in particular, breast cancer (a total of eight cases compared with the expected 2.1; P =.0014) and pancreatic cancer (a total of six cases compared with the expected 0.16; P<.0001). Families with breast cancer also had a propensity for multiple melanomas in females, suggesting that a sex-dependent factor may modify the phenotypic expression of CDKN2A alterations.CONCLUSIONS: : Our findings confirm that the majority of CDKN2A-associated melanoma families in Sweden are due to a single founder mutation. They also show that families with the CDKN2A 113insArg mutation have an increased risk not only of multiple melanomas and pancreatic carcinoma but also of breast cancer.
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| 2. |
- Kainu, T, et al.
(författare)
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Somatic deletions in hereditary breast cancers implicate 13q21 as a putative novel breast cancer susceptibility locus
- 2000
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 97:17, s. 9603-9608
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Tidskriftsartikel (refereegranskat)abstract
- A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
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| 3. |
- Kauraniemi, P, et al.
(författare)
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MYB oncogene amplification in hereditary BRCA1 breast cancer
- 2000
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Ingår i: Cancer Research. - 1538-7445. ; 60:19, s. 5323-5328
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Tidskriftsartikel (refereegranskat)abstract
- Comparative genomic hybridization analysis has demonstrated that breast tumors from BRCA1 and BRCA2 germ-line mutation carriers contain a large number of chromosomal copy number gains and losses. A high regional copy number gain at 6q22-q24 was observed in one BRCA1 tumor, and fluorescence in situ hybridization analysis indicated a strong amplification of the MYB oncogene (15 copies of MYB compared with 1 copy of chromosome 6 centromere). Fluorescence in situ hybridization analysis revealed amplification of MYB in 5 (29%) of 17 BRCA1 breast tumors, whereas none of 8 BRCA2 tumors and 13 breast cancer cell lines, and only 2 of 100 sporadic breast tumors exhibited altered MYB copy numbers. Gene amplification resulted in mRNA overexpression as determined by Northern blot and cDNA microarray analysis, and protein overexpression by immunohistochemical staining. We conclude that MYB amplification is infrequent in sporadic breast cancer but common in breast tumors from BRCA1 mutation carriers, suggesting a role of this cell cycle regulator and transcription factor in the progression of some BRCA1 tumors. However, we cannot rule out the significance of other genes in the 6q22-q24 amplicon.
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| 4. |
- Loman, Niklas, et al.
(författare)
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Prognosis and clinical presentation of BRCA2-associated breast cancer
- 2000
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Ingår i: European Journal of Cancer. - 1879-0852. ; 36:11, s. 1365-1373
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Tidskriftsartikel (refereegranskat)abstract
- 54 female breast cancer patients from 22 families with BRCA2 germ line mutations from Sweden and Denmark were compared with 214 age- and date of diagnosis-matched controls identified among breast cancer patients from South Sweden. At diagnosis, BRCA2-associated cases were more often node-positive (N+). OR=1.9 (95% confidence interval (CI)=1.0-3.6; P=0.036), and were more often clinical stage IV: OR=4.6 (95% CI=1.3-17; P=0.021) than the controls. Bilateral disease was also more common among the BRCA2-associated cases: OR=2. 4 (95% CI=1.1-5.3; P=0.027). Breast cancer-specific survival (BCSS) was significantly worse among the BRCA2-associated cases: RR=2.0 (95% CI=1.2-3.4; P=0.010). When stage was corrected for in a multivariate analysis, BCSS was no longer significantly worse for the BRCA2-associated cases: RR=1.6 (95% CI=0.85-3.1). The corresponding effect after correction for bilateral disease was: RR=1.8 (95% CI=1.0-3.1; P=0.034). The unfavourable prognosis in BRCA2-associated breast cancer seems, to a great extent, to be a consequence of the higher clinical stage at diagnosis. The increased presence of bilateral cancers appears to have less impact on survival in this group of hereditary breast cancer. Data presented here needs to be taken into account when counselling healthy carriers of BRCA2 germ line mutations.
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| 5. |
- Planck, M, et al.
(författare)
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Somatic frameshift alterations in mononucleotide repeat-containing genes in different tumor types from an HNPCC family with germline MSH2 mutation
- 2000
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Ingår i: Genes, Chromosomes and Cancer. - 1045-2257. ; 29:1, s. 33-39
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Tidskriftsartikel (refereegranskat)abstract
- Hereditary nonpolyposis colorectal cancer (HNPCC) is caused by a germline mutation in one of several DNA repair genes, which in the tumors is reflected as microsatellite instability (MSI). MSI+ tumors have been found to carry somatic frameshift mutations in mononucleotide repeats within the coding regions of several genes involved in growth control, apoptosis, and DNA repair, e.g., TGFBRII, BAX, IGFIIR, TCF4, MSH3, and MSH6. We have studied the occurrence of somatic frameshift alterations in these mononucleotide repeat-containing genes in 24 tumors (15 colorectal cancers, 1 colon adenoma, 4 endometrial cancers, 1 ovarian cancer, 1 gastric cancer, 1 urothelial cancer, and 1 duodenal cancer) from 14 individuals in an HNPCC family with germline hMSH2 mutation. Such somatic frameshift mutations occurred at a variable frequency; the long mononucleotide repeats that characterize intronic MSI markers were mutated in the majority of tumors, 13 of the tumors displayed alterations in the (A)(10) tract of TGFBII, eight tumors (all of gastrointestinal origin) had alterations in the (A)(9) repeat of TCF4, and one to five tumors had somatic frameshift alterations in the shorter mononucleotide repeats of IGFIIR, BAX, MSH3, and MSH6. Thus, longer mononucleotide repeats were more frequently affected by somatic frameshift mutations. The pattern of alterations varied between the tumors from different family members as well as between different tumors from the same individual. To what extent this variable pattern depends on the widespread mismatch repair deficiency induced by the underlying MSH2 mutation, or represents alternative ways whereby the tumors can achieve a tumorigenic phenotype, is unknown. We suggest, however, that the accumulation of somatic frameshifts, rather than the specific loci in which these occur, drives the development of the tumorigenic phenotype in HNPCC.
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