CDKN2A mutations and MC1R variants in Italian patients with single or multiple primary melanoma

We evaluated the contribution of germline CDKN2A mutations and MC1R variants to the development of melanoma in a hospital-based study of single (SPM, n = 398) and multiple primary melanoma (MPM, n = 95). The overall frequency of CDKN2A mutations was 15.2%, and four-fold higher in MPM than in SPM cases (OR = 4.27; 95% CI 2.43-7.53). The likelihood of identifying a CDKN2A mutation increased with family history of melanoma and younger age at diagnosis in MPM cases. Compared to SPM patients, the risk of harboring a CDKN2A mutation rose as the number of primary melanomas increased and was not influenced by family history. The G101W and E27X founder mutations were the most common. Several other mutations (W15X, Q50X, R58X, A68L, A127P and H142R) were detected for the first time in Italian patients. One novel mutation, T77A, was identified. Several non-coding variants with unknown functional significance were also found (5'UTR -25C > T, -21C > T, -67G > C, IVS1 +37G > C); the novel 5'UTR -21C > T variant was not detected in controls. The CDKN2A A148T polymorphism was more frequent in MPM patients than in the control population (15.7% versus 6.6%). Compared to the SPM patients, MPM cases had a 2-fold increased probability of being MC1R variant carriers and a higher probability of carrying two or more variants. No specific association was observed between the type of variant and the number of melanomas, suggesting that the number rather than the type of MC1R variant increases the risk of MPM. We observed no interaction between CDKN2A status and the presence of MC1R variants. The high frequency of CDKN2A mutations in our MPM cases, independent of their family history, is of relevance to genetic counseling and testing in our population.     

BRCA1 and BRCA2 germline mutations in Malaysian women with early-onset breast cancer without a family history

Background

In Asia, breast cancer is characterised by an early age of onset: In Malaysia, approximately 50% of cases occur in women under the age of 50 years. A proportion of these cases may be attributable, at least in part, to genetic components, but to date, the contribution of genetic components to breast cancer in many of Malaysia''s ethnic groups has not been well-characterised.

Methodology

Given that hereditary breast carcinoma is primarily due to germline mutations in one of two breast cancer susceptibility genes, BRCA1 and BRCA2, we have characterised the spectrum of BRCA mutations in a cohort of 37 individuals with early-onset disease (≤40 years) and no reported family history. Mutational analysis of BRCA1 and BRCA2 was conducted by full sequencing of all exons and intron-exon junctions.

Conclusions

Here, we report a total of 14 BRCA1 and 17 BRCA2 sequence alterations, of which eight are novel (3 BRCA1 and 5 BRCA2). One deleterious BRCA1 mutation and 2 deleterious BRCA2 mutations, all of which are novel mutations, were identified in 3 of 37 individuals. This represents a prevalence of 2.7% and 5.4% respectively, which is consistent with other studies in other Asian ethnic groups (4–9%).     

Rare mutations in XRCC2 increase the risk of breast cancer

An exome-sequencing study of families with multiple breast-cancer-affected individuals identified two families with XRCC2 mutations, one with a protein-truncating mutation and one with a probably deleterious missense mutation. We performed a population-based case-control mutation-screening study that identified six probably pathogenic coding variants in 1,308 cases with early-onset breast cancer and no variants in 1,120 controls (the severity grading was p < 0.02). We also performed additional mutation screening in 689 multiple-case families. We identified ten breast-cancer-affected families with protein-truncating or probably deleterious rare missense variants in XRCC2. Our identification of XRCC2 as a breast cancer susceptibility gene thus increases the proportion of breast cancers that are associated with homologous recombination-DNA-repair dysfunction and Fanconi anemia and could therefore benefit from specific targeted treatments such as PARP (poly ADP ribose polymerase) inhibitors. This study demonstrates the power of massively parallel sequencing for discovering susceptibility genes for common, complex diseases.     

MC1R genotype modifies risk of melanoma in families segregating CDKN2A mutations

Mutations in the exons of the cyclin-dependent kinase inhibitor gene CDKN2A are melanoma-predisposition alleles which have high penetrance, although they have low population frequencies. In contrast, variants of the melanocortin-1 receptor gene, MC1R, confer much lower melanoma risk but are common in European populations. Fifteen Australian CDKN2A mutation-carrying melanoma pedigrees were assessed for MC1R genotype, to test for possible modifier effects on melanoma risk. A CDKN2A mutation in the presence of a homozygous consensus MC1R genotype had a raw penetrance of 50%, with a mean age at onset of 58.1 years. When an MC1R variant allele was also present, the raw penetrance of the CDKN2A mutation increased to 84%, with a mean age at onset of 37.8 years (P=.01). The presence of a CDKN2A mutation gave a hazard ratio of 13.35, and the hazard ratio of 3.72 for MC1R variant alleles was also significant. The impact of MC1R variants on risk of melanoma was mediated largely through the action of three common alleles, Arg151Cys, Arg160Trp, and Asp294His, that have previously been associated with red hair, fair skin, and skin sensitivity to ultraviolet light.     

Clinical features predicting identification of CDKN2A mutations in Italian patients with familial cutaneous melanoma

CDKN2A is the most common, most penetrant gene whom germline mutations predisposing to cutaneous familial melanoma (FAM). Multiple primary melanoma (MPM), early age at onset, >2 affected members and pancreatic cancer are consistent features predicting positive test. However, the impact that cumulative clinical features have on the likelihood of molecular testing is unknown. In this work, genotype-phenotype correlations focused on selected clinical features were performed in 100 Italian FAM unrelated patients. Molecular studies of CDKN2A mutations were performed by direct sequencing. Statistical study included multiple correspondence analysis, uni- and multivariate analyses, and individual patient's probability calculation. MPM, >2 affected family members, Breslow thickness >0.4mm, and age at onset ≤41 years were the unique independent features predicting positive CDKN2A screening. The rate of positive testing ranged from 93.2% in the presence of all of them, to 0.4% in their absence. The contribution of each of them was quantified accordingly, with MPM being the most significant. These findings confirm previous data and add novel insights for the role of accurate patients' selection in CDKN2A screening.     

Frequent variations in cancer-related genes may play prognostic role in treatment of patients with chronic myeloid leukemia

Genome variability of host genome and cancer cells play critical role in diversity of response to existing therapies and overall success in treating oncological diseases. In chronic myeloid leukemia targeted therapy with tyrosine kinase inhibitors demonstrates high efficacy in most of the patients. However about 15 % of patients demonstrate primary resistance to standard therapy. Whole exome sequencing is a good tool for unbiased search of genetic variations important for prognosis of survival and therapy efficacy in many cancers. We apply this approach to CML patients with optimal response and failure of tyrosine kinase therapy. We analyzed exome variations between optimal responders and failures and found 7 variants in cancer-related genes with different genotypes in two groups of patients. Five of them were found in optimal responders: rs11579366, rs1990236, rs176037, rs10653661, rs3803264 and two in failures: rs3099950, rs9471966. These variants were found in genes associated with cancers (ANKRD35, DNAH9, MAGEC1, TOX3) or participating in cancer-related signaling pathways (THSD1, MORN2, PTCRA). We found gene variants which may become early predictors of the therapy outcome and allow development of new early prognostic tests for estimation of therapy efficacy in CML patients. Normal genetic variation may influence therapy efficacy during targeted treatment of cancers.     

Molecular characterization of germline mutations in the BRCA1 and BRCA2 genes from breast cancer families in Taiwan

A total of 18 families with multiple cases of breast cancer were identified from southern Taiwan, and 5 of these families were found to carry cancer-associated germline mutations in the BRCA1 and BRCA2 genes. One novel cryptic splicing mutation of the BRCA1 gene, found in two unrelated families, was shown to be a deletion of 10 bp near the branch site in intron 7. This mutation causes an insertion of 59 nucleotides derived from intron 7 and results in a frameshift, leading to premature translational termination of BRCA1 mRNA in exon 8. Deletions of 2670delC, 3073delT and 6696-7delTC in the BRCA2 gene were found in three other breast cancer families. All three deletions are predicted to generate frameshifts and to result in the premature termination of BRCA2 protein translation. Several genetic polymorphisms in both BRCA1 and BRCA2 genes were also detected in this investigation. Received: 28 September 1998 / Accepted: 20 November 1998     

Identification of somatic and germline mitochondrial DNA sequence variants in prostate cancer patients

Prostate cancer (PCa) is the second most frequent cancer among men in the European Union and the most common in the United States. Older age and a positive family history of PCa are important risk factors, but little is known about the disease aetiology. Mitochondria are involved in essential cellular pathways, some of which have been associated with tumorigenesis. We analysed the presence of sequence variants, depletion and rearrangements in the mitochondrial DNA (mtDNA) of PCa patients. Sequencing of the D-loop and genes RNR1 and 2, ND3, ND4L and ND4, and long-range and real-time PCR techniques were carried out on 51 samples (41 from patients and 10 from controls). Normal, hyperplastic or tumour samples were obtained from 17 patients. Six patients' seminal vesicles were also investigated as an additional patient's control tissue (these structures seldom develop tumours). Neither depletion nor mtDNA rearrangements were detected. In contrast, 94 mtDNA sequence variants were identified, 9 previously unreported. The regions presenting more sequence variants were MT-DLOOP (52%), MT-RNR2 (14%) and MT-ND4 (13%). The patients' seminal vesicles studied showed the same set of variants as the corresponding prostate, suggesting either that the pathogenic role of these particular variants is minor or that they participate in the prostatic carcinogenesis in combination with other factors absent in seminal vesicles. Five patients (29.4%) harboured eight somatic changes in the mtDNA. One affects a conserved residue and three have not been previously described. The analysis of other genes in the mtDNA molecule might demonstrate an even higher incidence of mtDNA somatic variants in these PCa patients.     

Imprinting status of 11p15 genes in Beckwith-Wiedemann syndrome patients with CDKN1C mutations.

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder characterized by somatic overgrowth, congenital malformations, and predisposition to childhood tumors. Aberrant expression of multiple imprinted genes, including H19, IGF2, KCNQ1OT1, and CDKN1C, has been observed in BWS patients. It has been estimated that mutations in CDKN1C occur in 12-17% of BWS patients. We have screened 10 autosomal dominant pedigrees and 65 sporadic BWS cases by PCR/heteroduplex analysis and DNA sequencing and have identified four mutations, two of which were associated with biallelic IGF2 expression and normal H19 and KCNQ1OT1 imprinting. One patient demonstrated phenotypic expression of paternally transmitted mutation in this maternally expressed gene, a second proband is the child of one of a pair of monozygotic twin females who carry the mutation de novo, and a third patient exhibited unusual skeletal changes more commonly found in other overgrowth syndromes. When considered with other studies published to date, this work reveals the frequency of CDKN1C mutations in BWS to be only 4.9%. This is the first report of an analysis of the imprinting status of genes in the 11p15 region where CDKN1C mutations were associated with loss of IGF2 imprinting and maintenance of H19 and KCNQ1OT1 imprinting.     

In vitro behavior and UV response of melanocytes derived from carriers of CDKN2A mutations and MC1R variants

Coinheritance of germline mutation in cyclin‐dependent kinase inhibitor 2A (CDKN2A) and loss‐of‐function (LOF) melanocortin 1 receptor (MC1R) variants is clinically associated with exaggerated risk for melanoma. To understand the combined impact of these mutations, we established and tested primary human melanocyte cultures from different CDKN2A mutation carriers, expressing either wild‐type MC1R or MC1RLOF variant(s). These cultures expressed the CDKN2A product p16 (INK4A) and functional MC1R. Except for 32ins24 mutant melanocytes, the remaining cultures showed no detectable aberrations in proliferation or capacity for replicative senescence. Additionally, the latter cultures responded normally to ultraviolet radiation (UV) by cell cycle arrest, JNK, p38, and p53 activation, hydrogen peroxide generation, and repair of DNA photoproducts. We propose that malignant transformation of melanocytes expressing CDKN2A mutation and MC1RLOF allele(s) requires acquisition of somatic mutations facilitated by MC1R genotype or aberrant microenvironment due to CDKN2A mutation in keratinocytes and fibroblasts.     

Novel germline hMSH2 genomic deletion and somatic hMSH2 mutations in a hereditary nonpolyposis colorectal cancer family

Germline and somatic mutations of the hMSH2 gene were determined in a Japanese hereditary nonpolyposis colorectal cancer (HNPCC) family fulfilling the Amsterdam criteria. PCR-SSCP-sequencing of genomic DNA detected a somatic hMSH2 mutation of an A deletion at codon 227-229 in a duodenal carcinoma and a somatic hMSH2 mutation of an A insertion at codon 21 in a gastric carcinoma from affected family members, both carcinomas exhibiting high microsatellite instability. However, no germline hMSH2 mutation was detected by the PCR-SSCP-sequencing method. Genomic DNA was then analyzed by Southern blot hybridization using three hMSH2 cDNA probes (probe A involving exons 1-5, probe B involving exons 4-11 and probe C involving exons 9-16) after digestion by restriction enzymes, EcoRI, HindIII and NsiI. The NsiI digest of DNA from normal tissues of affected members exhibited an aberrant 8.6 kb restriction fragment, in addition to the normal 10.6 kb fragment, when hybridized to probes A and B. This suggested the presence of a heterozygous 2kb genomic deletion encompassing exon 4, 5 or 6. RT-PCR-sequencing revealed that the deleted region encompassed exon 5. This novel genomic deletion of the hMSH2 gene was confirmed to be pathogenic, and the Southern hybridization pattern was applied to the pre-symptomatic diagnosis.     

Prostate cancer with variants in CYP17 and UGT2B17 genes: a meta-analysis

Both CYP17 and UGT2B17 are suggested to be potential risk factors of prostate cancer (PCa). To date, many studies have evaluated the relationship between CYP17 T-34C and UGT2B17 Del polymorphisms and Prostate cancer with conflicting results. Here, we performed comprehensive meta-analyses of over 25 studies, including results from about 17,000 subjects on the association of CYP17 T-34C and UGT2B17 Del polymorphisms with Prostate cancer. Overall, no significant associations between CYP17 T-34C polymorphism and Prostate cancer risk were found for T versus C (P=0.63), TT versus CC (P=0.52), TT+TC versus CC (P=0.40) or TT versus TC+CC (P=0.98), though there was a marginally significant association with the UGT2B17 Del polymorphism under Del/Del versus Ins/Ins +Ins/Del (P=0.05). In an analysis of various subgroups, there were no substantially significant associations with the CYP17 T-34C polymorphism; while there was a significant association for the UGT2B17 Del/Del genotype in a subgroup of men-based controls (P < 0.0001). The current meta-analysis results suggest that the CYP17 T-34C polymorphism may not be associated with Prostate cancer, while the UGT2B17 Del polymorphism may significantly contribute to prostate cancer susceptibility in men. These findings also support the idea that CYP17 has no significant effects on androgen levels, while UGT2B17 does.     

Laparoscopic hysterectomy with or without pelvic lymphadenectomy or sampling in a high-risk series of patients with endometrial cancer

Background

The purpose of the study was to determine the outcome of all patients with endometrial adenocarcinoma cancer treated by laparoscopic hysterectomy at our institution, many of whom were high-risk for surgery.

Methods

Data was collected by a retrospective search of the case notes and Electronic Patient Records of the thirty eight patients who underwent laparoscopic hysterectomy for endometrial cancer at our institutions.

Results

The median body mass index was 30 (range 19–67). Comorbidities were present in 76% (29 patients); 40% (15 patients) had a single comorbid condition, whilst 18% (7 patients) had two, and a further 18% (7 patients) had more than two. Lymphadenectomy was performed in 45% (17 patients), and lymph node sampling in 21% (8 patients). Median operating time was 210 minutes (range 70–360 minutes). Median estimated blood loss was 200 ml (range 50–1000 ml). There were no intraoperative complications. Post-operative complications were seen in 21% (2 major, 6 minor). Blood transfusion was required in 5% (2 patients). The median stay was 4 post-operative nights (range 1–25 nights). In those patients undergoing lymphadenectomy, the mean number of nodes taken was fifteen (range 8–26 nodes). The pathological staging was FIGO stage I 76% (29 patients), stage II 8% (3 patients), stage III 16% (6 patients). The pathological grade was G1 31% (16 patients), G2 45% (17 patients), G3 24% (8 patients).

Conclusion

Laparoscopic hysterectomy can be safely carried out in patients at high risk for surgery, with no compromise in terms of outcomes, whilst providing all the benefits inherent in minimal access surgery.

     

Prevalence and penetrance of germline BRCA1 and BRCA2 mutations in a population series of 649 women with ovarian cancer

A population-based series of 649 unselected incident cases of ovarian cancer diagnosed in Ontario, Canada, during 1995-96 was screened for germline mutations in BRCA1 and BRCA2. We specifically tested for 11 of the most commonly reported mutations in the two genes. Then, cases were assessed with the protein-truncation test (PTT) for exon 11 of BRCA1, with denaturing gradient gel electrophoresis for the remainder of BRCA1, and with PTT for exons 10 and 11 of BRCA2. No mutations were found in all 134 women with tumors of borderline histology. Among the 515 women with invasive cancers, we identified 60 mutations, 39 in BRCA1 and 21 in BRCA2. The total mutation frequency among women with invasive cancers, 11.7% (95% confidence interval [95%CI] 9.2%-14.8%), is higher than previous estimates. Hereditary ovarian cancers diagnosed at age <50 years were mostly (83%) due to BRCA1, whereas the majority (60%) of those diagnosed at age >60 years were due to BRCA2. Mutations were found in 19% of women reporting first-degree relatives with breast or ovarian cancer and in 6.5% of women with no affected first-degree relatives. Risks of ovarian, breast, and stomach cancers and leukemias/lymphomas were increased nine-, five-, six- and threefold, respectively, among first-degree relatives of cases carrying BRCA1 mutations, compared with relatives of noncarriers, and risk of colorectal cancer was increased threefold for relatives of cases carrying BRCA2 mutations. For carriers of BRCA1 mutations, the estimated penetrance by age 80 years was 36% for ovarian cancer and 68% for breast cancer. In breast-cancer risk for first-degree relatives, there was a strong trend according to mutation location along the coding sequence of BRCA1, with little evidence of increased risk for mutations in the 5' fifth, but 8.8-fold increased risk for mutations in the 3' fifth (95%CI 3.6-22.0), corresponding to a carrier penetrance of essentially 100%. Ovarian, colorectal, stomach, pancreatic, and prostate cancer occurred among first-degree relatives of carriers of BRCA2 mutations only when mutations were in the ovarian cancer-cluster region (OCCR) of exon 11, whereas an excess of breast cancer was seen when mutations were outside the OCCR. For cancers of all sites combined, the estimated penetrance of BRCA2 mutations was greater for males than for females, 53% versus 38%. Past studies may have underestimated the contribution of BRCA2 to ovarian cancer, because mutations in this gene cause predominantly late-onset cancer, and previous work has focused more on early-onset disease. If confirmed in future studies, the trend in breast-cancer penetrance, according to mutation location along the BRCA1 coding sequence, may have significant impact on treatment decisions for carriers of BRCA1-mutations. As well, BRCA2 mutations may prove to be a greater cause of cancer in male carriers than previously has been thought.     

Two percent of men with early-onset prostate cancer harbor germline mutations in the BRCA2 gene

Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were 相似文献   

Genotyping of BRCA1, BRCA2, and CHEK2 germline mutations in Russian breast cancer patients using diagnostic biochips

The identification of BRCA1/2 and CHEK2 germline mutations is central to the molecular diagnostics of susceptibility to breast or/and ovarian cancer. A microarray-based rapid genotyping technique has been developed for identifying BRCA1 (185delAG, 300T>G, 4153delA, 5382insC, and 4158 A>G, 5382insC), BRCA2 (695insT and 6174delT), and CHEK2 (1100delC) mutations. It was applied for 412 randomly collected breast-cancer specimens from central Russia. In 25 (6.0%) patients, breast cancer was associated with other tumors of, e.g., ovarian, cervical, or colorectal cancer. BRCA1/2 and CHEK2 mutations were detected in 33 breast-cancer patients (8.0%). The most frequent mutations were BRCA1 5382insC, which was found in 16 patients (3.9%), and CHEK2 1100delC, which was detected in seven patients (1.7%). The suggested diagnostic microarray proved to be an efficient means of identifying BRCA1/2 and CHEK2 founder mutations most frequent in central Russia and can be proposed as a high-throughput diagnostic tool for clinical genetic testing.     

One third of Japanese patients with multiple osteochondromas may have mutations in genes other than EXT1 or EXT2

Multiple osteochondromas (MO; also referred to as hereditary multiple exostoses [HME] in the literature) is an autosomal dominant disorder characterized by benign, cartilage-capped bone tumors that grow from the metaphyses of long bones. Two genes are associated with this disease: EXT1 on 8q24.11-q24.13 and EXT2 on 11p12-p11. Mutations in EXT1 and EXT2 are found in 54-96% of patients with MO and are generally more frequent in EXT1 than in EXT2. We previously studied 43 Japanese families with MO using single-strand conformation polymorphism analysis for EXT1 and EXT2, and reported 23 families (54%) with mutations and 20 families (46%) with no mutations in these genes. Among the families with mutations, 17 families (40%) had mutations in EXT1, and 6 families (14%) had mutations in EXT2. Here we examined the same 43 Japanese families using denaturing high-performance liquid chromatography as an alternative technique. We detected five mutations, three of which are novel, in seven families in addition to the previously described mutations. In summary, we detected mutations in EXT1 or EXT2 in 30 (70%) out of 43 families. Our result suggests the presence of other gene(s) responsible for MO, at least in Japanese patients.     

Frequency of mutations in BRCA genes and other candidate genes in high-risk probands or probands with breast or ovarian cancer in the Czech Republic

Molecular Biology Reports - Breast cancer is currently the most common form of malignant tumour in womenboth in the Czech Republic and in most countries of the western world, and its incidence is...     

Genetic variants in telomere‐maintenance genes are associated with ovarian cancer risk and outcome

Most ovarian cancer patients present at an advanced stage with poor prognosis. Telomeres play a critical role in protecting chromosomes stability. The associations of genetic variants in telomere maintenance genes and ovarian cancer risk and outcome are unclear. We genotyped 137 single nucleotide polymorphisms (SNPs) in telomere‐maintenance genes in 417 ovarian cancer cases and 417 matched healthy controls to evaluate their associations with cancer risk, survival and therapeutic response. False discovery rate Q‐value was calculated to account for multiple testing. Eleven SNPs from two genes showed nominally significant associations with the risks of ovarian cancer. The most significant SNP was TEP1: rs2228026 with participants carrying at least one variant allele exhibiting a 3.28‐fold (95% CI: 1.72‐6.29; P < 0.001, Q = 0.028) increased ovarian cancer risk, which remained significant after multiple testing adjusting. There was also suggested evidence for the associations of SNPs with outcome, although none of the associations had a Q < 0.05. Seven SNPs from two genes showed associations with ovarian cancer survival (P < 0.05). The strongest association was found in TNKS gene (rs10093972, hazard ratio = 1.88; 95% CI: 1.20‐2.92; P = 0.006, Q = 0.076). Five SNPs from four genes showed suggestive associations with therapeutic response (P < 0.05). In a survival tree analysis, TEP1:rs10143407 was the primary factor contributing to overall survival. Unfavourable genotype analysis showed a cumulative effect of significant SNPs on ovarian cancer risk, survival and therapeutic response. Genetic variations in telomere‐maintenance genes may be associated with ovarian cancer risk and outcome.