Department of Genetics and Pathomorphology, International Hereditary Cancer Center, Pomeranian Medical University in Szczecin, Szczecin, Poland.
School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and the Hunter Medical Research Institute, Newcastle, New South Wales, Australia.
PLoS One. 2018 Oct 4;13(10):e0204768. doi: 10.1371/journal.pone.0204768. eCollection 2018.
The association of BRCA1/2 mutations with melanoma is not completely determined; the interpretation of variants of unknown significance is also problematic. To evaluate these issues we explored the molecular basis of melanoma risk by performing whole-exome sequencing on a cohort of 96 unrelated Polish early-onset melanoma patients and targeted sequencing of BRCA1/2 genes on additional 30 melanoma patients with familial aggregation of breast and other cancers. Sequencing was performed on peripheral blood. We evaluated MutationTaster, Polyphen2, SIFT, PROVEAN algorithms, analyzed segregation with cancer disease (in both families with identified BRCA2 variants) and in one family performed LOH (based on 2 primary tumors). We found neither pathogenic mutations nor variants of unknown significance within BRCA1. We identified two BRCA2 variants of unknown significance: c.9334G>A and c.4534 C>T. Disease allele frequency was evaluated by genotyping of 1230 consecutive melanoma cases, 5000 breast cancer patients, 3500 prostate cancers and 9900 controls. Both variants were found to be absent among unselected cancer patients and healthy controls. The MutationTaster, Polyphen2 and SIFT algorithms indicate that c.9334G>A is a damaging variant. Due to lack of tumour tissue LOH analysis could not be performed for this variant. The variant segregated with the disease. The c.4534 C>T variant did not segregate with disease, there was no LOH of the variant. The c.9334G>A variant, classified as a rare variant of unknown significance, on current evidence may predisposes to cancers of the breast, prostate and melanoma. Functional studies to describe how the DNA change affects the protein function and a large multi-center study to evaluate its penetrance are required.
BRCA1/2 突变与黑色素瘤的相关性尚未完全确定，对意义不明的变异的解读也是一个问题。为了评估这些问题，我们对 96 名波兰早期发病的无关联黑色素瘤患者进行了外显子组测序，并对 30 名有家族性乳腺癌和其他癌症聚集的黑色素瘤患者进行了 BRCA1/2 基因的靶向测序，以探索黑色素瘤风险的分子基础。测序是在外周血中进行的。我们评估了 MutationTaster、Polyphen2、SIFT、PROVEAN 算法，分析了在两个有确定 BRCA2 变异的家族中（以及在一个家族中）与癌症疾病的分离，并在一个家族中进行了 LOH（基于 2 个原发性肿瘤）。我们在 BRCA1 中既没有发现致病性突变，也没有发现意义不明的变异。我们发现了两个意义不明的 BRCA2 变异：c.9334G>A 和 c.4534 C>T。通过对 1230 例连续黑色素瘤病例、5000 例乳腺癌患者、3500 例前列腺癌患者和 9900 例对照进行基因分型，评估了疾病等位基因频率。这两个变异在未经选择的癌症患者和健康对照中均未发现。MutationTaster、Polyphen2 和 SIFT 算法表明 c.9334G>A 是一种破坏性变异。由于缺乏肿瘤组织的 LOH 分析，因此无法对该变异进行分析。该变异与疾病分离。c.4534 C>T 变异与疾病不分离，该变异没有 LOH。c.9334G>A 变异，目前被归类为意义不明的罕见变异，可能导致乳腺癌、前列腺癌和黑色素瘤。需要进行功能研究以描述 DNA 变化如何影响蛋白质功能，以及进行大型多中心研究以评估其外显率。
