[Multiple neoplasms in patients with uveal melanoma]

Additional primary malignancies in a Polish cohort of uveal melanoma patients: a review of 644 patients with long-term follow-up

AIM

To investigate the frequency and location of additional primary malignancies in a Polish cohort of uveal melanoma (UM) patients registered in a single centre database.

MATERIAL AND METHOD

Retrospective data analysis of patients treated for uveal melanoma at the Department of Ophthalmology, Poznań University of Medical Sciences, Poland between 1991 and 2017. Data on the diagnosis of the additional malignancies were obtained during the follow-up visits in our Department and/or from the Greater Poland Cancer Registry. The exclusion criteria comprised no confirmed follow-up or incomplete clinical entry data.

RESULTS

Among 644 UM patients registered in the database up to 2017, the additional malignancy was diagnosed in 126 (20%) patients: 71 men, 55 women at the median age of 67 years (range: 34-94). In 48 patients (38%), the additional malignancy occurred prior to the diagnosis of UM, in 73 (58%) patients - after it. The most common locations of second cancer were skin (20 cases / 15%), breast (17 cases / 13%) and lungs (15 cases / 12%). The median follow-up was 36 months (range: 3-242). 87 patients (69%) died by the study close, 32 (37%) of them due to metastatic disease from uveal melanoma, 41 (47%) due to another cancer.

CONCLUSIONS

The frequency of additional primary malignancies was higher in our cohort than reported by most of other groups. If there is a certain predisposition to a specific type of additional primary carcinoma in UM patients, the analysis of larger database is required.

Evaluation of the contribution of germline variants in BRCA1 and BRCA2 to uveal and cutaneous melanoma

Germline mutations of BRCA1 and BRCA2 predispose individuals to a high risk of breast and ovarian cancer, and elevated risk of other cancers, including those of the pancreas and prostate. BRCA2 mutation carriers may have increased risk of uveal melanoma (UM) and cutaneous melanoma (CM), but associations with these cancers in BRCA1 mutation carriers have been mixed. Here, we further assessed whether UM and CM are associated with BRCA1 or BRCA2 by assessing the presence, segregation and reported/predicted pathogenicity of rare germline mutations (variant allele frequency < 0.01) in families with multiple members affected by these cancers. Whole-genome or exome sequencing was performed on 160 CM and/or UM families from Australia, the Netherlands, Denmark and Sweden. Between one and five cases were sequenced from each family, totalling 307 individuals. Sanger sequencing was performed to validate BRCA1 and BRCA2 germline variants and to assess carrier status in other available family members. A nonsense and a frameshift mutation were identified in BRCA1, both resulting in premature truncation of the protein (the first at p.Q516 and the second at codon 91, after the introduction of seven amino acids due to a frameshift deletion). These variants co-segregated with CM in individuals who consented for testing and were present in individuals with pancreatic, prostate and breast cancer in the respective families. In addition, 33 rare missense mutations (variant allele frequency ranging from 0.00782 to 0.000001 in the aggregated ExAC data) were identified in 34 families. Examining the previously reported evidence of functional consequence of these variants revealed all had been classified as either benign or of unknown consequence. Seeking further evidence of an association between BRCA1 variants and melanoma, we examined two whole-genome/exome sequenced collections of sporadic CM patients (total N = 763). We identified one individual with a deleterious BRCA1 variant, however, this allele was lost (with the wild-type allele remaining) in the corresponding CM, indicating that defective BRCA1 was not a driver of tumorigenesis in this instance. Although this is the first time that deleterious BRCA1 mutations have been described in high-density CM families, we conclude that there is an insufficient burden of evidence to state that the increased familial CM or UM susceptibility is because of these variants. In addition, in conjunction with other studies, we conclude that the previously described association between BRCA2 mutations and UM susceptibility represents a rare source of increased risk.