Association of ocular melanoma with breast cancer but not with cutaneous melanoma: results from the Swedish Family-Cancer Database

Implementation of BRCA mutations testing in formalin-fixed paraffin-embedded (FFPE) samples of different cancer types

BRCA1 and BRCA2 are onco-suppressor genes involved in the DNA repair mechanism. The presence of BRCA1/2 mutations confers a higher risk of developing several cancer types. To date, the FDA approved various PARP inhibitors to treat selected BRCA1/2 mutated oncologic patients. At first, PARP inhibitors were approved for patients with ovarian and breast cancers, and subsequently for metastatic pancreatic adenocarcinoma and metastatic castration-resistant prostate cancer after the treatment with chemotherapy. The current guidelines for BRCA testing are very heterogeneous between the different types of tumors regarding the diagnostic algorithm and the type of sample to analyze, such as the blood for the germline mutations and the tumoral tissue for the somatic mutations. Few data have currently been described regarding the detection of BRCA1/2 somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. In this review, we propose an overview of the BRCA mutations in FFPE samples of several cancers, including breast, ovarian, fallopian tube, primary peritoneal, prostate, and pancreatic cancer. We summarize the types and the frequency of BRCA mutations, the guidelines approved for the test, the molecular assays used for the detection and the PARP inhibitors approved for each tumor type.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

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.

Germline BAP1 alterations in familial uveal melanoma

Uveal melanoma (UM) is the most commonly diagnosed primary intraocular tumor in adults. Familial UM (FUM), defined as two or more family members diagnosed with UM, is rare and estimated at less than 1% of all UM. Currently, BAP1 is the only gene known to contribute significant risk for UM. In this study we aimed to estimate the frequency of BAP1 mutation in FUM and to characterize the family and personal histories of other cancers in these families. We identified 32 families with FUM, including seven families previously reported by our group. BAP1 mutation testing was carried out by direct sequencing of the coding exons and the adjacent untranslated regions of the gene. Germline deletion and duplication analysis of BAP1 was assessed by multiplex ligation-dependent probe amplification (MLPA). Germline BAP1 mutations were found in 6/32 (19%) families. No deletions or duplications were identified in any of the 24 samples tested by MLPA. Combined with published studies, the frequency of BAP1 mutations was 14/64 (22%) in FUM. FUM families without BAP1 mutations have distinct family histories with high rates of prostate cancer in first- and second-degree relatives. It is likely that additional genes conferring risk for FUM exist. It is important to understand key shared features of FUM to focus future research on identifying these additional tumor predisposition syndromes. Though BAP1 should be tested first in these families, FUM families without BAP1 mutation should be explored for additional predisposition genes. © 2016 Wiley Periodicals, Inc.

Hormonal exposures and the risk of uveal melanoma

OBJECTIVES

Several studies suggest that hormonal mechanisms may be associated with the development of uveal melanoma. Therefore, the association between the risk of uveal melanoma and exposure to hormonal exposures was investigated in a case-control study from nine European countries.

METHODS

Incident cases of uveal melanoma were frequency-matched to population and hospital controls by country, age, and sex. Female subjects were asked about their reproductive history, use of menopausal hormone replacement therapy and oral contraceptives. Among men, occupational handling of oils while working with transformers or capacitors which contain polychlorinated biphenyls (PCB) was solicited. Unconditional logistic regression analyses were calculated, adjusting for several potential confounders. Analyses were stratified by sex.

RESULTS

Two hundred and ninety-three cases (165 men, 128 women) and 3,198 control subjects (2,121 men, 1,077 women) were interviewed. Among women, no associations were observed with hormonal status variables, intake of hormonal therapy or intake of oral contraceptives. Men showed an increased risk with occupational exposure to transformer/capacitor oils (OR = 2.74; Bonferroni-corrected 99.3% CI 1.07-7.02). However, these results were based on few exposed subjects only.

CONCLUSION

The results of this study do not support the hypothesis of a hormonal influence in the carcinogenesis of uveal melanoma. Our finding of a potentially increased risk with PCB-containing oils requires further research.

Familial risks for eye melanoma and retinoblastoma: results from the Swedish Family-Cancer Database

No systematic population-based studies have been conducted on familial eye cancers. Reliable data on familial risks are important for clinical counselling and cancer genetics. The current analysis was based on the nation-wide Swedish Family-Cancer Database on 10.5 million individuals, containing families with parents and offspring. Cancer data were retrieved from the Swedish Cancer Registry from the years 1958 to 2002, including 3636 patients with any type of eye cancer. Familial risk for offspring was defined using the standardized incidence ratio (SIR), adjusted for many variables. Ocular melanoma was detected in two parent-offspring pairs, but the SIR of 3.90 was not significant. Parental upper aerodigestive tract (2.05), left-sided colon (1.83) and male non-medullary thyroid (6.98) cancers showed an association with ocular melanoma, albeit some with a borderline significance. The SIR for leukaemia was increased when parents were diagnosed with eye melanoma. There was no evidence for the association of ocular melanoma with cutaneous melanoma. The SIR for ocular melanoma was 1.76 when a sister was diagnosed with breast cancer, but there was no increase when a mother was diagnosed with breast cancer. When both a child and the parent presented with retinoblastoma, the SIR was 900. The parents of children with retinoblastoma had an excess of small intestinal and rectal cancers and Hodgkin's disease. The present findings were based on a limited number of cases, but they display a complex and heterogeneous pattern of familial associations in ocular melanoma, including an association with breast cancer through a putative recessive mechanism.

Associations between ocular melanoma and other primary cancers: An international population-based study

Ocular melanoma is a rare neoplasm with a poorly understood etiology, especially concerning its link with ultraviolet-light exposure. Studying the risk of second primary cancers may help to formulate causal hypotheses. We used data from 13 cancer registries, including 10,396 first occurring ocular melanoma cases, and 404 second occurring cases. To compare the second cancer incidence in ocular melanoma patients to that in noncancer population, we calculated standardized incidence ratios (SIRs) of 32 types of cancer. We also calculated SIRs of second ocular melanoma after other primaries. Ocular melanoma patients had significantly increased risk of cutaneous melanoma (SIR = 2.38, 95% CI 1.77-3.14), multiple myeloma (SIR = 2.00, 1.29-2.95), and of liver (SIR = 3.89, 2.66-5.49), kidney (SIR = 1.70, 1.22-2.31), pancreas (SIR = 1.58, 1.16-2.11), prostate (SIR = 1.31, 1.11-1.54), and stomach (SIR = 1.33, 1.03-1.68) cancers. Risks of cutaneous melanoma were highly variable between registries and were mainly increased in females, in younger patients, in first years following diagnosis, and for patients diagnosed after 1980. The risk of ocular melanoma was significantly increased only after prostate cancer (SIR = 1.41, 1.08-1.82). Risk of cutaneous melanoma after ocular melanoma had epidemiological patterns, similar to cutaneous melanoma screening in the general population. The increased risk of cutaneous melanoma would be largely due to greater skin cancer surveillance in ocular melanoma patients, and not to common etiological factors. The high SIR found for liver cancer may be explained by misclassification bias. Common etiological factors may be involved in ocular and prostate cancers.

Incidence of noncutaneous melanomas in the U.S

BACKGROUND

Description of the epidemiology of noncutaneous melanoma has been hampered by its rarity. The current report was the largest in-depth descriptive analysis of incidence of noncutaneous melanoma in the United States, using data from the North American Association of Central Cancer Registries.

METHODS

Pooled data from 27 states and one metropolitan area were used to examine the incidence of noncutaneous melanoma by anatomic subsite, gender, age, race, and geography (northern/southern and coastal/noncoastal) for cases diagnosed between 1996 and 2000. Percent distribution by stage of disease at diagnosis and histology were also examined.

RESULTS

Between 1996 and 2000, 6691 cases of noncutaneous melanoma (4885 ocular and 1806 mucosal) were diagnosed among 851 million person-years at risk. Ocular melanoma was more common among men compared with women (6.8 cases per million men compared with 5.3 cases per million women, age-adjusted to the 2000 U.S. population standard), whereas mucosal melanoma was more common among women (2.8 cases per million women compared with 1.5 cases per million men). Rates of ocular melanoma among whites were greater than eight times higher than among blacks. Rates of mucosal melanoma were approximately two times higher among whites compared with blacks.

CONCLUSIONS

In contrast to cutaneous melanoma, there was no apparent pattern of increased noncutaneous melanoma among residents of southern or coastal states, with the exception of melanoma of the ciliary body and iris. Despite their shared cellular origins, both ocular and mucosal melanomas differ from cutaneous melanoma in terms of incidence by gender, race, and geographic area.

Familial invasive and in situ squamous cell carcinoma of the skin

We used the updated nation-wide Swedish Family-Cancer Database to examine familial risks in data from 1961 to 1998 on 1252 invasive and 2474 in situ squamous cell carcinoma (SCC) of the skin among offspring, and over 10 times more among parents. In 259 families a parent and an offspring had skin SCC. The familial standardised incidence ratios (SIRs) were 2.72 for invasive and 2.40 for in situ skin cancers in offspring. Multiple skin cancers in parents were associated with increased SIRs for invasive SCC in offspring, being 2.55 for one and up to 14.93 for two invasive and two in situ cancers in parents; the corresponding in situ SCC risks were 2.28 and 7.49. The population attributable fraction for any familial skin SCC, invasive or in situ, was 4.1%. Melanoma was the only discordant tumour that was associated with invasive and in situ skin SCC. These results provide evidence that there is an underlying hereditary susceptibility for at least a part of the familial clustering for skin SCC.