To characterize BAP1's contribution to melanoma risk, we sequenced BAP1 in a set of 100 patients with OM, including 50 metastatic OM cases and 50 matched non-metastatic OM controls, and 200 individuals with cutaneous melanoma (CM) including 7 CM patients from CM-OM families and 193 CM patients from CM-non-OM kindreds.
In uveal melanoma, monosomy 3 is the most common genetic alteration and somatic mutations of BAP1, a tumor suppressor gene, have been reported in nearly 50% of primary uveal melanomas.
We then screened for germline BAP1 deleterious mutations in familial aggregations of cancers within the spectrum of the recently described BAP1-associated tumor predisposition syndrome, including uveal melanoma, malignant pleural mesothelioma, and cutaneous melanoma.
The finding expands on the growing profile of BAP1 as an important uveal and cutaneous melanoma tumor suppressor gene and implicates its involvement in the development of lung, and stomach cancer.
The clinical phenotype of BAP1 hereditary cancer predisposition syndrome (MIM 614327) includes uveal melanoma (UM), cutaneous melanoma (CM), renal cell carcinoma (RCC), and mesothelioma.
Inherited loss-of-function mutations in the BAP1 oncosuppressor gene are responsible for an inherited syndrome with predisposition to malignant mesothelioma (MM), uveal and keratinocytic melanoma, and other malignancies.
Combined BAP1 loss and BRAFV600E staining was seen in 67% of BAP1 tumor syndrome-associated lesions and in none of the sporadic melanocytic proliferations including Spitz and atypical Spitz nevi and atypical Spitz tumors, with the exception of 1 primary melanoma.
In addition, we recommend that testing of BAP1 should not be conducted routinely in CM families but should be reserved for families with CM and uveal melanoma, or mesothelioma.
Patients with heterozygous germline mutations in BRCA1-associated protein 1 (BAP1), a tumor suppressor gene, develop a tumor predisposition syndrome (OMIM 614327) with increased risk of uveal and cutaneous melanomas, cutaneous atypical and epithelioid melanocytic lesions, lung adenocarcinoma, clear cell renal cell carcinoma, and other tumors.
Patients with germline BAP1 mutations exhibited increased frequency of family history of cancer (100% vs 65.9%, P = .06), particularly cutaneous melanoma (62.5% vs 9.9%, P < .001) and ocular melanoma (25.0% vs 1.9%, P = .01).
The coexistence of dysplastic nevus syndrome and a BAP1 germline mutation extends the spectrum of the BAP1 tumor predisposition syndrome and may confer a greater risk for cutaneous melanomas.
Moreover, many tumors harboring BAP1 germline mutations were associated with BAP1 syndrome, including mesothelioma and ocular/cutaneous melanomas, as well as renal, breast, lung, gastric, and basal cell carcinomas.
Various features that are unique to specific disorders, such as the appearance of melanocytic BAP1-mutated atypical intradermal tumors in cases of BAP1melanoma syndrome, should also be recognized early.
While many uveal melanomas harbor mutations in the BRCA-Associated Protein 1 (BAP1) gene, the genetics of non-BAP1 associated tumors are not completely understood.
Our study suggests that CDKN2A, in addition to BAP1, could be involved in the melanoma and mesothelioma susceptibility, leading to the rare familial cancer syndromes.
Germline BAP1 mutations cause a novel cancer syndrome characterised by early onset of multiple atypical Spitz tumours and increased risk of uveal and cutaneous melanoma, mesothelioma, renal cell carcinoma and various other malignancies.
Two of these three probands carrying BAP1 loss-of-function variants also had melanomas with histopathological features suggestive of a germline BAP1 mutation.
The recent technological advances have allowed the identification of new genes involved in melanoma susceptibility: breast cancer 1 (BRCA1), BRCA1-associated protein 1 (BAP1), and telomerase reverse transcriptase (TERT).Tests on these genes allow to identify a larger number of high-risk individuals with a potential of developing familial melanoma and primary multiple melanomas.
Our findings suggest that the genetic profile of coexistent GNAQ or GNA11 mutations with BAP1 or SF3B1 mutations can aid the histopathological diagnosis of blue nevus-like melanoma and distinguish blue nevus-like melanoma from conventional epidermal-derived melanomas.