Abstract: Uveal melanoma (UM) is the most common malignant eye tumor in adults affecting ~7,000 individuals per year worldwide. UM is a rare subtype of melanoma with distinct clinical and molecular features as compared to other melanoma subtypes. UMs lack the most typical cutaneous melanoma-associated mutations ( BRAF , NRAS , and NF1 ) and are instead characterized by a different set of genes with oncogenic or loss-of-function mutations. By next-generation sequencing efforts on UM tumors, several driver genes have been detected. The most frequent ones are BAP1 , EIF1AX , GNA11 , GNAQ , and SF3B1 . In many cases, mutations in these genes appear in a mutually exclusive manner, have different risk of metastasis, and are consequently of prognostic importance. The majority of UM cases are sporadic but a few percentage of the cases occurs in families with an inherited predisposition for this malignancy. In recent years, germline mutations in the BAP1 gene have been found to segregate in an autosomal dominant pattern with numerous different cancer types including UM in cancer-prone families. This cancer syndrome has been denoted as the tumor predisposition syndrome. Keywords: uveal melanoma, driver genes, oncogenes, tumor suppressor genes, familial cancer
Germline CDKN2A mutations are found in 5–20% of melanoma families. Numerous studies have shown that carriers of CDKN2A mutations have increased risks of non‐melanoma cancers, but so far there have been no studies investigating cancer risks in CDKN2A wild type (wt) melanoma families. In this prospective cohort study, index melanoma cases ( n = 224) and their first‐degree relatives ( n = 944) were identified from 154 confirmed CDKN2A wt melanoma families. Cancer diagnoses in family members and matched controls were obtained from the Swedish Cancer Registry. Relative risks (RR), odds ratios (OR) and two‐sided 95% confidence intervals (95% CI) were calculated. In index cases and first‐degree relatives, the prospective RR for melanoma was 56.9 (95% CI 31.4–102.1) and 7.0 (95% CI 4.2–11.4), respectively, and for squamous cell skin cancers 9.1 (95% CI 6.0–13.7) and 3.4 (95% CI 2.2–5.2), respectively. In neither group, elevated risks were seen for non‐skin cancers. In a subgroup analysis, CDKN2A wt melanoma families with young (<40 years) melanoma cases were found to have increased risk of non‐skin cancers (RR 1.5, 95% CI 1.0–1.5). Further, MC1R gene variants were increased in familial melanoma cases compared to controls (OR 2.4, 95% CI 1.6–3.4). Our findings suggest that in the majority of CDKN2A wt melanoma families, a segregation of variants in low‐risk melanoma genes such as MC1R causes increased skin cancer susceptibility, rather than mutations in high‐risk cancer predisposing genes, such mutations are more probable to be found in melanoma families with young melanoma cases. This study further supports an implication of CDKN2A mutation screening as a clinical test that determines counseling and follows up routines of melanoma families.
Abstract Cutaneous melanoma (CM) is rare in children, representing 1-3% of all paediatric malignancies and occurring at a frequency of 0.3-0.4% before puberty. MC1R is a key gene for skin pigmentation and is highly polymorphic in Caucasians. MC1R gene variants are associated with CM in different populations, and with congenital melanocytic naevi in children. The aim of this study is to evaluate whether the prevalence of MC1R variants differed among sporadic childhood and adolescent CM cases compared to adult patients. Data were gathered through the M-SKIP project, an international pooled-analysis on MC1R variants, skin cancer and phenotypic characteristics. CM cases with information on age at diagnosis were selected from the M-SKIP dataset and divided into three groups: childhood (age ≤14 years, N=13), adolescent (age 15 to 18 years, N=52) and adult (age > 18 years, N=7,696). The frequency of carrying specific MC1R variants as well as at least one MC1R variant were compared between childhood/adolescent and adult CM cases with Chi Square test. The prevalence of any MC1R variant was lower in children (≤14 years, 63%) than in adolescents (15-18 years, 71%) or adults (>18 years, 75%), although overall the difference was not statistically significant. A higher prevalence of the MC1R V92M variant was found in childhood and adolescent compared to adult CM cases (23% vs 5%, p=0.06). In contrast, the MC1R R151C variant was found less frequently in childhood and adolescent than in adult cases (9% vs 18%, p=0.06). Looking at rare variants in 5,983 cases with MC1R sequenced, 3 (9%) carriers of MC1R ins86A were found among 32 childhood and adolescent patients, while only 44 (1%) carriers of the same variant were found among 5,951 adult cases (p<0.0001). MC1R variants ins86A and V92M, but not R151C, may be specifically associated with childhood and adolescent melanoma. Further studies using a larger sample size is needed to validate the present findings. Citation Format: Sara Raimondi, Sara Gandini, Peter A. Kanetsky, Veronica Hoiom, Rajiv Kumar, Paola Ghiorzo, Tadeusz Debniak, Ricardo Fernandez de Misa, Giuseppe Palmieri, Jiali Han, Maria Teresa Landi, Terry Dwyer, Maria Concetta Fargnoli, Wojciech Branicki, Nelleke A. Gruis, Alexander Stratigos, Gloria Ribas, M. Laurin Council, Manfred Kayser, Philippe Autier, Jose Carlos García-Borrón, Julian Little, Julia Newton-Bishop, Francesco Sera, Eduardo Nagore. Role of MC1R variants in childhood and adolescent melanoma. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A38.
Background Inherited CDKN2A mutation is a strong risk factor for cutaneous melanoma. Moreover, carriers have been found to have poor melanoma-specific survival. In this study, responses to novel immunotherapy agents in CDKN2A mutation carriers with metastatic melanoma were evaluated. Methods CDKN2A mutation carriers that have developed metastatic melanoma and undergone immunotherapy treatments were identified among carriers enrolled in follow-up studies for familial melanoma. The carriers’ responses were compared with responses reported in phase III clinical trials for CTLA-4 and PD-1 inhibitors. From publicly available data sets, melanomas with somatic CDKN2A mutation were analysed for association with tumour mutational load. Results Eleven of 19 carriers (58%) responded to the therapy, a significantly higher frequency than observed in clinical trials (p=0.03, binomial test against an expected rate of 37%). Further, 6 of the 19 carriers (32%) had complete response, a significantly higher frequency than observed in clinical trials (p=0.01, binomial test against an expected rate of 7%). In 118 melanomas with somatic CDKN2A mutations, significantly higher total numbers of mutations were observed compared with 761 melanomas without CDKN2A mutation (Wilcoxon test, p<0.001). Conclusion Patients with CDKN2A mutated melanoma may have improved immunotherapy responses due to increased tumour mutational load, resulting in more neoantigens and stronger antitumorous immune responses.
Dabrafenib is an inhibitor of BRAF V600E used for treating metastatic melanoma but a majority of patients experience adverse effects. Methods to measure the levels of dabrafenib and major metabolites during treatment are needed to allow development of individualized dosing strategies to reduce the burden of such adverse events. In this study, an LC-MS/MS method capable of measuring dabrafenib quantitatively and six metabolites semi-quantitatively is presented. The method is fully validated with regard to dabrafenib in human plasma in the range 5–5000 ng/mL. The analytes were separated on a C18 column after protein precipitation and detected in positive electrospray ionization mode using a Xevo TQ triple quadrupole mass spectrometer. As no commercial reference standards are available, the calibration curve of dabrafenib was used for semi-quantification of dabrafenib metabolites. Compared to earlier methods the presented method represents a simpler and more cost-effective approach suitable for clinical studies.
Little is known on whether melanocortin 1 receptor (MC1R) associated cutaneous melanoma (CM) risk varies depending on histological subtype and body site, and whether tumour thickness at diagnosis (the most important prognostic factor for CM patients) differs between MC1R variant carriers and wild-type individuals. We studied the association between MC1R variants and CM risk by histological subtype, body site, and Breslow thickness, using the database of the M-SKIP project. We pooled individual data from 15 case-control studies conducted during 2005-2015 in Europe and the USA. Study-specific, multi-adjusted odds ratios were pooled into summary odds ratios (SOR) and 95% confidence intervals (CI) using random-effects models. Six thousand eight hundred ninety-one CM cases and 5555 controls were included. CM risk was increased among MC1R variant carriers vs. wild-type individuals. The increase in risk was comparable across histological subtypes (SOR for any variant vs. wild-type ranged between 1.57 and 1.70, always statistical significant) except acral lentiginous melanoma (ALM), for which no association emerged; and slightly greater on chronically (1.74, 95% CI 1.47-2.07) than intermittently (1.55, 95% CI 1.34-1.78) sun-exposed skin. CM risk was greater for those carrying 'R' vs. 'r' variants; correlated with the number of variants; and was more evident among individuals not showing the red hair colour phenotype. Breslow thickness was not associated with MC1R status. MC1R variants were associated with an increased risk of CM of any histological subtype (except ALM) and occurring on both chronically and intermittently sun-exposed skin.
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