DLEC1 has been suggested as a tumor suppressor gene in several cancers. DLEC1 D215N somatic mutation (COSM36702) was identified in a melanoma cell line through whole genome sequencing. However, little is known about the implication and prevalence of this mutation in primary melanomas or in melanocytic nevi. The aim of this study was to genotype DLEC1 D215N mutation in melanoma tissue and melanocytic nevi samples to confirm its occurrence and to estimate its prevalence. Primary melanomas ( ) paired with synchronous or asynchronous metastases ( ) from 81 melanoma patients and melanocytic nevi ( ) were screened for DLEC1 D215N mutation. We found the mutation in 3 primary melanomas and in 2 melanocytic nevi, corresponding to a relatively low prevalence (3.7% and 7.1%, resp.). The pathogenic role of DLEC1 215N mutation is unclear. However, since the mutation has not been previously described in general population, its involvement in nevogenesis and melanoma progression remains a possibility to be clarified in future studies. 1. Introduction Mutations in deleted in lung and esophageal cancer 1 (DLEC1) gene or its inactivation by epigenetic silencing, namely, promoter CpG island hypermethylation or histone hypoacetylation, were previously reported in several cancers (lung [1], esophagus [2], kidney [3], stomach [4], colon [4], ovary [5], breast [6], head and neck [7], and lymphoma [8]). Furthermore, a negative impact on the prognosis related with DLEC1 inactivation was demonstrated in lung [9], kidney [10], and ovary [5] carcinomas. DLEC1 D215N mutation (COSM36702) is a substitution in codon 641 (ENST00000308059) which was identified in whole genome sequencing of a tumor cell line derived from melanoma metastases [11]. To establish the catalogue of somatic mutations in cancer cells, a lymphoblastoid line derived from the same patient was also sequenced [11]. Three different missense mutations were found in other genome or exome sequencing studies, making DLEC1 a candidate tumor suppressor gene in cutaneous melanoma, probably acting by inhibition of cell proliferation [12, 13]. Nevertheless, the prevalence of DLEC1 mutations among primary melanomas, melanoma metastases, or benign melanocytic nevi remains undetermined. The aim of this study was to confirm the occurrence and estimate the prevalence of DLEC1 D215N mutation in formalin fixed and paraffin embedded tissue samples from melanoma and melanocytic nevi. 2. Patients and Methods 2.1. Melanoma Patients In all, 102 formalin fixed paraffin embedded tumor tissues from 81 patients with melanoma were screened.
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