Commonly, in patients with melanoma metastases of an unknown primary tumor (MUP), an extensive search for the primary tumor is carried out. Recently, highly recurrent telomerase reverse transcriptase (TERT)-promoter mutations were found in malignant melanomas, which may function as driver mutations of skin cancer. The aim of this study was to test the hypothesis that MUP and mucosal melanomas harbor different prevalences of TERT-promoter mutations. Thirty-nine patients with MUP and 53 patients with mucosal melanomas were retrieved. In total, 152 paraffin samples of 92 patients were analyzed, and in 38 patients, multiple samples were tested. Mutational analysis of the TERT-promoter, BRAF, NRAS, and KIT genes was carried out. In total, 92 patients were eligible for mutational analysis. TERT-promoter mutations were found in 33 patients (35.9%): chr5, 1,295,228 C>T (18 patients); chr5, 1,295,250 C>T (11 patients); chr5, 1,295,228-229 CC>TT (three patients); chr5, 1,295,242-243 CC>TT (one patient). The mutations were significantly more prevalent in MUP [26 (66.7%)] than in mucosal melanomas [seven patients (13.2%); P<0.001]. In MUP, BRAF mutations were found in 46.2% of patients (18 patients) and NRAS mutations in 28.2% of patients (11 patients). In mucosal melanoma, NRAS mutations were found in 18.9% of patients (10), and BRAF and KIT mutations in 7.5% of patients (four patients), respectively. The prevalence of TERT-promoter mutations was associated with the patient's sex [23 (51.1%) men, 10 (21.3%) women; P=0.004]. No significant correlation was found between TERT-mutation and patient survival. The TERT-promoter genotype of MUP points toward a cutaneous and not mucosal origin. The significant sex differences merit further attention in having putative therapeutic implications.
Melanoma/genetics , Neoplasms, Unknown Primary/genetics , Telomerase/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Female , Genotype , Humans , Male , Melanoma/metabolism , Melanoma/pathology , Middle Aged , Mutation , Neoplasms, Unknown Primary/metabolism , Neoplasms, Unknown Primary/pathology , Sex Factors , Telomerase/metabolism , Young Adult
Approximately 50% of mucosal melanomas affect the head and neck region representing approximately 9% of all malignant head and neck tumors. The pathogenesis of this disease is unknown. Mucosal melanomas are characterized by an aggressive biological behavior, leading to a 5-year survival rate of less than 25%. Data for this review were identified by searches of Medline, Current Contents, PubMed, and references from relevant articles using the terms 'mucosal melanoma,' 'head and neck melanoma,' 'c-kit mutation in melanoma,' and 'c-kit inhibitors'. Therapy aims for the complete surgical excision of the primary tumor, whereas sentinel node biopsy is not established and present data do not support the addition of radiotherapy. Mutilating operations of larger tumors should be avoided, as they do not inhibit the frequent development of distant metastasis. C-kit mutations and amplifications are found in approximately 15-30% of mucosal and acral-lentiginous melanomas. Therefore, the use of so-called targeted therapies addressing molecular structures in mucosal melanomas seem to represent new promising treatment tools. In this study, we review the literature regarding epidemiology, molecular pathology, and therapy of mucosal melanomas of the head and neck emphasizing c-kit protein inhibiting treatment modalities for tumors carrying c-kit mutations.
Head and Neck Neoplasms/diagnosis , Head and Neck Neoplasms/therapy , Melanoma/diagnosis , Melanoma/therapy , Protein Kinase Inhibitors/therapeutic use , Antineoplastic Agents/therapeutic use , Head and Neck Neoplasms/epidemiology , Head and Neck Neoplasms/genetics , Head and Neck Neoplasms/pathology , Humans , Melanoma/epidemiology , Melanoma/pathology , Mucous Membrane/pathology , Mutation , Prognosis , Proto-Oncogene Proteins c-kit/antagonists & inhibitors , Radiotherapy/methods , Surgical Procedures, Operative/methods
