RESUMO
BACKGROUND: Acral melanoma occurs on glabrous skin or the nail apparatus and is distinct from ultraviolet-related melanoma due to differing genetic alteration patterns. Although the pathogenesis of acral melanoma is not well understood, mechanical stress is thought to induce acral melanoma. The incidence of gene mutation and promoter methylation has been reported in tumors from acral melanoma; however, an association between genetic/epigenetic alterations and mechanical stress in acral melanoma remains unclear. OBJECTIVE: To investigate the relationship between clinical/genetic factors and mechanical stress in acral melanoma. METHODS: A retrospective review of 52 patients diagnosed with acral melanoma was performed. We reviewed the clinical characteristics of patients, tumor status, and tumor location. Mutations in BRAF, NRAS, and the TERT promoter, along with KIT amplification and PTEN promoter methylation were analyzed in the tumors. RESULTS: The heel (34/52, 65.4%) was the most common anatomical tumor site. Mutations in BRAF (6/48, 12.5%), NRAS (6/49, 12.2%), and the TERT promoter (4/33, 12.1%), along with KIT amplification (3/37, 8.1%) and PTEN promoter hypermethylation (12/48, 25.0%) were observed in the tumors. On the forefoot, heel, and hallux, PTEN promoter hypermethylation was significantly associated with Breslow thickness (p=0.001) and ulceration rate (p=0.042). On the midfoot and lesser toes, there was no significant difference in Breslow thickness or ulceration rate regardless of PTEN promoter hypermethylation (p>0.05). CONCLUSION: PTEN promoter hypermethylation is associated with Breslow thickness and tumor ulceration on the forefoot, heel, and hallux in acral melanoma in Korean patients.
RESUMO
BACKGROUND/AIM: Melanoma-associated antigen A12 (MAGEA12) has recently been reported as a repressor of tumor-suppressor genes. This study aimed to investigate the implications of MAGEA12 expression in the pathogenesis of cutaneous squamous cell carcinoma (cSCC). MATERIALS AND METHODS: MAGEA12 and p21 expression were investigated in 15 samples of normal skin and 111 of cSCC tissues by immunohistochemistry. The biological functions of MAGEA12 in cSCC were also investigated both in vitro and in vivo. RESULTS: Expression of both MAGEA12 and p21 was significantly increased in cSCC. MAGEA12 expression showed a positive correlation, while p21 expression showed negative correlation with the recurrence-free survival of patients with cSCC. In addition, MAGEA12 knockdown significantly attenuated proliferative, migratory, invasive, and tumorigenic activities of cSCC cells and was negatively correlated with p21 expression both in vitro and in vivo. CONCLUSION: MAGEA12-mediated down-regulation of p21 may be involved in cSCC pathogenesis and MAGEA12 may serve as a molecular biomarker in cSCC.
