Abstract: Objective To investigate the effects of PTEN (phosphatase and tensin homolog)mutation on pathological characteristics and prognosis of patients with mucosal melanoma. Methods Clinical and follow-up data of 66 patients with mucosal melanoma from the Department of Melanoma and Sarcoma, Peking University Cancer Hospital from April 2019 to March 2022 were collected and the mutation of PTEN was detected by next-generation sequencing to analyze the relationship between PTEN mutation and patients′ pathological characteristics and prognosis. Results Among 66 patients with mucosal melanoma, the frequency of PTEN mutation was 19.40% and the mutation frequency was significantly associated with age at diagnosis and primary tumor site(P＜0.05); In the cohort with 42 patients receiving immunotherapy, the median progression-free survival(mPFS) of PTEN-mutant patients was 3.37 months, which was significantly lower than that of wild-type patients(9.2 months)(P＜0.05). Multivariate Cox regression analysis further confirmed that PTEN mutation was an independent prognostic factor for poor prognosis of immunotherapy(P＜0.05). Conclusions The frequency of PTEN mutation is significantly higher in patient who were diagnosed at the aged less than 60 and in patients with tumors originated from gastrointestinal mucosa. PTEN mutation is also an independent risk factor for poorer prognosis in patients receiving immunotherapy.

Key words: mucosal melanoma, PTEN, gene mutation, pathological feature, prognosis