Objective  To detect the expressions of microRNA-185-5p (miR-185-5p) and SOX13 in cutaneous malignant melanoma (CMM) tissues, and to explore their clinical significance.

  Methods  A total of 61 CMM patients who underwent surgical treatment were selected as observation objects(CMM group), and another 61 tissue specimens diagnosed as benign pigmented nevi on the skin during the same period were selected as control group, according to the expression level of miR-185-5p in CMM tissues, CMM patients were divided into high miR-185-5p expression group(31 cases, miR-185-5p expression level ≥0.47) and low miR-185-5p expression group (30 cases, miR-185-5p expression level < 0.47). According to the results of SOX13 protein expression in CMM tissue, CMM patients were divided into SOX13 positive expression group (36 cases) and SOX13 negative expression group(25 cases). Quantitative real-time fluorescent polymerase chain reaction (qRT-PCR) method to detect the expression levels of miR-185-5p and SOX13 mRNA in CMM tissues and pigmented nevus tissues; immunohistochemical method was used to detect the expression level of SOX13 protein; Pearson method was used to analyze the correlation between miR-185-5p and SOX13 mRNA expression levels in CMM tissues; Kaplan-Meier survival curve was used to analyze the relationshipof the expressions of miR-185-5p and SOX13 with the survival rate of CMM patients; Cox regression model was used to analyze the prognostic influencing factors of CMM patients.

  Results  The expression level of miR-185-5p in CMM tissue was (0.47±0.08), which was significantly lower than (1.01±0.13) in pigmented nevus tissue (t=27.630, P < 0.05); the expression level of SOX13 mRNA in CMM tissue was significantly higher than that in pigmented nevus tissue(2.32±0.51) versus (1.05±0.11), t=19.012, P < 0.05; the positive expression rate of SOX13 protein in CMM tissue was significantly higher than that in pigmented nevus tissue (59.02% versus 13.11%, P < 0.05); there was a negative correlation between miR-185-5p and SOX13 mRNA expression in CMM tissues (r=-0.635, P < 0.05); the expressions of miR-185-5p and SOX13 in CMM tissue were related to the degree of invasion and lymph node metastasis (P < 0.05); the 3-year survival rate of the miR-185-5p high expression group was significantly higher than that of miR-185-5p low expression group (χ²=5.871, P=0.015); the 3-year survival rate of the SOX13 positive expression group was significantly lower than that of the SOX13 negative expression group (χ²=5.030, P=0.020); lymph node metastasis and SOX13 were independent risk factors for poor prognosis of CMM patients (P < 0.05), and miR-185-5p was a protective factor for poor prognosis of CMM patients (P < 0.05).

  Conclusion  The expression of miR-185-5p is low and the expression of SOX13 is high in CMM tissues. They are related to clinicopathological characteristics (such as lymph node metastasis) and prognosis in CMM patients, and may be used as potential prognostic markers of CMM.