Abstract: Song Hao, Bu Wenbo, Ni Nana, Wen Sijian, Xiong Jingshu, Qi Jinliang, Xu Xiulian, Sun Jianfang Department of Pathology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China （Song H, Ni NN, Wen SJ, Xiong JS, Xu XL, Sun JF）; Department of Dermatologic Surgery, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China （Bu WB）; State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China （Qi JL） Corresponding authors: Xu Xiulian, Email: xxlqjl@sina.com; Sun Jianfang, Email: fangmin5758@aliyun.com 【Abstract】 Objective To explore the miRNA regulating the potential cancer-promoting gene CCL18 in cutaneous malignant melanoma. Methods Bioinformatics analysis was conducted by using online software miRanda and TargetScan, so as to predict the miRNA targeting CCL18 gene. Three kinds of CCL18 3′UTR dual-luciferase reporter vectors, including mutant 3′UTR vector （mutant 3′UTR group）, wild-type 3′UTR vector （wild-type 3′UTR group） and empty vector （blank control group）, as well as miRNA vectors carring selected miRNAs were constructed according to human gene sequence analysis, and then were used to co-transfect 293T cells. After 48-hour treatment, the cells were lysed for detection of luciferase activity. Real-time fluorescence-based quantitative PCR was performed to measure the of CCL18 and selected miRNA in 14 fresh malignant melanoma tissue specimens and 14 paracancerous normal skin tissue specimens （control tissues）, and their correlations were analyzed. Results Online software analysis showed that some miRNAs were identified to target the 3′UTR of CCL18 gene, including miR-183, miR-128 and miR-33a. Luciferase reporter vectors and miRNA vectors were constructed successfully. As luciferase activity assay showed, when miR-183 and miR-128 were bound to the CCL18 3′UTR, the luciferase activities were significantly higher in their mutant 3′UTR groups （11.63 ± 0.42; 8.80 ± 0.49） than in their wild-type 3′UTR groups （4.86 ± 0.39; 5.01 ± 0.54; both P < 0.05） and blank control groups （2.41 ± 0.13; 2.39 ± 0.05; both P < 0.01）, while there were no significant differences between miR-33a-binding mutant 3′UTR group （6.41 ± 0.47） and miR-33a-binding wild-type 3′UTR group （6.16 ± 0.22, P > 0.05）. Real-time fluorescence-based quantitative PCR revealed higher mRNA of the CCL18 gene （3.52 ± 1.68）, but lower of miR-183 （0.49 ± 0.32）, miR-128 （0.30 ± 0.20） and miR-33a （0.46 ± 0.40） in the malignant melanoma tissues compared with the control tissues. The mRNA of the CCL18 gene was negatively correlated with the of miR-128 （rs = -0.548, P < 0.05）, but showed no significant correlations with the of miR-183 and miR-33a （both P > 0.05）. Conclusion miR-128 may play a role in regulating the potential malignant melanoma-promoting gene CCL18.