Abstract: XU Sheng-jing*, RAO Yan-ting, ZHAO Zhi-guo, YIN Xue-feng, ZHANG Cai-ping, MA Chao-dong, ZHANG Yu, CHEN Jian-hua, DING Ke-yun. *Department of Dermatology, Affiliated People's Hospital of Jiangsu University, Zhenjiang 212002, Jiangsu, China Corresponding author: DING Ke-yun, Email: dingkeyun123@163.com 【Abstract】 Objective To detect the expressions of CD99 and miRNAs in dermatofibrosarcoma protuberan （DFSP） and dermatofibroma （DF）, and to investigate their clinical implications. Methods This study included 30 DFSP and 15 DF paraffin-embedded tissue specimens collected at the Department of Pathology, Affiliated People's Hospital of Jiangsu University, from January 2002 to December 2010, as well as two DFSP and three DF fresh-frozen tissue specimens. The expression of CD99 was detected by immunohistochemistry in all of these paraffin-embedded specimens, and by Western blot in one DFSP and two DF fresh-frozen tissue specimens. Real-time PCR was carried out to determine the expression levels of miR-637, miR-576-5p, miR-23a, miR-23b, miR-625 and miR-205 in two DFSP and three DF fresh-frozen tissue specimens. Immunohistochemical results were compared by chi-square test. Results Immunohistochemistry showed that the expression rate of CD99 protein was statistically higher in DFSP than in DF paraffin-embedded tissue specimens （73.33% vs. 6.67%, P < 0.05）. As Western blot displayed, the CD99/vinculin ratio was higher in the fresh-frozen DFSP specimen （11.289） than in the two DF specimens （4.743 and 2.402 respectively）. Real-time PCR revealed that the expression intensity of miR-205 was lower in DFSP than in DF fresh-frozen tissue specimens （0.160 vs. 1）. Bioinformatics analysis showed that miR-205 could target the CD99 mRNA 3′-untranslated region. Conclusion Both CD99 and miR-205 may serve as valuable markers for the differential diagnosis between DFSP and DF. 【Key words】 Dermatofibrosarcoma; Fibroma; Antigens, CD99; miR-205

Key words: miR-205