Abstract: Zhang Yan*, Li Tingting, Zhang Dezhi, Zou Yunmin, Wu Caoying, Wang Hongjuan, Pu Xiongming. *Shihezi University School of Medicine, Shihezi 832002, Xinjiang, China Corresponding author: Pu Xiongming, Email: puxiongming@126.com 【Abstract】 Objective To analyze the clonality in Kaposi's sarcoma （KS） lesions by evaluating X-chromosome inactivation pattern in the human androgen receptor （HUMARA） gene. Methods Twenty-five paraffin-embedded tissue specimens were collected from female patients with KS （n = 15） or cutaneous hemangioma （n = 10）. DNA was extracted from these specimens, and digested with the methylation-sensitive restriction endonuclease HpaⅡ. PCR was performed to amplify the HUMARA gene, and the amplicons were separated on a 10% denaturing polyacrylamied gel and stained with ethidium bromide（EB）. The loss of heterozygosity of the HUMARA gene was defined as the presence of two DNA fragments before and one fragment after the endonuclease digestion. The clonality in KS lesions was assessed based on the above results. Results Among the 15 patients with KS, 13 （86.7%） were heterozygous for the HUMARA gene, of which, 92.31% （12/13） showed loss of heterozygosity of the HUMARA gene on X-chromosome, suggesting a monoclonal origin. Of the 10 patients with hemangioma, 9 were heterozygous for the HUMARA gene, and only one lost heterozygosity of the HUMARA gene. The heterozygosity rate for HUMARA gene was significantly different between the patients with KS and hemangioma （P < 0.01）. No statistical difference was observed in the clonality status of KS between patients of different nationality, at different stages, or between patients with and without complicated human immunodeficiency virus （HIV） infection （all P > 0.05）. Conclusion KS is monoclonal in origin.

Key words: Sarcoma, Kaposi, X Chromosome inactivation, Androgen receptor gene, Clonality analysis