ABSTRACT: MicroRNAs (miRNAs) are non-protein-coding small RNAs in the size range 19–25 nucleotides (nt) that are cleaved from 70-100 nt hairpin pre-miRNA precursors.MiRNAs bind to complementary sequences in the 3′-untranslated regions of their target mRNAs and induce mRNA degradation or translational repression. Recent intensive studies have revealed that miRNAs play important roles in a large number of biological processes, including cellular differentiation, proliferation and death. These wide-ranging biological roles suggest that miRNAs may be involved in cancer development. MiRNAs regulate a variety of biological processes, including developmental timing, signal transduction, cell growth, and cell death.Kaposi’s sarcoma (KS) is a multicentric angioproliferative tumor of mesenchymal origin.8, 9 In 1872, the disease was first described by Moritz Kaposi, and it mostly affects elderly men of Italian, Jewish, or Mediterranean origin. In China, more than 90% of KS cases occur in Xinjiang,12-14 which is a multiethnic gathering place where Uyghur (45.7%) and Han (39.7%) are the main ethnic groups; other groups include the Kazakh (7%) and Hui(4.5%). The specific geographical environment and ethnic specificity may characterize some of the specific features of KS in this area, which might also be reflected in the miRNA expression profile in KS tissues. MicroRNAs (miRNAs) are non-protein-coding small RNAs in the size range 19–25 nucleotides (nt) that are cleaved from 70-100 nt hairpin pre-miRNA precursors.MiRNAs bind to complementary sequences in the 3′-untranslated regions of their target mRNAs and induce mRNA degradation or translational repression. Recent intensive studies have revealed that miRNAs play important roles in a large number of biological processes, including cellular differentiation, proliferation and death. These wide-ranging biological roles suggest that miRNAs may be involved in cancer development. MiRNAs regulate a variety of biological processes, including developmental timing, signal transduction, cell growth, and cell death.Kaposi’s sarcoma (KS) is a multicentric angioproliferative tumor of mesenchymal origin.8, 9 In 1872, the disease was first described by Moritz Kaposi, and it mostly affects elderly men of Italian, Jewish, or Mediterranean origin. In China, more than 90% of KS cases occur in Xinjiang,12-14 which is a multiethnic gathering place where Uyghur (45.7%) and Han (39.7%) are the main ethnic groups; other groups include the Kazakh (7%) and Hui(4.5%). The specific geographical environment and ethnic specificity may characterize some of the specific features of KS in this area, which might also be reflected in the miRNA expression profile in KS tissues.