Abstract: Objective To study the expressions of c-Met at differential stages of endemic Kaposi's sarcoma (KS) and AIDS-related KS and its roles in the pathogenesis. Methods Twenty-one cases of endemic KS and 9 cases of AIDS-related KS from Pathological Department, Muhimbili Medical Centre, Tanzania, were analyzed clinicopathologically. Among them, 21 cases were cutaneous KS, and other 9 cases were lymph node KS. The classification was based on the histopathological characteristics of KS. Immunohisto-chemistry and hybridization in situ were performed for the detection of c-Met protein or c-Met mRNA in endemic KS and AIDS-related KS. Resuits KS were classified into three stages, i.e. early stage (angiomatous type, 11 lesions), advanced stage (spindle cell type, 14 lesions), and medial stage (mixed type, 13 lesions) according to the proportion of blood vessel components and spindle cells in the lesions. There was significant difference in the c-Met protein expression on different stages (P<0.01), with similar situation of c-Met mRNA expression. There was no difference in c-Met protein and c-Met mRNA expression between epidemic KS and AIDS-related KS (P>0.05). Conclusion The up-regulated expression of c-Met protein and c-Met mRNA in KS suggests that c-Met may play an important role in the pathogenesis and development of endemic KS and AIDS-related KS.

Key words: Sarcoma, Kaposi, Proto-oncogene proteins c-Met, RNA, messenger