Abstract: Objective To study the phenotypic characteristics of Kaposi's sarcoma(KS) in different histological types. Methods Phenotypic characteristics of KS in different histological types were studied with morphology, immunohistochemistry, hybridization in situ, and DNA ploidy analysis. Results KS was classified into three types, i.e., angiomatous type (early stage, 11 specimens), spindle cell type (late stage, 14 specimens), and mixed type (mid stage, 13 specimens) according to the proportion of blood vessels and spindle cells in the tumor tissue. CD34 and FⅧRAg expression was significantly different among three types(P<0.01), strong in the angiomatous type, weak in the spindle cell type. The expression of p53 and c-met protein was weak in the angiomatous type, and strong in the spindle cell type(P<0.01). The expression of c-met mRNA in three types was similar to the c-met protein, but the expression of p53 mRNA was stronger in angiomatous type than that in spindle all type. The expression of c-erbB-2 in spindle cell type was stronger than that in angiomatous type (P<0.01). The index of PCNA immunostanining was significantly higher in the spindle cell type than that in the angiomatous type(P<0.01). DNA ploidy analysis showed that almost all KS cells were diploidy. Conclusions Phenotypic characteristics of KS are varied in their different development stages, which implies that angiomatous stage may be a benign lesion, spindle cell stage a malignant lesion, and mixed stage a transition lesion (or borderline lesion).

Key words: Sarcoma, Kaposi, Phenotype, Antigen, CD34, Protein p53, Proto-oncogene protein c-met, Receptor, c-erbB-2