PTGS2 and Kaposi's sarcoma: The positivity of spindle-shaped KS tumor cells for CD105 and COX-2, first reported in our study, in correlation with CD34, VEGF, SMA, and c-KIT positivity [3], [7], [41], seems to suggest that KS, similar to other fibroblastic tumors, originates from the PMCs and is related to the VEGF secretion.