EXPRESSION OF THE CELL-ADHESION MOLECULE CD44 IN TRANSITIONAL-CELL CARCINOMA OF THE URINARY-BLADDER

CD44, an integral membrane glycoprotein has diverse functions in cell- cell and cell-matrix interactions and may be a determinant of metastat ic and invasive behaviour in carcinomas. The expression of CD44 in 99 transitional cell carcinoma of the urinary bladder was examined by imm unohistochemistry using the monoclonal mouse anti-human phagocytic gly coprotein-l, CD44 (clone DF 1485) on formalin-fixed, paraffin-embedded tissue. In 18 tumor the adjacent mucosa was also examined. Normal and distant of tumor urothelium showed strongly CD44 staining in the basa l portion, while the adjacent of tumor urothelium showed absence or lo w CD44 expression. In 86.8 % of tumors, the cancer cell stained positi vely for CD44 antibody. Expression of CD44 was found in well-to modera tely differentiated, in superficial tumors but was absence or down-reg ulated in poorly differentiated and infiltrating tumors. Invasive tumo rs showed a more uniform staining pattern (positive or negative in the most areas) and in more cases there was lost of the CD44 expression. Cases with squamous metaplasia showed higher CD44 expression. There wa s no statistically significance difference in the CD44 expression betw een the primary and recurrence tumors (16 cases) as well as between th e recurrence and the no recurrence group. There was no relationship be tween the CD44 expression and the two proliferating indices. These fin ding shows that in transitional cell carcinoma of the urinary bladder, absence or low CD44 expression correlates with infiltrating and more aggressive tumors and this expression is independent of proliferative activity of the tumor.