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 metastatic and invasive behaviour in carcinomas. The expression of CD44 in 99 transitional cell carcinoma of the urinary bladder was examined by immunohistochemistry using the monoclonal mouse anti-human phagocytic glycoprotein-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 basal portion, while the adjacent of tumor urothelium showed absence or low CD44 expression. In 86.8 % of tumors, the cancer cell stained positively for CD44 antibody. Expression of CD44 was found in well-to moderately differentiated, in superficial tumors but was absence or down-regulated in poorly differentiated and infiltrating tumors. Invasive tumors 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 was no statistically significance difference in the CD44 expression between the primary and recurrence tumors (16 cases) as well as between the recurrence and the no recurrence group. There was no relationship between the CD44 expression and the two proliferating indices. These finding 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.