Glycoprotein CD44 expression in colorectal neoplasms - An immuno-histochemical study including correlation with cathepsin D, extracellular matrix components, p53, Rb, bcl-2, c-erbB-2, EGFR and proliferation indices

CD44 has diverse functions in cell-cell and cell-matrix interactions and ma y be a determinant of metastatic and invasive behaviour in carcinomas. The immunohistochemical expression of CD44 in a series of 110 colorectal carcin omas and 25 adenomas was examined using the monoclonal mouse anti-human pha gocytic glycoprotein-l, CD44 (clone DF 1485) in correlation with the expres sion of basement membrane (BM) antigens (type IV collagen, laminin), fibron ectin, cathepsin D, p53, Rb, bcl-2, c-erbB-2, EGFR, proliferation indices ( Ki-67, PCNA) and with other conventional clinicopathological variables. In adenomas, low CD44 expression (<10% of neoplastic cells) was present in 16% , moderate (10-50% of neoplastic cells) in 52% and extensive (>50% of neopl astic cells) in 32% of cases. In carcinomas, low CD44 expression was found in 14.5%, moderate in 28.2% and extensive in 57.30%. Although the CD44 expr ession was higher in carcinomas than in adenomas, we found no statistically significant difference between these two groups. CD44 expression in carcin omas was positively correlated with tumour size (P=0.018), tumour cells cat hepsin D (P=0.022), stromal cell cathepsin D (P=0.003) and Rb protein (P=0. 021). An inverse correlation was observed between CD44 and the anti-apoptot ic protein expression bcl-2 in adenocarcinomas (P=0.039) and in adenomas (P =0.021). These data suggest that CD44 may be involved in the process of inv asion and metastasis, probably with the cooperation of cathepsin D. Its exp ression may be an indicator of poor prognosis in colorectal adenocarcinomas .