Background: CD44 has diverse functions in cell-cell and cell-matrix interactions and its expression appears to be an indicator of invasive and metastatic behaviour in carcinomas. However, contradictory data have been reported about the correlation between CD44 expression and prognosis in colorectal carcinomas. We aimed (i) to establish whether immunohistochemically detectable CD44 expression is related to tumor aggressiveness, (ii) to correlate CD44 expression with the degree of tumor differentiation and (iii) to determine the relationship between CD44 expression and patient survival and other conventional clinicopathological features.
Patients and methods: The immunohistochemical expression of CD44 in a series of 111 colorectal carcinomas was examined using the monoclonal mouse anti-human phagocytic glycoprotein-1, CD44 (clone DF 1485) in correlation with clinicopathological variables. To achieve a reliable semi-quantitative evaluation, not only the staining intensity but also the distribution of positive tumor cells were analyzed.
Results: CD44 staining was high-grade positive in 42 and low-grade positive/negative in 69 tumor tissues. There was no association between CD44 expression and tumor size, histological differentiation, depth of invasion, lymph node involvement, clinical stage of the disease, or the radicality of surgical resection. CD44 expression was not correlated significantly with recurrence and distant metastases. Multivariate analysis showed that only the modified Astler-Coller (MAC) staging system was an independent prognostic factor of recurrence (HR=15.267; 15.267-6.808, 95% CI; p=0.001) and survival (HR=37.064; 13.309-103.220, 95% CI; p=0.001). Kaplan-Meier curves showed that there was no significant association between CD44 expression and recurrence and overall survival in either MAC B or C colorectal cancer.
Conclusion: Expression of CD44 was not associated with any conventional clinicopathological features. CD44 cannot be considered as a prognostic predictor of recurrence, metastasis and overall survival.