The significance of CD44 variants expression in colorectal cancer and its regional lymph nodes.

CD44 is a cell adhesion molecule with numerous isoforms created by mRNA alternative splicing. Expression of CD44 variants has been suggested to play a potential role in tumor progression and metastasis. We designed primers CD44V, CD44V6/7, CD44R1 and CD44V6-10 to analyze and compare the roles of each CD44 variants. Expressions of CD44 variants were investigated in normal colonic mucosa, the lymph nodes which was histopathologically free of cancer cell, and cancer tissues of 44 human colorectal cancer patients by RT-PCR method. The expression of CD44V was observed in 28 out of 39 (71.8%) tumors and 7 out of 11 (63.6%) N1 normal regional lymph nodes, and CD44V6/7 was observed in 28 out of 39 (71.8%) tumors and 9 out of 11 (81.8%) N1 normal regional lymph nodes. The expressions of CD44V and CD44V6/7 were most frequently observed compared with any other CD44 variants. In normal colonic mucosa, the expression of CD44 variants are low but in cancer tissue and its regional lymph node, the expression of CD44V and CD44V6/7 were significantly higher and more frequent than any other CD44 variants (p<0.05). These results suggest that CD44V and CD44V6/7 can be a molecular marker for colorectal cancer and its micrometastasis to the regional normal lymph node.