Laminin 5 beta3 and gamma2 chains are frequently coexpressed in cancer cells.

Laminin 5 plays an important role in cell migration during tumor invasion and tissue remodeling. However, previous studies have not clarified whether laminin 5 beta3 chain is coexpressed with laminin 5 gamma 2 chain in cancer cells. The present immunohistochemical study investigated the distribution of the laminin 5 beta3 and gamma2 chains in 20 cases of squamous cell carcinoma of the tongue and 17 cases of colorectal carcinoma. Laminin 5 beta3 and gamma2 chains were expressed in the cytoplasm of tumor cells. Tumor cells at the cancer-stromal interface and at the invasive front frequently showed immunopositivity for laminin 5 beta3 and gamma2 chains in both squamous cell carcinoma of the tongue and colorectal carcinoma. Furthermore, strong expressions of these two proteins were observed in cancer cells invading in a scattered manner. Laminin 5 beta3 expression correlated significantly with laminin 5 gamma2 expression in 20 cases of squamous cell carcinoma of the tongue (P = 0.0002) and 17 cases of colorectal carcinoma (P < 0.0001). These results suggest that in squamous cell carcinoma of the tongue and colorectal carcinoma, laminin 5 gamma2 chain and beta3 chain are both important in the invasiveness of cancer cells.