The biological relevance of laminin 5gamma2 expression at the invading edge of colonic carcinomas.

Previous studies have shown the presence of dilated neoplastic glands with cellular gaps called glandular pores (GPs) and laminin 5gamma2 expression at the invading edge of colonic carcinomas. We now extended our studies to explore a possible association between GP formation and laminin 5gamma2 expression at the invading edge of colonic carcinomas. Immunostain was performed on sections of five consecutive neoplastic glands with and without GPs from 86 colonic adenocarcinomas to assess the expression of laminin 5gamma2. Neoplastic glands with GPs were observed in 85% (73/86) of the tumors. Laminin 5gamma2 was expressed in 92% (335/365) of the neoplastic glands with GPs but only in 17% (63/365) of the neoplastic glands without GPs (p<0.05). Laminin 5gamma2 was overexpressed in the cells at the free ends of the pores in 88% of the neoplastic glands with GPs, but only in 14% of those without pores (p<0.05). Hence, at the growing edge of colonic carcinomas, laminin 5gamma2 was frequently expressed in neoplastic glands having GPs. Remarkably, the tumor cells at the free ends of the GPs overexpressed laminin 5gamma2, indicating increased production of this adhesion-migration macromolecule. The results suggest a close interaction between this adhesion-migration macromolecule, PG formation and the local progression of colonic carcinomas.