The Study on Comparing the Expression of the Collagen IV with different Histopathologic Features of the Colorectal Carcinomas

ABSTRACT

The malignant potential of a tumor is related to its ability to dissociate invasion and seed other sites-metastasis. In either instance, the tumor cells are confronted with a barrier signif icantly composed of type IV collagen. This type IV collagen is a major structural protein of basement membranes. Using immunohistochemical method to detect type IV collagen, intensity of stain and continuity of basement membrane at the tumor-stromal border was studied in surgical specimens from 47 colorectal carcinomas at the Pusan Paik-Hospital. Immunoreactivity was evaluated semi-quantitatively as three categories; Type-1, thick or normal basement membrane with or without minimal discontinuity; Type-2, thin basement membrane with or without moderate discontinuity; Type-3, fragmented or absent basement membrane. Also, in each case the tumor morphologic features were identified. The histologic type, differentiated grade, desmoplastic response, lymphatic and vascular invasion, lymph node involvement, tumor size and modified Dukes' stage were estabilished. Type-1 immunoreactivity was significantly observed in well-differentiated, negative lymph node, Dukes' stage B1/B2 tumors, and Type-3 was in poorly differentiated, positive lymph node, Dukes' stage C2/D. The expres sion of collagen IV in basement membrane was statistically significant correlated with differentiated grade, lymph node metastasis and modified Dukes' stage. By contrast, no statistically significant correlation was found between paucity of type IV collagen and the other parameters. The result suggest that expression of type IV collagen in basement membrane may be a useful prognostic marker, and may play a part in the invasive and metastatic process of colorectal carcinomas.