Type IV collagen immunoreactivity in colorectal cancer. Prognostic value of basement membrane deposition.

Using antibodies to type IV collagen, basement membrane (BM) deposition at the tumor-stromal border was studied in 163 cases of colorectal carcinomas. Immunoreactivity was scored semiquantitatively as moderate/extensive versus limited BM deposition and correlated with Dukes' stages and survival data. Cases with limited BM deposition showed an overall significant shorter survival and were overrepresented in Dukes' Stages C/D. Stratification of the cases, for limited versus moderate/extensive BM deposition and Dukes' Stages A/B and C/D, showed that in Dukes' Stages C/D, cases with moderate/extensive BM deposition reached a plateau phase in the survival curve after 2 years. Cases with limited BM deposition showed a continuous downward course on the survival curve. The results suggest that immunostaining of BM in cases in Dukes' C differentiates tumors with relatively high invasive and metastatic capacity from tumors with low invasive and metastatic capacity.