The relationship between the expression of blood group-related antigens and the cell proliferation of pancreatic carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters.

The relationship between expression of blood group-related antigens (BGRAs) A, B, H, and cell proliferation was investigated during pancreatic carcinogenesis and in transplanted pancreatic carcinomas induced by N-nitrosobis(2-oxopropyl)amine in hamsters. Immunohistochemical staining was performed using monoclonal antibodies (MoAbs) against BGRAs A, B, H, and bromodeoxyuridine (BrdU). The labeling index (LI) was determined as the ratio of the number of BrdU-labeled cells to the total number of cells counted in each lesion. During carcinogenesis, the LI was observed to increase in line with the increase in the extent of atypism (P < 0.01). The mean LIs of the hyperplasia, atypical hyperplasia, and carcinoma were 0.32, 3.21, and 10.2, respectively. The mean LIs of transplanted carcinomas were higher than those of the original carcinomas (P < 0.01). The reactivity with each of the antibodies was determined using an arbitrary scoring system. Staining with MoAbs A and B (staining intensity; 1+ to 3+) appeared to be more intense than that with MoAb H (1+ to 2+) during carcinogenesis. Regarding the growth rate, which was very high, in the transplanted carcinomas, MoAb A reacted with all the cancer cells (4+), whereas, MoAbs B and H reacted with fewer cells (1+ to 3+). These results indicate that the A antigen in particular is associated with the cell proliferation of pancreas, especially with carcinoma induced in hamsters.