High level of expression of alpha-fetoprotein receptor in gastric cancers

The expression of the receptor for alpha-fetoprotein (AFP-R) was examined immunohistochemically in 47 cancer and 14 benign human gastric tissues. Rabbit polyclonal antibody against human AFP-R was used for immunohistochemical staining. Thirty-four of the 47 cancer tissues expressed AFP-R showing granular or reticular staining on the cancer cell surface, while only 2 of 61 control cases (14 benign gastric tissues and 47 nonmalignant tissues adjacent to cancer) showed faint and homogeneous staining in the cytoplasm of noncancerous cells. There was a significant difference in staining intensity between the cancerous and noncancerous groups. However, no statistically significant difference in staining intensity was found among the groups of well-differentiated, moderately differentiated and poorly differentiated adenocarcinomas. On the other hand, the staining intensity of signet ring cell carcinoma was significantly weaker than that of the three adenocarcinoma groups. The high level of AFP-R expression in gastric cancers may allow the use of AFP-R as a new clinically useful marker of gastric cancer in the tissue level.