Proliferative activity of gastric cancer assessed by immunostaining for proliferating cell nuclear antigen

The growth activity of 107 gastric carcinomas was assessed by immunohistochemical staining for formalin-fixed, paraffin-embedded tissue with a monoclonal antibody against proliferating cell nuclear antigen (PCNA). When the tumor doubling times (Tds) of 10 patients were estimated from the serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9, there was an inverse correlation between the Tds and PCNA labeling index (LI) at P = 0.055. Flow-cytometric analysis was carried out by double staining for PCNA and DNA using fresh materials from 14 patients. The PCNA-positive cell fraction revealed by flow cytometry showed a good linear correlation with PCNA LI in routinely stained tissue. The LI of well-differentiated adenocarcinoma was significantly higher than that of the poorly differentiated type. When the LI was analyzed in well- or poorly differentiated adenocarcinoma, the value was significantly higher in the well-differentiated type with hepatic metastasis and in the poorly differentiated type with lymph node metastasis.