Apoptosis, cell proliferation and expression of oncogenes in gastric carcinomas induced by preoperative administration of 5-fluorouracil

The purpose of this study was to examine the correlations among enhancement of apoptosis, cell proliferation and expression of oncogenes in gastric carcinomas induced by preoperative oral administration of 5-fluorouracil (5-FU). The occurrence of spontaneous apoptotic cell death in 42 patients with gastric carcinoma was analyzed in the biopsy specimens preoperatively. p53 status was examined by polymerase chain reaction-single strand confirmation polymorphism and sequencing. Fourteen patients received oral administration of 5-FU at 300 mg/body/day for 7 days preoperatively. For detection of apoptotic cells, apoptotic incidences (AIs) were examined by the terminal deoxynucleotidyl transferase-mediated deoxy-uridine triphosphate biotin nick end labeling method, on gastric carcinoma lesions based on the endoscopic findings before administration in the biopsy and resected tissues. Expressions of p53, Bcl-2, Bax gene and proliferating cell nuclear antigen (PCNA) were also examined by immunohistochemical staining. On preoperative biopsy, p53 point mutation was observed in 14 of the 42 tumors. The immunohistochemical staining status and point mutation of p53 gene (positive or negative) were identical in 32 of the 42 tumors (76.2%). The average AIs of the biopsy specimens were 1.58+1.26% on p53-negative staining (n=19) and 1.14+/-1.02% on p53-positive staining (n=23), a significant association was not recognized between p53 expression and AI. In the preoperative administration group, the PCNA labeling index was significantly higher in the biopsy specimens than in the resected tissues (43.6+/-12.8% vs. 35.3+/-8.8%, p<0.01). In addition, postoperatively, the rate of AI was significantly more accelerated in p53-negative staining (n=6) than in p53-positive staining (n=8) (0.89+/-0.65% --> 4.18+/-3.26%, p<0.05 vs. 1.20+/-0.60% --> 2.60+/-2.60%, NS). There was no significant correlation between AI and Bcl-2 or Pax staining. Immunohistochemical analysis of p53 and PCNA stainings in biopsy specimens appears to be a well-characterized indicator of sensitivity of chemotherapy in gastric carcinomas.