Correlation between p53 Immunohistochemical Expression, DNA Ploidy and Ki-67 Expression in Gastric Carcinoma

Oh, Young Lyun; Han, Joung Ho; Ko, Young Hyeh; Park, Cheol Keun; Ree, Hwoe J

Abstract

We examined the p53 protein overexpression and evaluated its correlation with pathobiological variables, including: (1) patient age, sex, tumor size, histological type and grade, invasion depth, vascular invasion, perineural invasion and lymph node status; (2) the Ki-67 labeling index in 100 gastric carcinomas; and (3) the DNA ploidy pattern, S phase fraction (SPF), and the proliferation index (PI) in 84 cases using flow cytometry. The positive rate of p53 staining was 48% and the p53 immunoreactivity was independent of variable clinicopathologic factors. No correlation was made between the Ki-67 labeling index with p53 immunostaining and DNA ploidy parameters. Aneuploidy rate was slightly higher in the p53 positive group (55.6%) than the p53 negative group (44.4%)(p=0.097). The mean values of SPF and PI were significantly higher in the p53 protein positive group. Aneuploidy was more often observed in the intestinal type (p=0.038), advanced gastric carcinoma (p=0.015) and lymph node positive group(p=0.039). The above results suggest that although the p53 protein overexpression has no significant correlation with pathological factors and the Ki-67 labeling index, it may play an important role in tumor cell proliferation. Since p53 protein overexpression was slightly higher in the aneuploidy group showing significant correlation with poor prognostic parameters, it is thought that re-evaluation of the p53 mutation by molecular biological study is needed.