HIGH PREVALENCE OF P53 PROTEIN OVEREXPRESSION IN PATIENTS WITH ESOPHAGEAL CANCER IN LINXIAN, CHINA AND ITS RELATIONSHIP TO PROGRESSION AND PROGNOSIS

Background. Linxian is the highest endemic area of esophageal squamous cell carcinoma (ESCC) in China and one of the highest incidence areas in the world. The relationship of p53 protein accumulation to geograp hic variation, pathologic findings, and prognosis has not been investi gated extensively. Methods. Formalin fixed, paraffin embedded ESCC tis sues from 100 patients who underwent esophagectomy between 1973 and 19 83 were immunostained by using monoclonal antibody pAB1801. Results. p 53 overexpression was observed in 41 (87.2%) of 47 tumors of patients in Linxian and in 16 (64%) of 25 additional patients outside Linxian. Its prevalence in the noncancerous epithelium (11/72, 15.3%) and carci noma in situ (1/7, 14.3%) was lower than that in invasive lesions (64/ 93, 68.8%). Its immunostaining intensity increased with the depth of c ancer invasion. Of 30 primary carcinomas with lymph node metastasis, 2 9 (96.7%) were positive. However, only 36 (51.4%) of 70 primary lesion s without metastasis were positive, and a higher intensity was noticed in the metastases. There was a lower expression rate in tumors of pat ients surviving more than 10 years (25/52, 48.1%) than in those surviv ing less than 3 years (40/48, 83.3%). Overall and nonadvanced or metas tasis-free cumulative survival rates were both significantly different in patients with and without p53 protein overexpression. Conclusions. There is a higher expression rate of p53 protein in ESCC in tumors of patients from Linxian than in those from the surrounding area. The ac cumulation of p53 protein is related to the invasiveness and capabilit y for metastases of cancer cells and appears to be a useful prognostic factor for patients with ESCC.