Prognostic significance of cytosolic pS2 protein content in gastric cancer.

pS2, a 60-amino-acid chain peptide which is the most widespread estrogen-induced RNA messenger in MCF-7 breast cancer cells, is normally detected in the epithelium of gastric mucosa. The aims of this work were to evaluate the cytosolic pS2 content and its clinical significance in gastric carcinomas. Cytosolic pS2 levels were examined by immunoradiometric methods in 108 patients with primary gastric adenocarcinomas. The mean follow-up period was 23.3 months. The cytosolic pS2 levels of the tumors ranged widely, i.e., from 0.1 to 3217 ng/mg protein. There were no significant differences in pS2 content between tumors (mean ± standard error: 137.2±31.4 ng/mg protein) and paired adjacent mucosa samples (n=84; mean ± standard error: 249.6±32.6 ng/mg protein), nor were there any significant differences in tumoral pS2 levels with respect to clinicopathologic parameters such as patient age and sex or tumor location, stage, histologic type or grade. However, the results indicated that high intratumoral pS2 levels were significantly and independently associated with an unfavorable outcome in the overall group of patients (p=0.0266) and in patients with resectable gastric cancer (p=0.003). In conclusion, pS2 may represent a useful biological marker in gastric cancer.