Prognostic significance of pS2 protein expression in pulmonary adenocarcinoma

In the present study, pS2 protein expression in pulmonary adenocarcinoma was investigated on paraffin-embedded sections obtained from 170 patients. 28 (16%) patients showed varying degrees of pS2 protein expression in the cytoplasm of tumour cells, as detected by immunohistochemical staining with anti-pS2 protein antibody. There was a significant association between pS2 protein expression and larger tumour size, and the acinar or bronchiolo-alveolar subtype. However, no significant correlations between pS2 protein status and the other clinicopathological factors, i.e. T-factor, N-factor, stage and histological differentiation, were shown. In contrast to breast cancer, patients with pS2-positive pulmonary adenocarcinomas had a significantly worse prognosis than those with pS2-negative pulmonary adenocarcinomas; this was true for stage I patients, as well as for all patients. Multivariate analysis showed that pS2 protein expression was a discriminating variable in overall survival. These findings suggest that pS2 protein status is a possible prognostic indicator in pulmonary adenocarcinoma.