Immunohistochemical Detection of PS2 Protein and Heat Shock Protein-70 in Pancreatic Adenocarcinomas. Relationship with Disease Extent and Patient Survival

We investigated pS2 and HSP-70 protein expression in 36 pancreatic adenocarcinomas for their effect on disease extent and patient outcome. The cases were reviewed, histologically diagnosed, typed, graded, and staged. Lymphatic vessel, blood vessel and perineural invasion as well as lymph node, resection margin and adjacent organ involvements were re-evaluated. The standard streptavidin biotin immunperoxidase method was used for immunostaining with pS2 and HSP-70 antibodies. Cytoplasmic staining with both antibodies was scored semiquantitatively. The scores were compared with histopathological prognostic parameters using statistical methods. Standard prognostic parameters and staining scores were tested by survival analysis in terms of their effect on survival. All the tumors showed a positive cytoplasmic reaction with HSP-70 antibody. Seventy-seven percent of the tumors showed positive cytoplasmic staining with pS2 antibody (22.2% +, 13.9% ++ and 41.7% +++). There was a statistically significant difference between HSP-70 staining scores with N status and final stages of the tumors (Chi-square, p = 0.03 and p = 0.026, respectively), while neither direct nor inverse correlation was detected for both parameters. PS2 staining scores showed no statistically significant relationship with tumor grade T, M status, perineural invasion, lymph and blood vessel invasion. In tumors with extensive staining with pS2, tumor stage tended to be low (Chi square, p = 0.024, Kendall Tau-b, r: –0.336, p = 0.036). There was a statistically significant difference and inverse correlation between tumors with extensive pS2 staining and tumors with less intense staining in terms of lymph node metastasis (Chi-square, p = 0.041, Kendall Tau: p = 0.024, r = –0,373). In the R0 resection group, in univariate analysis, we found that with higher scores of HSP-70 staining, the prognosis of the patient tended to improve. (Cox regression, p = 0.013). In multivariate analysis, HSP-70 expression was found to be an independent prognostic factor. We found no relationship between pS2 staining and patient survival.