The PIWI protein acts as a predictive marker for human gastric cancer

To investigate the expression of the human PIWI subfamily proteins in gastric cancer and their potential roles in the occurrence, development and prognosis of gastric cancer.

Expression of the PIWI proteins were assessed by immunohistochemistry (IHC) in tissue microarrays (TMA), containing paired tumor tissue and adjacent non-cancer tissue from 182 patients who had undergone surgery in hospital for histologically proven gastric cancer (GC). Prognostic value and correlation with other clinicopathologic factors were evaluated in two classifications.

The expression of PIWIL1-4 was significantly higher in tumor tissue than that in adjacent tissue; A significant correlation was observed between the higher expression of PIWI protein with the T stage, lymph node metastasis and clinical TNM (cTNM); Survival analysis by Kaplan-Meier survival curve and log-rank test demonstrated that elevated PIWIL1 and PIWIL2 expression in cancer tissue predicted poorer overall survival (OS) compared with group in lower expression (36.5% VS 67.6%; 37.4% VS 54.2%; respectively). Notably, multivariate analyses by Cox's proportional hazard model revealed that expression of PIWIL1 was an independent prognostic factor in gastric cancer.

The PIWI subfamily protein is an absolutely key molecular factor along with the tumor occurrence and development. And the PIWI protein could act as a potential biomarker for prognosis evaluation of gastric cancer.