Evaluation of Argonaute protein as a predictive marker for human clear cell renal cell carcinoma

Argonaute subfamily proteins are involved in human organ growth and development. Recent studies found its association with human breast cancer, however, its expression profile and its prognostic value in clear cell renal cancer (ccRCC) have not been investigated. Methods: Expression of the Argonaute proteins were assessed by immunohistochemistry (IHC) in tissue microarrays (TMA), containing paired tumor tissue and adjacent non-cancer tissue from 176 patients who had undergone surgery in hospital for histologically proven ccRCC. Prognostic value and correlation with other clinico-pathologic factors were evaluated in two classifications. Results: Data showed a significant higher expression of Argonaute 1 and Argonaute 2 present in neoplastic tissues compared with that in adjacent tissue; A significant correlation existed between the higher expression of Argonaute 1 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 Argonaute 1 and Argonaute 2 expression in cancer tissue predicted poorer overall survival (OS) compared with group in lower expression (36.3% VS 67.1%; 37.3% VS 53.9%; respectively). Notably, multivariate analyses by Cox's proportional hazard model revealed that expression of Argonaute 2 was an independent prognostic factor in renal cancer. Conclusions: In summary, our present study clarify that the aberrant expression of Argonaute in human RCC is possibly involved with tumorigenesis and development, and the Argonaute protein could act as a potential biomarker for prognosis assessment of renal cancer. Related mechanism is worthy of further investigation.