Protein tyrosine phosphatase receptor R and Z1 expression as independent prognostic indicators in oral squamous cell carcinoma.

The actions of tyrosine phosphorylation and dephosphorylation are controlled by tyrosine kinases and phosphatases. Although substantial previous data have revealed the role of several protein tyrosine phosphatases (PTPs) in various cancers, the function of protein tyrosine phosphatase receptor R (PTPRR) and protein tyrosine phosphatase, receptor-type, Z polypeptide 1 (PTPRZ1) proteins in oral cavity squamous cell carcinoma (SCC) has not been studied to date. The PTPRR and PTPRZ1 immunoreactivity in 67 formalin-fixed and paraffin-embedded oral cancer tissues at different stages were analyzed with the technique of immunohistochemistry (IHC). The presence of PTPRR in cancerous tissue was confirmed by Western blotting. The occurrence of PTPRR and PTPRZ1 proteins in the cancer specimens was more frequent in lower grade tumors. In addition, the association between the immunoreactivity of both examined proteins and improved patients survival was detected. Moreover, the PTPRR expression was found to be related to the absence of synchronous lymph node involvement. The above results indicate that the PTPRR and PTPRZ1 protein expression should be monitored in oral cancer for patients' prognostic stratification.