Aberrant expression of PHLPP1 and PHLPP2 correlates with poor prognosis in patients with hypopharyngeal squamous cell carcinoma.

The PHLPP (pleckstrin homology [PH] domain leucine rich repeat protein phosphatase) family, which represents a family of novel Ser/Thr protein phosphatases, is composed of 2 members: PHLPP1 and PHLPP2. PHLPPs partake in diverse cellular activities to exhibit their antitumor and metastasis suppressor functions. It is necessary to investigate the expression patterns of PHLPP1 and PHLPP2 in hypopharyngeal squamous cell carcinomas (HSCCs) and clarify their clinical significance. A total of 138 patients with primary HSCC who underwent curative surgical treatment as an initial treatment were enrolled in this study. A total of 138 HSCC specimens and 64 adjacent noncancerous mucosal epithelial tissues were collected. The expression levels of PHLPP1 and PHLPP2 were examined by quantitative reverse transcription polymerase chain reaction and immunohistochemistry assays. Correlations between clinicopathological parameters of the patients were further evaluated. PHLPP1 and PHLPP2 mRNA transcript levels were significantly lower in tumor samples than in paired adjacent nontumor mucosae (P