Overexpression of PREX1 in oral squamous cell carcinoma indicates poor prognosis.

Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger (P-Rex) proteins control many fundamental cellular functions including cell migration, actin cytoskeletal rearrangement and adhesion in many cancers. However, P-Rex1 expression and its prognostic effect and possible clinical value are not clearly elucidated in human oral squamous cell carcinoma (OSCC). Here, OSCC tissue microarrays were used to verify the expression levels of P-Rex1, coinhibitory immune checkpoints and tumor associated macrophage (TAM) markers, and to analyze the relationship between PREX1 expression levels and clinicopathological characteristics in OSCC. The study found that P-Rex1 expression was elevated in OSCC compared to dysplasia and normal mucosa (P < 0.0001). In addition, patients who expressed high PREX1 had a poorer prognosis than those who expressed low PREX1 (P = 0.0070). Furthermore, positive correlations were found between P-Rex1 expression and the immune checkpoints PD-L1, Galectin-9 and B7-H4, and the TAM markers CD68, CD206 and CD163. In short, these findings implicated that overexpression of P-Rex1 may predict a poor prognosis in human OSCC.