Characterization of Opa interacting protein 5 as a new biomarker and therapeutic target for oral cancer

Oral cancer is a leading cause of cancer-related death worldwide. Current treatment for oral cancer includes surgery, radiotherapy, and chemotherapy; however, their effectiveness is still limited. To identify a new prognostic biomarker and therapeutic target for oral cancer, the Opa interacting protein 5 (OIP5), which plays an essential role in the proper segregation of chromosomes, was examined. Immunohistochemical staining using tissue microarrays indicated that OIP5 was expressed in 120 of 164 (73.2%) oral cancers but was minimally expressed in normal oral tissues. OIP5 expression was significantly associated with poor prognosis in patients with oral cancer. Overexpression of OIP5 enhanced the growth of oral cancer cells, whereas OIP5 knockdown using small interfering RNAs (siRNAs) significantly inhibited cell growth through cell cycle arrest at the G2/M phase. Suppression of OIP5 expression also induced senescence of oral cancer cells. Overall, the findings of the present study suggest that OIP5 may be a candidate prognostic biomarker and therapeutic target in oral cancer.