摘要Background Oral squamous cell carcinoma (OSCC) is one of the most common malignancies in the oral and maxillofaoial region.Yes-associated protein 1 (YAP1) has been implicated as a bona fide oncogene in solid tumors.We seek to elucidate the role of YAP1 in OSCC tissue.Methods We identified YAP1 gene and protein overexpression in 30 OSCC patients and 10 normal oral mucosa tissues by immunohistochemistry,Western blotting and reverse transcription polymerase chain reaction (RT-PCR).Results In the normal oral mucosa by immunohistochemical staining,YAP1 mainly located in both the cytoplasm and nucleus mainly the nuclei of the basal cells.In OSCC,the expression of YAP1 translocated from the nucleus to cytoplasm;YAP1 being mainly located in both the cytoplasm and nucleus of the adjacent mucosa.The expression of YAP1 gradual increased in normal oral mucosa,tumor adjacent mucosa and low grade,middle grade,high grade OSCC tissue by Western blotting.Significant difference was found between the expressions of the normal oral mucosa and OSCC tissue (P ＜0.05).The coincidence was detected between the normal oral mucosa and OSCC tissue by RT-PCR (P ＜0.05).Conclusions YAP1 is involved in the carcinogenesis and development of OSCC.There is a transformation between nucleus and cytoplasm.