Expression of G α12 predicts progression and prognosis of oral squamous cell carcinomas in T aiwan

Background Expression of Gα12 is found to be associated with cancer cell proliferation, migration, invasion, and metastasis. Methods This study used immunohistochemistry to examine the expression of G α12 protein in 100 specimens of oral squamous cell carcinoma ( OSCC ), 45 specimens of oral epithelial dysplasia ( OED ), and 36 specimens of normal oral mucosa ( NOM ). Results The mean G α12 labeling indices ( LI s, defined as the percentage of positive cells in total cells) increased significantly from NOM (7 ± 11%) through OED (21 ± 20%) to OSCC samples (53 ± 33%, P  < 0.001). The higher mean G α12 LI was significantly associated with OSCC s with larger tumor size ( P  =   0.003), positive lymph node metastasis ( P  =   0.002), or more advanced clinical stages ( P  =   0.003). Positive lymph node metastasis ( P  =   0.039) and Gα12 LI  > 50% ( P  =   0.009) were identified as independent unfavorable prognosis factors by multivariate analyses with Cox regression model. Moreover, Kaplan–Meier curve showed that OSCC patients with a G α12 LI  > 50% had a significantly poorer cumulative survival than those with a Gα12 LI  ≤ 50% (log‐rank test, P  =   0.009). Conclusions Our results showed a stepwise and significant elevation in G α12 protein expression from NOM through OED to OSCC s, suggesting that overexpression of G α12 protein may be an early event in oral carcinogenesis and may play a pivotal role in oral cancer development. Moreover, the G α12 protein can be a biomarker for prediction of the progression of OSCC s and the prognosis of patients with OSCC in T aiwan.