Evaluation of INHBB expression in primary OSCCs. Representative IHC results of activin B in normal oral tissues (A) and primary OSCCs (B). Original magnification, ×200. Scale bars, 50 μm. (C) The status of activin B protein expression in primary OSCCs (n=103) and normal counterparts. Activin B IHC scores for normal oral tissues and OSCCs range from 26.0 to 80.0 (median, 55.1) and 71.0 to 209.0 (median, 126.1), respectively. Activin B protein expression levels in OSCCs are significantly higher than in normal oral tissues (*P < 0.05, Student's t-test). (D) The area under the curve (AUC) of the ROC curve analysis is 0.71, and the cutoff value is 101.3 for the regional lymph node metastasis (P < 0.05).