TP63 and squamous cell carcinoma: p40 expression analysis in normal mucosa was found positive in 3 out of 32 specimens (9.37%) with mild nuclear immunostaining as represented in Figure 1A. However, immune-histochemical analysis of oral squamous cell carcinoma tissue specimens revealed that 39 (84.78%) out of 46 stained positives for p40 (Table 3).