Intense p63 staining was observed in significantly smaller number of primary tumour samples in high-grade (8 out of 41) or muscle-invasive carcinomas (3 out of 23) than in low-grade (15 out of 20, P<0.0001) or Ta–T1 tumours (18 out of 32, P<0.01), respectively. This evidence concerns the gene TP63 and neoplasm.