TP63 and cancer: The isoform expression was in tissue regions that did not stain with epithelial cell markers p63 and high molecular weight cytokeratin (HMWCK), which was predominantly in the non-malignant epithelial tissue adjacent to the cancer (NA) (Fig. 3a, right hand panels; Supplementary Fig. S3), demonstrating that Δ133TP53 is expressed in malignant cells (Fig. 3a).