The average number of PCNA-positive cells for A375P-CXCR1 (1.6-fold; P<0.05) and A375P-CXCR2 (1.8-fold; P<0.05) were significantly higher as compared to A375P-control tumours (Figure 3B, upper panel; Supplementary Figure 2A). This evidence concerns the gene PCNA and neoplasm.