PRKCD and neoplasm: Levels of PKCδ mRNA, however, were significantly higher in ER-positive tumours compared with ER-negative tumours (Mann–Whitney U-test: P=0.007, n=202; Figure 3A) and in patients older than 50 years at diagnosis than in those younger than 50 years (Mann–Whitney U-test: P=0.029, n=208; Figure 3B).