This group is characterised by low expression levels of CD31 in non-tumour stroma (LI < 6%) and low ratios of tumour to non-tumour stromal PR expression levels (LI ratio < 80%), meaning that stromal PR expression is lower in PCa compared to PNT samples from the same patient (Figs 4 and 5). The gene discussed is PECAM1; the disease is neoplasm.