Our observation of reduced pericyte PDGFRβ levels, signalling and resulting inhibited responses to PDGF-BB in α6-integrin deficient pericytes may explain the tumour blood vessel phenotypes we observe in the pdgfrβcre+;α6fl/fl mice, including reduced pericyte blood vessel investment and increased detachment of pericytes to endothelial cells, since these functions have been reported to be mediated by PDGF-BB (Abramsson et al., 2003; Hellberg et al., 2010). This evidence concerns the gene PDGFRB and neoplasm.