Collagen IV / endomucin double-immunostaining of day 14–21 tumours (when the rate of tumour growth in PdgfrβCre + ;FAKY861F/Y861F mice slows down) from PdgfrβCre + ;FAKWT/WT, PdgfrβCre + ;FAKY397F/Y397F and PdgfrβCre + ;FAKY861F/Y861F mice showed a significant increase in endomucin-negative / collagen IV-positive blood vessel sleeves in tumours from PdgfrβCre + ;FAKY861F/Y861F compared with tumours from PdgfrβCre + ;FAKWT/WT, PdgfrβCre + ;FAKY397F/Y397F mice (Fig. 2c). This evidence concerns the gene EMCN and neoplasm.