TGFB1 and cancer: Although pericyte coverage was unchanged between the control and the TβRIIiΔEC mice in both tumor-bearing cohorts, abundant red blood cells were found within the cancer tissues of TβRIIiΔEC mice, having leaked from podocalyxin-positive tumor blood vessels, indicating vessel fragility (Figure 2I) corroborating the proposition that TGF-β promotes blood vessel maturation.19