HIF1A and neoplasm: It was also observed that the stabilization of both HIF1α and HIF2α in VHLΔ/Δ mice promotes the clear cell phenotype of tumor cells while tumor cells from VHLΔ/ΔHIF1αΔ/Δ mice and VHLΔ/ΔHIF2αΔ/Δ mice had reduced frequency of the clear cell phenotype (Hoefflin et al., 2020).