VHL and breast cancer: In line with this, ectopic Notch1 ICD expression, which results in high levels of Notch signaling activation, increased normoxic HIF2α protein in primary breast cancer cells (Fig. 3a), human medulloblastoma cell lines D324 and DAOY (Fig. 3b, c), as well as the VHL-deficient 786-O renal carcinoma cell line (Fig. 3d).