To this end, we conducted the experiments in a fibroblast cell line derived from human mammary fibroblast (HMF) tumor stromal fibroblasts, in which we had previously removed the NOTCH2 gene by CRISPR/Cas9 cells to generate a fibroblast cell line with very low endogenous Notch signaling due to the removal of NOTCH2 (HMFΔN2) (Strell et al., 2019), but with the endogenous NOTCH3 gene retained, thus more closely mimicking the human IMF heterozygous situation. The gene discussed is NOTCH3; the disease is neoplasm.