In another study, heregulin as a growth factor, binds to ErbB3 and ErbB4 transmembrane receptor tyrosine kinases and upregulates the expression of anti-apoptotic, invasive, and metastatic genes in BC cells via autocrine activation of NF-κB, which causes the drug-resistant phenotype of these cells [109]. The gene discussed is NFKB1; the disease is breast cancer.