In breast cancer cells, NOTCH3 acts as a positive regulator of ER expression, an effect that is mediated by the binding of NOTCH3 at the level of CSL (CBF1, suppressor of hairless, Lag-2) binding region of the ERalpha gene promoter, with the consequent stimulation of the rate of transcription of this gene [393]. The gene discussed is RBPJ; the disease is breast cancer.