NOTCH1 and non-small cell lung carcinoma: Interestingly, RFC4 overexpression largely increased, whereas silencing RFC4 decreased NICD1 protein levels without affecting the mRNA levels of Notch1 or the quantities of full-length Notch1 proteins both in various NSCLC cell lines and primary NSCLC cells (Fig. 4a and Supplementary Fig. 6a).