Consistent with the aforementioned finding of Notch signaling overactivation in NSCLC, our data showed that RFC4 expression was significantly upregulated in 81 out of 105 NSCLC tumor tissues as compared to their corresponding adjacent non-cancerous lung tissues in the TCGA lung cancer datasets (fold change >2), as well as in 8 pairs of freshly resected NSCLC tissue specimens (Supplementary Fig. 3a–d). Here, RFC4 is linked to lung cancer.