RFC4 and non-small cell lung carcinoma: Our study suggests that both the transcriptional upregulation of RFC4 by activated Notch1 signaling and RFC4 amplification should contribute to high levels of RFC4 to varying degrees in LUAD and LUSC, both of which could utilize the pivotal roles of the positive feedback loop between RFC4 and NICD1 in coupling NSCLC metastasis and stemness properties.