RFC4 and squamous cell lung carcinoma: As shown in Fig. 3a; Supplementary Fig. 3e–h, overexpression of RFC4 in LUAD (A549) and lung squamous cell carcinoma (LUSC) (H1703) cell lines induced the expression of invasion- and stemness-promoting genes, potentiated the invasive and self-renewal abilities of these NSCLC cells to invade through the Matrigel and grow into more, larger-sized nonadherent cell spheres, and increased the proportions of SP cell fractions.