We then used a quick in vitro function screening approach to examine whether these 14 genes have effects on malignant phenotypes of SCC cell lines, KYSE30 (ESCC), DaFu (HNSCC) and NCI-H520 (LUSCC) and found that knockdown of EGFR, BRD9 or PPFIA1 expression by short interfering RNA (siRNA) resulted in significant inhibition of cell proliferation (Fig. 3c and Supplementary Figs 18–20). This evidence concerns the gene PPFIA1 and esophageal squamous cell carcinoma.