To further ascertain the reliability of this IRGPs signature, we selected six genes (IL13RA2, RORC, IL20, SAA2, FABP6 and CHGB) to conduct qRT-PCR experiments in Het-1A cells and EC cells lines (KYSE-150 and KYSE-450) based on the fold change, p-values between tumor and normal tissues gene expression in public databases, as well as high-frequency repeat among gene pairs (Table S4). The gene discussed is SAA2; the disease is neoplasm.