Finally, 18 common critical proteins, i.e. AKT1, BCL2L1, CCND1, CDH1, CDKN2A, CTNNB1, EGF, EGFR, ERBB2, HRAS, IL6, JUN, KRAS, NOTCH1, SNAI1, STAT3, TNF, and TP53, remained as the core proteins of the three types of cancers. This evidence concerns the gene IL6 and cancer.