On the other hand, off-target inhibition of EGFR allows ibrutinib to directly suppress the proliferation, growth and stemness of certain types of solid tumors that are dependent on EGFR oncogenic pathways, including pancreatic cancer, hepatocellular carcinoma (HCC) and esophageal squamous cell carcinoma (ESCC) (97–99). The gene discussed is EGFR; the disease is esophageal squamous cell carcinoma.