ITK and hepatocellular carcinoma: These side effects are mediated by both on-target inhibition of BTK and variable off-target inhibition of other kinases such as interleukin-2-inducible T-cell kinase (ITK), tyrosine kinase expressed in hepatocellular carcinoma (TEC), CSK, SRC, BMX, JAK3, epidermal growth factor receptor (EGFR), c-Kit and platelet-derived growth factor receptor (PDGFR), etc. (Bitar et al., 2018; Liclican et al., 2020; Lipsky and Lamanna, 2020; Sibaud et al., 2020; Estupinan et al., 2021).