BTK and prostate cancer: In view of the broad-spectrum anti-cancer activity exerted by BTKi in various non-clinical cancer models, BTK inhibition with ibrutinib and acalabrutinib has been evaluated in several proof-of-concept solid tumor trials (e.g., NCT02403271, NCT03525925, NCT03379428, NCT02599824, and NCT02562898) aimed at assessing its potential clinical benefit in patients with solid tumors, including ovarian cancer, breast cancer, lung cancer, prostate cancer, and pancreas cancer (Massó-Vallés et al., 2016; Hong et al., 2019; Overman et al., 2020).