The fact that one pyrazolo[3,4-d]pyrimidine, the BTK inhibitor ibrutinib (7th best-selling cancer drug of 2018), has been approved to treat B-cell cancers and several more inhibitors targeting different kinases are in advanced clinical trials, demonstrate both the therapeutic potential and versatility of this scaffold.137 In the coming years, it is highly likely that further pyrazolo[3,4-d]pyrimidines will be approved for the treatment of cancer patients, especially for indications where there is limited or no targeted therapies available. The gene discussed is BTK; the disease is cancer.