The present study confirms that not only does gefitinib potently inhibits GAK, but also other clinical kinase inhibitors, such as dasatinib a tyrosine kinase inhibitor approved for the treatment of CML (chronic myelogenous leukaemia) and Ph+ALL (Philadelphia chromosome-positive acute lymphoblastic leukaemia), as well as sunitinib another tyrosine kinase inhibitor approved for the treatment of RCC (renal cell carcinoma) and imatinib-resistant GIST (gastrointestinal stromal tumour), inhibit GAK even more potently. This evidence concerns the gene GAK and hereditary clear cell renal cell carcinoma.