Several small molecule cancer drugs are represented in this review, including tyrosine kinase (TK) inhibitors,33,42,44,48-50 proteosome inhibitors,16,33,43,44 phosphoinositide 3-kinase (PI3K) inhibitors,42 B-cell lymphoma-2 (BCL-2) inhibitors,44 protein kinase B-raf (BRAF) inhibitors,51 mitogen-activated protein kinase (MEK) inhibitors,51 and Hedgehog pathways (HH) inhibitors.32 This evidence concerns the gene TKT and cancer.