Transketolase like -1 ( TKTL1 ) is a related enzyme transketolase and catalyzes the same reactions as the latter. While transketolases be formed in many living organisms, this enzyme has evolved only in mammals. There are at least three isoforms of the human TKTL1, which are located respectively in different tissue types, namely heart, brain, lung, kidney, placenta, pancreas, and muscles. Moreover, the enzyme is found in various neurodegenerative diseases, diabetes mellitus, and some cancers. Especially in fast-growing, malignant tumor cells, it is responsible for its biochemical property, embark on an anaerobic pathway also with sufficient oxygen supply; the TKTL1 can thus called glucose fermentation in tumor cells explain ( Warburg hypothesis ).

Similarly, the overexpression of TKTL1 protein is discussed in several tumor types as a potential marker for the clinical outcome or a potential target for tumor therapy. After all, could experimentally the mRNA transcripts of TKTL1 in a cell culture of human hepatoma ( HepG2 ) are inhibited with iRNA Even as a tumor marker in the clinical course of some cancers could TKTL1 play a role, so maybe even with throat cancer.