The TKTL1 isoenzyme is missing 38 amino acids in the active site [3] and increased expression of TKT and its isoform TKTL1 has been reported in different types of cancers [4,5,6,7], and is related to malignant transformation [8] and poor prognosis [9,10,11,12]. Here, TKTL1 is linked to cancer.