Overall TET2 and IDH1/2 mutations are being mainly described in haematopoietic and brain cancers, but recently, it was shown that 5-hydroxymethylcytosine depletion was detected in those and other cancers such as squamous cell lung cancer, in the absence of TET2 and IDH mutations [149]. This evidence concerns the gene IDH1 and squamous cell lung carcinoma.