TERT and squamous cell carcinoma: Barthel et al. [49] analyzed the TERT gene amplification in the TCGA cohort including 6835 patients and covering 31 tumor types, and the findings are summarized as follow: (i) A total of 4% the examined tumors exhibit a TERT gene amplification, with high frequency in ovarian cancer, adrenocortical carcinoma, esophageal cancer, lung adenocarcinoma, and squamous carcinoma (Fig. 3c); (ii) TERT amplification is observed in 3% of TERT-expressing tumors; and (iii) The highest telomerase activity is found in tumors with a TERT amplification.