Since a link between telomerase inhibition and DNA damage has been documented [22], the extent of DNA damage induction was comparatively investigated in TERT-positive (A549 and H460) and ALT-positive (U2OS) cancer cells as well as in hTERT-negative normal human bronchial epithelial (NHBE) cells exposed to equitoxic concentrations of tested compounds. Here, GPT is linked to cancer.