GPT and cancer: A small number of human cancers, such as adrenocortical carcinoma, neuroblastoma cell tumor, osteosarcoma, and astrocytoma, rely on the alternative lengthening of telomerase (ALT) pathway to cause telomere shortening, despite the fact that the majority of human malignancies (>85%) use telomerase to lengthen telomeres 3, 7-9.