The ALT pathway has been found in ~10%–15% cancers and is usually characterized by the presence of ALT-associated promyelocytic leukemia (PML) bodies (APBs), extrachromosomal telomeric repeats (ECTR), and high frequency of telomere sister chromatid exchange (T-SCE) in cells (Cesare and Reddel, 2010). This evidence concerns the gene GPT and acute promyelocytic leukemia.