To better understand human cellular responses to telomeric DSBs in G1, we investigated enzymatically induced (EN-T) telomere-targeted DSBs, specifically in telomerase-positive BJ1-hTERT (normal) and EJ-30 (bladder cancer) cells, and in U2OS (ALT, osteosarcoma) cells. The gene discussed is GPT; the disease is urinary bladder cancer.