TERF1 and lung cancer: To address whether the newly identified TRF1 inhibitors were also able to induce DNA damage specifically at telomeres (the so‐called telomere‐induced DNA damage foci or TIFs), we treated CHA9.3 lung cancer cells with all the selected hits for 24 h at 1 μM followed by a double immunofluorescence of the γH2AX to detect DNA damage and of the shelterin component RAP1 to mark the telomeres.