In view of the lack of replicative ability and non-toxicity to cultured CT26 cells of UV-Tianjin, we hypothesized that the possible mechanism of UV-Tianjin–induced apoptosis might be that UV-Tianjin RNA fragments are recognized by RIG-I and then the activation of the RIG-I/MAVS pathway triggers cancer cell-selective apoptosis. The gene discussed is RIGI; the disease is cancer.