Homologous recombination, a critical step of DSB repair, was inhibited when nuclear cGAS compacted DNA or interfered with the function of a DNA repair enzyme.67,75 As genome instability promotes tumorigenesis, nuclear cGAS may have a protumor function.67 As cGAS in tumor cells has both anti- and protumor roles based on its localization, it is important to understand how cGAS localization is regulated among tumor cells. Here, LIG4 is linked to neoplasm.