XRCC4 and ovarian cancer: Indeed, the reciprocal immunoprecipitation of XRCC4 and LIG4 confirm that lactate markedly enhanced the interaction between XRCC4 and LIG4, with lactate treatment strongly promoting the interaction (Figure 3A,B), and LDHi treatment markedly suppressing the interaction (Figure 3C,D), respectively, in ovarian cancer cells.