LIG1 and breast cancer: Secondly, our findings show six genes from the NER pathway induced by PAC exposure in breast-cancer cells, only ERCC1 and PNKP were observed in both types of cell lines, and only LIG1 was seen to be increased by PAC in MCF-7, while ERCC2, RFC1, and POLL were upregulated by treatment with PAC treatment in MDA-MD-321.