TLK1 and triple-negative breast carcinoma: MDA-MB-436, a triple negative breast cancer (TNBC) cell line with a natural BRCA1 mutation and the highest expression of TLK1 among the CCLE cell lines (Fig. 3B), exhibited significantly higher sensitivity to olaparib than MDA-MB-468, a BRCA1-proficient TNBC cell line, in a cell survival assay (Fig. 3D and E).