To determine whether inhibition of SIK2 kinase activity can sensitize cancer cells to PARP inhibitors, we examined the effect of combining a SIK2 kinase inhibitor (ARN3236 or ARN3261) with the PARP inhibitor olaparib on cell growth in 10 ovarian cancer and 8 TNBC cell lines, as well as in normal ovarian and breast cell lines. This evidence concerns the gene PARP1 and cancer.