6-thioguanine selectively kills BRCA2-defective tumors and overcomes PARP inhibitor resistance. by Issaeva, N, Thomas, H, Djureinovic, T, Djurenovic, T, Jaspers, J, Stoimenov, I, Kyle, S, Pedley, N, Gottipati, P, Zur, R, Sleeth, K, Chatzakos, V, Mulligan, E, Lundin, C, Gubanova, E, Kersbergen, A, Harris, A, Sharma, R, Rottenberg, S, Curtin, N, Helleday, T