Studies have shown that PARP inhibitors such as NU1025 11 and 2-(4-hydroxyphenyl)-1H-benzo[d]imidazole-7-carboxamide (NU1085) 22 (see Figure 10) significantly enhance the exposure of tumor cells to topoisomerase I inhibitors, such as topotecan 18 (see Figure 9). This evidence concerns the gene PARP1 and neoplasm.