Consistently, we found that intraperitoneal administration of IPI-504 substantially reduced the orthotopic tumor burden in mice transplanted with SK-BR-3 (R175H) and BT-549 (R249S) cells, while only minor repression of the growth of MDA-MB-468 (R273H) and MCF-7 (WT) tumors was observed, suggesting that IPI-504 rendered tumor cells with mutant p53 aggregates hypersensitive to chemotherapy (Figure 6C and Figure S5C). This evidence concerns the gene TP53 and neoplasm.