OTI-611 is cytotoxic to TNBC tumor organoids, potently inhibiting the viability with half maximal inhibitory concentration (IC50) values of 1.7 μM (BRCA1-mutant HR-deficient SUM149PT), 2.8 μM (BRCA1-mutant HR-deficient HCC1937), and 3.3 μM (BRCA-wildtype HR-proficient MDA-MB-231) (Figure S1). Here, BRCA1 is linked to neoplasm.