BRCA1 and breast cancer: Another example for SL in the context of deficient HRR is the DNA repair enzyme polymerase Q (POLQ).17 POLQ has been shown to be overexpressed and upregulated in numerous cancer types including breast cancer and PCa.17 A synthetic lethal interaction has been observed between POLQ inhibition and BRCA1/2 mutations.17 The development of POLQ inhibitors for the treatment of patients with BRCA mutations is currently ongoing and will hopefully reach clinical trials soon.