Lower expression level of RAD51, a homologous recombination (HR) repair factor, was also observed in C4I, when compared to SiHa….where a higher level of apoptotic response was found in C4I (21.12%) compared to SiHa (6.37%). These findings suggested that there was a reduced HR activity in C4I and might explain the higher sensitivity to olaparib compared to SiHa. We also demonstrated the therapeutic potential of olaparib in cervical cancer, and the rationale of using RAD51 as a predictive biomarker for olaparib sensitivity.