Rad51 is the ssDNA binding protein and recombinase responsible for strand invasion and homology searching in HR,177,178 which is often upregulated in radio- and chemo-resistant cancers.8 Several small molecule compounds were identified that inhibit Rad51–ssDNA binding, preventing the nucleoprotein filament formation (reviewed by Budke et al.210). This evidence concerns the gene RAD51 and cancer.