RPA1 and gastrointestinal stromal tumor: Given that DNA end resection is known as an early step in HR during which the broken DNA ends are converted into a long stretch of 3′-ended single-stranded DNA (ssDNA) and taking into account that after end resection, the ssDNA is coated with RPA, we initially assessed the impact of FGFR inhibition on formation of ssDNA by BrdU incorporation and RPA foci formation in GIST treated with Dox.