NGS can also be used as a cross-validation technique in cases of validation of the method, a great example being the cross-validation of droplet digital PCR (ddPCR) for the real-time detection of ESR1 mutation in the PADA-1 trial (PAlbociclib and Circulating Tumor DNA for ESR1 Mutation Detection) [89]. This evidence concerns the gene ESR1 and neoplasm.