Evaluation of the Idylla system for rapid detection of POLE mutations in colorectal and endometrial cancers

Pathogenic exonuclease domain mutations in POLE define a hypermutated subtype of colorectal and endometrial cancers, with prognostic and therapeutic implications, particularly for immunotherapy. Detection currently relies on next-generation sequencing, which is sensitive but costly and time-consuming. The Idylla™ POLE-POLD1 Mutation Assay (Biocartis) is a fully automated real-time PCR for rapid detection of hotspot mutations, but its performance has not been fully evaluated.We retrospectively analyzed a cohort of 40 patients to evaluate the performance of the Idylla™ assay. All tumors underwent targeted NGS of POLE exons 9-14. DNA from formalin-fixed paraffin-embedded tissue was analyzed with the Idylla™ assay and results were compared with NGS. The assay's limit of detection was also determined.The Idylla™ assay detected POLE hotspot variants with 96% sensitivity and 100% specificity. Limit of detection experiments indicated reliable detection only in samples with DNA concentration > 5 ng/µL and tumor cell content > 20%.The Idylla™ POLE-POLD1 Mutation Assay enables rapid, robust detection of POLE hotspot variants in colorectal and endometrial cancers, with high concordance to NGS. Integrating Idylla as a front-line screening tool could accelerate molecular classification, though NGS remains necessary for samples with low tumor content or low DNA input.