The Application of Liquid Biopsy for the Development and Validation of a Non-Invasive Screening and Diagnosis Test for Endometrial Premalignant and Malignant Lesions: A Prospective Innovative Pilot Study

: Background/Objectives: Endometrial cancer (EC) is a common malignancy in developed countries, with incidence closely linked to lifestyle factors and genetic predispositions, notably Lynch syndrome. Traditional biopsy methods for diagnosis and monitoring are invasive. This study aims to develop and validate a non-invasive diagnostic method for EC using liquid biopsy, specifically examining circulating tumor DNA (ctDNA) for its potential in early detection and disease monitoring. Methods: A cohort of 63 patients with EC or atypical endometrial hyperplasia (AEH) was recruited from the Gynecological Unit of the Azienda Ospedaliera Universitaria Federico II. Plasma samples were processed to extract ctDNA, which was sequenced and analyzed for mutations. Matched tumor tissue and germline DNA were also examined to confirm mutation concordance and assess potential genetic predispositions. Results: Pathogenic mutations were identified in plasma ctDNA in 59 out of 63 cases (93%), with a 65% concordance between plasma ctDNA mutations and those found in solid tumor samples. Key mutations in genes such as PTEN, PIK3R1, and KMT2C were significantly associated with a higher tumor grade and advanced stage disease, such as myometrial infiltration. Conclusions: Liquid biopsy shows promise as a minimally invasive diagnostic and monitoring tool for EC, offering real-time insights into tumor biology. The high mutation concordance between the plasma ctDNA and tumor tissue underscores the potential of a liquid biopsy in managing EC, particularly for patients at risk of recurrence. Further longitudinal studies are needed to establish ctDNA as a standard tool in EC diagnosis and monitoring.