Detection of Aneuploidy in Cell Free DNA to Improve the Sensitivity of Diagnostic Peritoneal Lavage in Gastric Cancer

Aneuploidy may be used as a more sensitive diagnostic tool to detect peritoneal metastasis compared to conventional cytology and imaging techniques. Our aim is to establish whether aneuploidy as detected in cfDNA (as a measure for ctDNA) in PLF of patients with GC may hold value as an additional staging and tumor evaluation method in GC patients.

Gastric cancer patients: Inclusion Criteria: * Age ≥18 years old; * Written informed consent according to the ICH-GCP and national/local regula-tions. Exclusion Criteria: \- Language difficulty, dementia or altered mental status prohibiting the under-standing and giving of informed consent. non-cancer controls: Inclusion criteria: * Operable patients who will undergo a planned diagnostic laparoscopy for a benign indication bariatric or gallbladder disease); * Age ≥18 years old; * Written informed consent according to the ICH-GCP and national/local regulations. Exclusion criteria: * Active inflammation or infection; * Subjects with previous malignancies are excluded unless a complete remission was achieved at least 5 years prior to study entry (exceptions include but are not limited to, non-melanoma skin cancers; in situ bladder cancer, or in situ co-lon cancers; in situ cervical cancers/dysplasia; or breast carcinoma in situ).