The objective of this observational study is to evaluate the false positive rate of the blood test based on molecular biomarkers and risk factors. A total of 250 patients diagnosed with various cancers and gastrointestinal diseases will be enrolled. The main question to be answered is

Does the blood test have a low false positive rate in the main study population?

Participants will donate a blood sample as part of their regular medical care for cancer diagnosis and give the consent to know their clinical risk factors.

Inclusion Criteria:

• Patients older than 18 years of age at the time of blood sample collection.
• Subjects must be able to understand the information provided on the participant information sheet, must consent to participate in the study, and must sign the informed consent form.
• Patients diagnosed with only one type of cancer (no colorectal cacner) or gastrointestinal disease.

Exclusion Criteria:

• Patients who have received previous chemotherapy or radiotherapy.
• In case of diagnosis of a tumor: patients who have undergone total or partial surgical resection of the tumor.
• Patients with a personal history of advanced or non-advanced colorectal adenoma, serrated lesions, colorectal cancer, familial adenomatous polyposis or Lynch syndrome.
• Patients without appropriate staging or diagnosis.
• Patients with hemolyzed plasma.

Patients will be enrolled with a only one diagnosis of cancer (no colorectal cancer) or gastrointestinal disease at the time of a consultation within the Oncology, Digestive System, Gastroenterology, Endoscopy or Surgery Service. Patients will be included in a competitive, consecutive and progressive manner by the Centers.