Overview
We first collect tumor tissue and adjacent tissue to peform the WES sequencing, then collect blood after postoperative surgery 1, 3. 6, 9, 12, 18, 24 month to detect ctDNA.
Description
ctDNA is obtained from plasma rather than serum, as the latter contains more DNA released from immune cells during clotting. Blood should be drawn into a K2EDTA or cell stabilization tube (e.g., Streck cfDNA collection tube). Plasma isolation should be performed as soon as possible, no later than 24 hours, using K2EDTA (preferably within 4-6 hours) and, if using cell stabilization tubes, within 2-7 days, temporarily stored at 4°C.
Sample disposal procedure: collect whole anticoagulated blood, gently invert to fully anticoagulate, plasma fractionation should be performed as soon as possible, no later than 24 hours, temporarily stored at 4°C using K2EDTA (preferably within 4-6 hours), and stored at -80°C for long term. The collected anticoagulant blood is placed in an ice box containing ice packs and transported vertically to a centrifugable laboratory. Centrifuge at 3000 rpm at 4°C for 15 min, take the upper layer, and aliquot 0.5 mL/tube into 1.5 mL centrifuge tubes. Cryopreserved at -80 °C, 1 mL of whole blood yields approximately 0.5 mL of plasma.
Eligibility
Inclusion Criteria:
(1) Patients with colorectal tumors, whose clinical symptoms meet the diagnostic criteria
of colon cancer in my country, and pathologically diagnosed as colorectal cancer after
surgery; (2) patients with stage II-III colorectal cancer; (3) aged 30-80 years; (4) All
underwent conventional radiotherapy and chemotherapy after operation; (5) Complete clinical
data and follow-up records were available.
Exclusion Criteria:
- (1) Other serious diseases (cardiovascular and cerebrovascular diseases, kidney
diseases, etc.) before operation; (2) Combined with multiple primary colorectal
cancers; (3) Patients with other malignant tumors within the past 5 years; (4)
Combined with digestive tract Obstruction, perforation, bleeding and other indications
for emergency surgery.