Vacutainer ppt plasma preparation tube

Venous blood was drawn from PTC and HC patients. All peripheral venous blood samples (10 mL) were collected in EDTA (BD Vacutainer PPT™ Plasma Preparation Tube; 13 × 100 mm/5 mL) tubes and separated by the ugation 1900× g for 10 min at 4 °C. Supernatant was then transferred to a new 15 mL conical tube and centrifuged at 16,000× g for 10 min at 4 °C. Purified plasma was transferred to 1.5 mL aliquots and stored at −80 °C until nucleic acid purification.
Thyroid cancer tissue and corresponding adjacent normal tissue were snap-frozen and stored at −80 °C in liquid nitrogen before DNA extraction. Corresponding adjacent normal tissue was removed at least 5 mm away from the primary tumor. Afterward, an experienced pathologist reviewed tissue samples of thyroid cancer tissues consisting of at least 80% cancer cells. Cancer cells were absent in adjacent normal tissue.

Ten milliliters (ml) of whole blood was extracted from the elbow vein of each diabetic patient and healthy control under fasting condition immediately after the diagnosis of diabetic complications during follow-up and at the end of follow-up. Blood was kept at room temperature in BD Vacutainer® PPT™ Plasma Preparation Tube for 30 min. After that, blood was centrifuged at 1600 g for 20 min to collect plasma.

Serum carcinoembryonic antigen (CEA) level was measured at baseline. For ctDNA analysis, blood samples were collected 1–2 weeks before initiation of preoperative therapy (baseline) and after treatment (just before surgery) for some patients. Blood samples were collected into BD Vacutainer® PPT™ plasma preparation tubes (2 × 5 mL) (BD Biosciences, Franklin Lakes, NJ, USA). Plasma was extracted by centrifugation at 1100 rcf for 10 min at room temperature and stored at −20 °C according to laboratory protocol. The samples were purified using PromegaInstrument Maxwell^® RSC (Promega Corporation, Madison, WI, USA). Libraries from cfDNA were prepared with Oncomine Lung cfDNA Assay (Thermo Fisher Scientific, Waltham, MA, USA), available in the laboratory for the most common mutations in rectal cancer. The cfDNA panel used in this study covered 11 genes (ALK, BRAF, EGFR, ERBB2, KRAS, MAP2K1, MET, NRAS, PIK3CA, ROS1 and TP53), with more than 150 hotspots (SNVs and short indels). We tracked the mutations with the highest mutation allele frequency (MAF) in each patient [63 (link)]. Patients with detectable mutations were categorized “ctDNA positive”, and the ones with undetectable mutations were characterized as “ctDNA negative”.