OVERVIEW
The Septin9 Colorectal Cancer Blood Screening Kit is a real-time fluorescence PCR assay for the qualitative detection of methylated Septin9 (SEPT9) DNA in bisulfite-converted cell-free DNA extracted from human peripheral blood plasma. By pairing bisulfite conversion with TaqMan probe chemistry, the assay detects methylated CpG sites within the SEPT9_v2 region on the FAM channel while co-amplifying the ACTB housekeeping gene on the CY5 channel as an internal control. The kit is intended as a non-invasive, blood-based adjunct to colonoscopy to aid in the early detection of colorectal cancer and other digestive tract tumors.
WHY BLOOD-BASED COLORECTAL CANCER SCREENING?
Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related death worldwide. Prognosis is highly stage-dependent — five-year survival exceeds 90% when CRC is caught at stage I but drops below 15% at stage IV. Yet population adherence to colonoscopy, the gold-standard screening modality, remains below 50% in most regions because of its invasive nature, bowel preparation burden, and risk of complications. A blood-based screening test offers an easy-to-collect, high-compliance alternative that can triage average-risk and high-risk individuals to colonoscopy only when molecular evidence supports it.
WHY METHYLATED SEPTIN9?
SEPT9 is a member of the septin family of GTP-binding cytoskeletal proteins encoded on chromosome 17q25.3. Aberrant hypermethylation of the SEPT9 promoter region, particularly the v2 transcript region rich in CpG sites, is a recurring epigenetic event in colorectal and other digestive tract tumors. Methylated SEPT9 DNA is shed by apoptotic and necrotic tumor cells into the bloodstream as short cell-free DNA fragments, where it can be captured from a standard plasma sample. Because methylation patterns are tissue- and tumor-specific, methylated SEPT9 functions as a highly specific molecular marker for CRC and is one of the pre-test items recommended for guiding colonoscopy referral.
KEY FEATURES
- Bisulfite-conversion chemistry that converts unmethylated cytosine to uracil while leaving methylated cytosine intact, enabling specific amplification of the methylated SEPT9_v2 region
- Dual-channel TaqMan detection — FAM reports methylated SEPT9, CY5 reports ACTB as the internal control for sample quality and adequate DNA input
- Closed-tube workflow with positive and negative external controls to safeguard against contamination and instrument failure
- Analytical sensitivity of 30 pg/mL RKO methylated DNA (≥95% detection rate at the LoD)
- Precision CV of 1.68% – 2.59% across three manufacturing lots at both high (2500 copies/test) and low (100 copies/test) target concentrations
- No cross-reactivity with non-target methylation markers (RAR-β, HOXA9, MGMT, APC, P16, CDH13), non-human genomic DNA (E. coli, S. aureus), or other digestive-tract samples
- No interference from bilirubin (4 mg/dL), triglyceride (500 mg/dL), hemoglobin (10 g/dL), fluorouracil (120 mg/mL), oxaliplatin (26 mg/mL), or calcium folinate (120 mg/mL)
- Available in liquid and lyophilized formats; 20, 50, and 100 tests per kit
CLINICAL PERFORMANCE
Multicenter evaluation across three independent Chinese clinical sites — Zhejiang Cancer Hospital (477 samples), Sir Run Run Shaw Hospital (250 samples), and Shanghai 10th People's Hospital (299 samples), totaling 1,026 valid clinical samples — produced the following performance against clinical diagnosis:
- Colorectal cancer preoperative group (73 cases): 54 true positives, 19 false negatives → clinical sensitivity 73.97%
- Non-related disease group (225 cases): 207 true negatives, 18 false positives → clinical specificity 92%
- Adenoma and other benign colorectal diseases: specificity 79.73%
- Other malignant tumors: specificity 97.12%
- Healthy individuals: specificity 100%
The kit is CE marked and validated as a pre-colonoscopy examination item in published colorectal cancer screening pathways.
SPECIFICATIONS
- Product name: Human Methylated Septin9 DNA Detection Kit (Real-time PCR), liquid and lyophilized forms
- Catalog numbers: 20 / 50 / 100 tests per kit
- Specimen: peripheral blood plasma (10 mL whole blood collected in Streck, BD K2EDTA, or equivalent cell-free DNA tubes; plasma separated within 2 hours of collection)
- Workflow timing: bisulfite conversion approximately 4 hours + purification 0.5 hour + real-time PCR 1.5 hours; total approximately 6 hours, with a 2-hour option for fully manual processing
- Compatible real-time PCR instruments: Applied Biosystems 7500, Roche LightCycler 480, Hongshi SLAN-96S (FAM + CY5 channels required)
- Storage: liquid kit at ≤-20°C, shelf life 9 months, validated for up to 5 freeze-thaw cycles; lyophilized kit at 2-30°C in a dampproof environment, shelf life 12 months
- Plasma stability: 2-8°C for up to 18 hours; -15°C to -25°C for up to 28 days
TARGET USERS
The kit is designed for clinical laboratories, hospital体检中心, screening program operators, gastroenterology and oncology departments, colorectal cancer early-detection centers, and molecular diagnostics providers running blood-based CRC screening, high-risk population triage to colonoscopy, post-treatment surveillance, and adjunct diagnosis of digestive tract malignancies.