Cui Xuemei, Department of Clinical Laboratory, Characteristic Medical Center (formerly 306 Hospital).
Edited by Liu Yan/Cui Yan, Medical Science Popularization Center
"Food first" – the gut plays a vital role in our daily lives, it is responsible for converting food into nutrients and removing metabolic by-products. Maintaining intestinal health not only helps digestion and absorption, but also helps us defend against harmful substances.
With the improvement of socio-economic level, the excessive intake of various high-salt, high-sugar, high-purine and high-fat foods greatly increases the risk of bowel cancer. Bowel cancer is the third leading cause of cancer-related deaths worldwide, and the incidence of bowel cancer is increasing year by year worldwide. In mainland China, the incidence of bowel cancer ranks second in malignant tumors, second only to lung cancer, and has become the second biggest killer of people's lives and health!
Overview of bowel cancer
Colorectal cancer, also known as colorectal cancer (CRC), is a malignant tumor originating from the epithelial tissue of the colon or rectal mucosa, and more than 60% of colorectal cancers occur in the rectum and sigmoid colon. The early symptoms of bowel cancer are very similar to common gastrointestinal diseases, such as abdominal discomfort, dull pain, bloating, changes in bowel habits, etc., which are often thought to be minor problems, and they will be cured after two days and are not taken seriously. By the time obvious symptoms of discomfort appear, it is often in the middle and advanced stages, so the best time for treatment is missed. Fortunately, the process of normal colorectal mucosa from "hyperplasia→ adenoma formation →cancer" generally takes 5~10 years, which provides an important time window for early diagnosis and treatment intervention of bowel cancer. As long as it is detected early, the cure rate of early bowel cancer is as high as 90%. Therefore, bowel cancer screening should be "early"!
Early screening method and characteristics
At present, the accepted gold standard for screening is colonoscopy, but many people often resist it due to factors such as difficulty in making appointments, cumbersome bowel preparation before examinations, and poor experience. The fecal occult blood test is inexpensive, but it has limited sensitivity and specificity.
With the development of molecular diagnostic technologies such as PCR, the Septin9 gene methylation test, a screening method with higher sensitivity and specificity for early colorectal cancer, has begun to emerge. This is a non-invasive, non-invasive, and simple early screening, auxiliary diagnosis and efficacy monitoring technology for colorectal cancer, which can assist in the diagnosis and detection of ultra-early colorectal cancer lesions.
Septin9甲基化检测简介
Studies have confirmed that Septin9 plays a role as a tumor suppressor gene in the occurrence and development of colorectal cancer, and is involved in chromosome segregation, DNA repair, apoptosis and other processes. Gene methylation is a hallmark change in the early stages of cancer, and the degree of methylation is closely related to disease progression, tumor size, and malignancy.
Septin9 gene methylation is a specific molecular marker in the early occurrence and development of colorectal cancer. Detection of methylated Septin9 gene fragments in the blood can be used for early diagnosis of colorectal cancer.
Compared with traditional screening methods, the Septin9 methylation test has the following advantages: (1) safety—it is more private and safe than colonoscopy; (2) Convenient - sampling is convenient and fast, only one tube of peripheral blood is needed; (3) Early stage - the sensitivity is high, and increases with the increase of clinical stage, and the early detection rate is significantly higher than that of traditional fecal occult blood test; (4) Specific: Septin9 gene methylation is present in colorectal cancer at different stages, and the detection rate is not affected by age, gender and lesion location.
Interpretation of Septin9 methylation assay results
Negative test result (-): Methylation of the Septin9 gene was not detected in the blood.
Positive test result (+): Methylation test results are not conclusive in the diagnosis of colorectal cancer, and if the results are positive, further colonoscopy is required. Other diseases such as chronic gastritis, lung cancer, breast cancer, and pregnancy can also be positive.
Suitable for testing
(1) ≥ 40 years old and have anorectal symptoms for ≥ 2 weeks.
(2) History of chronic intestinal diseases, with diarrhea, blood in the stool, constipation, weight loss, etc.
(3) Resistant to colonoscopy, or have contraindications to colonoscopy.
(4) People with a family history of tumors.
(5) People with bad living habits, high stress, and unbalanced diet.
(6) Postoperative monitoring of colon cancer patients, used for efficacy evaluation and follow-up monitoring.
(The picture comes from the Internet)