Pilot Study by Liquid Biopsy in Gastrointestinal Stromal Tumors: Analysis of PDGFRA D842V Mutation and Hypermethylation of SEPT9 Presence by Digital Droplet PCR.

Tissue biopsy remains the standard for diagnosing gastrointestinal stromal tumors (GISTs), although liquid biopsy is emerging as a promising alternative in oncology. In this pilot study, we advocate for droplet digital PCR (ddPCR) to diagnose GIST in tissue samples and explore its potential for early diagnosis via liquid biopsy, focusing on the PDGFRA D842V mutation and SEPT9 hypermethylated gene. We utilized ddPCR to analyze the predominant PDGFRA mutation (D842V) in surgical tissue samples from 15 GIST patients, correlating with pathologists' diagnoses. We expanded our analysis to plasma samples to compare DNA alterations between tumor tissue and plasma, also investigating SEPT9 gene hypermethylation. We successfully detected the PDGFRA D842V mutation in GIST tissues by ddPCR. Despite various protocols to enhance mutation detection in early-stage disease, it remained challenging, likely due to the low concentration of DNA in plasma samples. Additionally, the results of Area Under the Curve (AUC) for the hypermethylated SEPT9 gene, analyzing concentration, ratio, and abundance were 0.74 (95% Confidence Interval (CI): 0.52 to 0.97), 0.77 (95% CI: 0.56 to 0.98), and 0.79 (95% CI: 0.59 to 0.99), respectively. As a rare disease, the early detection of GIST through such biomarkers is particularly crucial, offering significant potential to improve patient outcomes.

The value of plasma SEPT9 gene methylation combined with serum carcinoembryonic antigen and carbohydrate antigen 724 in the diagnosis of colorectal cancer / 肿瘤研究与临床

Objective:To investigate the clinical application value of plasma SEPT9 gene methylation combined with serum carcinoembryonic antigen (CEA) and carbohydrate antigen 724 (CA724) in the diagnosis of colorectal cancer.Methods:A total of 219 patients with colorectal diseases in Baoji Central Hospital and Yunnan Province New Kun Hua Hospital from May 2018 to October 2021 were selected, including 149 cases of colorectal cancer and 70 cases of colorectal polyp diagnosed by pathology. A total of 100 healthy people in the same period were selected as the healthy control group. The methylation of SEPT9 gene in plasma was measured by using real-time fluorescent polymerase chain reaction (PCR), and the levels of serum CEA and CA724 were measured by using electrochemiluminescence. The expressions of three indicators in each group were compared, and the effect of every single indicator and the combination of the three indicators on the diagnosis of colorectal cancer was analyzed by using receiver operating characteristic (ROC) curve.Results:The positive rate of SEPT9 gene methylation in colorectal cancer group (74.50%, 111/149) was higher than that in colorectal polyp group (22.86%, 16/70) and healthy control group (1.00%, 1/100), and the difference was statistically significant ( P < 0.001). The positive rate of CEA in colorectal cancer group (46.98%, 70/149) was higher than that in colorectal polyp group (40.00%, 28/70) and the healthy control group (3.00%, 3/100) and the difference was statistically significant ( P < 0.001). The positive rate of CA724 in colorectal cancer group (38.93%, 58/149) was higher than that in colorectal polyp group (32.86%, 23/70) and the healthy control group (2.00%, 2/100), and the difference was statistically significant ( P < 0.001). The area under the curve (AUC) of ROC of SEPT9 gene methylation, CEA and CA724 in the single diagnosis of colorectal cancer was 0.823 (95% CI 0.753-0.891), 0.788 (95% CI 0.725-0.852) and 0.689 (95% CI 0.624-0.754), respectively. The optimal cut-off Ct value of SEPT9 gene methylation in the diagnosis of colorectal cancer was 36.5, the sensitivity was 90.30%, and the positive predictive value was 84.68%, which were higher than those of CEA and CA724. The optimal cut-off value of CEA in the diagnosis of colorectal cancer was 8.80 ng/ml, and the specificity (77.50%) and negative predictive value (78.48%) were higher than those of SEPT9 gene methylation and CA724. The sensitivity (97.66%), positive predictive value (93.98%), negative predictive value (81.25%) and AUC (0.846, 95% CI 0.749-0.944) of the combined detection of the three indexes taking the optimal cut-off value of every single indicator were higher than those of the single indicator. Conclusions:The combined detection of plasma SEPT9 gene methylation, CEA and CA724 in the diagnosis of colorectal cancer has high sensitivity and accuracy. The three combined detection can complement each other and improve the diagnostic efficiency, which is of high clinical value for the diagnosis of colorectal cancer.

Application of methylation detection of SEPT9 gene in early diagnosis of colorectal cancer / 国际肿瘤学杂志

SEPT9 gene belongs to a member of SEPT gene family.In recent years,it has been found that SEPT9 gene is highly methylated in colorectal cancer cells.Detecting SEPT9 gene methylation in the development of colorectal cancer,the application of different specimen types for the detection of SEPT9 gene methylation and the development of SEPT9 gene methylation detection methods can provide evidence for early diagnosis of colorectal cancer.

Progress in Application of Peripheral Blood Methylated SEPT9 Gene Assay for Colorectal Cancer Screening / 胃肠病学

The early detection and diagnosis of colorectal cancer (CRC)is of great clinical importance. Peripheral blood methylated SEPT9 gene was found to be a sensitive and specific biomarker for CRC and was superior to other commonly used screening methods such as fecal occult blood test,serum tumor markers and colonoscopy in a variety of studies. But it is of limited value in screening of adenomas,polyps and other precursors of CRC,and its capacities for assessment of cancer recurrence and therapeutic effects of radiotherapy and chemotherapy need further clinical validation. This article reviewed the progress in application of peripheral blood methylated SEPT9 gene assay for CRC screening.

Progress in Application of Peripheral Blood Methylated SEPT9 Gene Assay for Colorectal Cancer Screening / 胃肠病学

The early detection and diagnosis of colorectal cancer (CRC)is of great clinical importance. Peripheral blood methylated SEPT9 gene was found to be a sensitive and specific biomarker for CRC and was superior to other commonly used screening methods such as fecal occult blood test,serum tumor markers and colonoscopy in a variety of studies. But it is of limited value in screening of adenomas,polyps and other precursors of CRC,and its capacities for assessment of cancer recurrence and therapeutic effects of radiotherapy and chemotherapy need further clinical validation. This article reviewed the progress in application of peripheral blood methylated SEPT9 gene assay for CRC screening.

Advances in Study on SEPT9 Gene Methylation in Diagnosis of Colorectal Cancer / 胃肠病学

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies with poor prognosis and high mortality.SEPT9 gene is a tumor suppressor gene and plays an important role in the end of cell division.Studies have shown that methylation of SEPT9 gene could be used in the early diagnosis of CRC.This article reviewed the advances in study on SEPT9 gene methylation in the screening and diagnosis of CRC.