Application of multiplex methylated-specific PCR with capillary electrophoresis to explore prognostic value of TSGs hypermethylation for hepatocellular carcinoma

Liquid biopsy with cell free DNA: new horizons for prostate cancer

Although prostate cancer (PCa) is one of the most common tumors in European males, the only minimally invasive diagnostic tool in PCa setup is the determination of PSA in serum. Cell-free DNA (cfDNA) has been demonstrated to be helpful for PCa diagnosis but has not yet been integrated into the clinical setting. This review aims to provide a systematic update of cfDNA and its fragmentation patterns in PCa reported in literature published over the last twenty years. Due to the high variability of the scientific methods adopted and a lack of standardized median cfDNA levels, results fluctuate across different studies. These differences may be due to the cfDNA source, the quantification method, or the fragmentation pattern. Blood plasma is the most frequently analyzed biological fluid, but seminal plasma has been reported to contain higher cfDNA concentration due to its vicinity to the tumor origin. CfDNA has been shown to be composed of single-stranded (ssDNA) and double-stranded DNA (dsDNA), so the total cfDNA concentration should be preferred as it corresponds best to the tumor mass. Fluorometry and capillary electrophoresis (CE) may be quick and cost-effective tools for cfDNA assessment in a clinical setting. The greatest future challenge is the elaboration of common guidelines and standardized procedures for diagnostic laboratories performing cfDNA analysis. A multiparametric approach combining the analysis of total cfDNA (both ssDNA and dsDNA), cfDNA fragment length, and specific genetic mutations (ctDNA assessment) is required for optimal future applications of liquid biopsy.

Consecutive and automatic detection of multi-gene mutations from colorectal cancer samples by coupling droplet array-based capillary electrophoresis and PCR-RFLP

The efficacy of targeted therapy is associated with multi-gene mutation status. Carrying out effective multi-genotyping analysis in combination has been a challenge in clinical settings. We therefore developed a droplet-based capillary electrophoresis (CE) system coupled with PCR-restriction fragment length polymorphism (PCR-RFLP) technology to detect multi-gene mutations from a small volume of samples. A 16 × 16 200-nL droplet array for sample encapsulation was constructed on a glass chip. The electrophoresis system consisted of a tapered vertical capillary filled with polyvinylpyrrolidone, a laser-induced fluorescence detector, and a high voltage power supply. Notably, a droplet-based electrokinetic sample introduction method and a "∩" shape capillary were developed to facilitate consecutive droplet sampling using a home-made automatic control module. The DL2000 DNA marker was consecutively separated, achieving high migration time and plate number reproducibility. The system was further applied to detect PCR-RFLP products. For colorectal cancer (CRC) cell lines, KRAS, BRAF, and PIK3CA were genotyped with a sensitivity of 0.25%. For CRC patient specimens, 30 samples were consecutively and automatically multi-genotyped without inter-sample contamination, with a lowest mutation frequency of 0.37%. For the first time, we developed a droplet-based CE system for consecutive DNA analysis with low sample consumption. This automated CE system could be further developed to integrate the full process of gene mutation detection, serving as a more effective platform for individualised therapy.

Application of multiplex methylated-specific PCR with capillary electrophoresis to explore prognostic value of TSGs hypermethylation for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignant tumor that severely threatens human health. To date, early detection for HCC patients is particularly significant due to their poor survival rates even after liver resection.

METHODS

Therefore, an efficient and sensitive detection method for monitoring liver cancer, multiplex methylation-specific PCR (MSP) coupled with capillary electrophoresis, is developed.

RESULTS

Simulations demonstrated that the methylation status of RASSF1A, p16, SFRP1, and ELF could be detected even when DNA equaled or exceeded 12.5 ng simultaneously. Also, its accuracy for methylation detection outweighed polyacrylamide gel electrophoresis (87.5%) and agarose electrophoresis (84.3%), reaching 92.1%. Subsequently, we implemented multiplex MSP with capillary electrophoresis to investigate methylation status of the four tumor suppressor genes in tissue specimens and explore the prognostic value for HCC patients. As the data suggested, multivariate cox regression analysis revealed that the recurrence-free survival of 46 patients was greatly associated with portal vein tumor thrombus (PVTT) and p16 methylation and receiver operating characteristic (ROC) curves demonstrated that the predictive range of portal vein tumor thrombus (PVTT) combined with p16 hypermethylation was more sensitive than that of either PVTT or p16 hypermethylation alone with regard to disease recurrence in patients with HCC, which could be testified as a valuable biomarker in Clinical application.

CONCLUSION

Multiplex MSP coupled with capillary electrophoresis has an excellent prospect of clinical application for monitoring early liver cancer and screening valuable biomarkers for prognosis of HCC patients.