Search

Background: DNA methylation biomarkers are one of the most promising tools for the diagnosis and differentiation of adenocarcinomas of the liver, which are among the most common malignancies worldwide. Their differentiation is important because of the different prognoses and treatment options. This study aimed to validate previously identified DNA methylation biomarkers that successfully differentiate between liver adenocarcinomas, including the two most common primary liver cancers, hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), as well as two common metastatic liver cancers, colorectal liver metastases (CRLM) and pancreatic ductal adenocarcinoma liver metastases (PCLM), and translate them to the methylation-sensitive high-resolution melting (MS-HRM) and digital PCR (dPCR) platforms., Methods: Our study included a cohort of 149 formalin-fixed, paraffin-embedded tissue samples, including 19 CRLMs, 10 PCLMs, 15 HCCs, 15 CCAs, 15 colorectal adenocarcinomas (CRCs), 15 pancreatic ductal adenocarcinomas (PDACs) and their paired normal tissue samples. The methylation status of the samples was experimentally determined by MS-HRM and methylation-specific dPCR. Previously determined methylation threshold were adjusted according to dPCR data and applied to the same DNA methylation array datasets (provided by The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO)) used to originally identify the biomarkers for the included cancer types and additional CRLM projects. The sensitivities, specificities and diagnostic accuracies of the panels for individual cancer types were calculated., Results: In the dPCR experiment, the DNA methylation panels identified HCC, CCA, CRC, PDAC, CRLM and PCLM with sensitivities of 100%, 66.7%, 100%, 86.7%, 94.7% and 80%, respectively. The panels differentiate between HCC, CCA, CRLM, PCLM and healthy liver tissue with specificities of 100%, 100%, 97.1% and 94.9% and with diagnostic accuracies of 100%, 94%, 97% and 93%, respectively. Reevaluation of the same bioinformatic data with new additional CRLM projects demonstrated that the lower dPCR methylation threshold still effectively differentiates between the included cancer types. The bioinformatic data achieved sensitivities for HCC, CCA, CRC, PDAC, CRLM and PCLM of 88%, 64%, 97.4%, 75.5%, 80% and 84.6%, respectively. Specificities between HCC, CCA, CRLM, PCLM and healthy liver tissue were 98%, 93%, 86.6% and 98.2% and the diagnostic accuracies were 94%, 91%, 86% and 98%, respectively. Moreover, we confirmed that the methylation of the investigated promoters is preserved from primary CRC and PDAC to their liver metastases., Conclusions: The cancer-specific methylation biomarker panels exhibit high sensitivities, specificities and diagnostic accuracies and enable differentiation between primary and metastatic adenocarcinomas of the liver using methylation-specific dPCR. High concordance was achieved between MS-HRM, dPCR and bioinformatic data, demonstrating the successful translation of bioinformatically identified methylation biomarkers from the Illumina Infinium HumanMethylation450 BeadChip (HM450) and lllumina MethylationEPIC BeadChip (EPIC) platforms to the simpler MS-HRM and dPCR platforms., (© 2024. The Author(s).)

Aim: Identification of aberrant hypermethylation in promoter regions of candidate genes to discover potential biomarkers for colorectal cancer. Materials & Methods: Genes BMP2 , IRF4 , KCNA1 , LRRC7 , NRG3 , SLC27A6 and UNC5D were pre-selected in a bioinformatics study for their hypermethylation status in colorectal cancer. Methylation analysis was performed on 202 cancer tissue specimens to validate candidate genes. Results: Genes KCNA1 and UNC5D displayed methylation in 95.3 and 99.7% of The Cancer Genome Atlas dataset samples and in 96 and 98% of our experimentally tested samples, respectively. Conclusion: KCNA1 and UNC5D promoter hypermethylation holds diagnostic biomarker potential in patients with early colorectal cancer.

The identification of novel genes involved in colorectal cancerogenesis is of high clinical relevance for early diagnosis, applying new therapeutic strategies and monitoring disease recurrence, in order to reduce disease incidence and mortality. Gene silencing through CpG island hypermethylation is a major epigenetic mechanism involved in cancer development. In our study, we aimed to identify and validate novel genes with a tumour specific DNA methylation profile in colorectal cancer. We performed a whole-genome methylation scan and identified several possible candidate genes that are hypermethylated in tumour in comparison to healthy colon mucosa. Using methylation-specific high-resolution melting analysis in a set consisting of 133 colorectal cancer samples, we were able to confirm an altered CpG site in TMEM25 in 69.2% (92/133) tumours analysed. Furthermore, the expression of TMEM25 was found to be significantly lower in tumour tissue. An inverse correlation between hypermethylation of TMEM25 and TMEM25 down-regulated expression was observed. Our results suggest that epigenetic down-regulation of TMEM25 is cancer-related; we thus suggest that TMEM25 hypermethylation might play a significant role in altering expression of this gene in colorectal cancer.

The cytosine–phosphate–guanine (CpG) island methylator phenotype (CIMP) represents one of the pathways involved in the development of colorectal cancer, characterized by genome-wide hypermethylation. To identify samples exhibiting hypermethylation, we used unsupervised hierarchical clustering on genome-wide methylation data. This clustering analysis revealed the presence of four distinct subtypes within the tumor samples, namely, CIMP-H, CIMP-L, cluster 3, and cluster 4. These subtypes demonstrated varying levels of methylation, categorized as high, intermediate, and very low. To gain further insights, we mapped significant probes from all clusters to Ensembl Regulatory build 89, with a specific focus on those located within promoter regions or bound regions. By intersecting the methylated promoter and bound regions across all methylation subtypes, we identified a total of 253 genes exhibiting aberrant methylation patterns in the promoter regions across all four subtypes of colorectal cancer. Among these genes, our comprehensive genome-wide analysis highlights bone morphogenic protein 4 (BMP4) as the most prominent candidate. This significant finding was derived through the utilization of various bioinformatics tools, emphasizing the potential role of BMP4 in colorectal cancer development and progression. [ABSTRACT FROM AUTHOR]

Simple Summary: Malignant liver tumors consist of primary tumors and metastases. A correct diagnosis can be achieved with different methods; one of them is the analysis of the cell-free DNA methylation profile in liquid biopsy, which allows for the detection, characterization, and determination of cancer origin. Our review aims to provide an insight into methylation changes in circulating tumor DNA from patients with different malignant liver tumors and may serve as a starting point for further research. Malignant liver tumors include primary malignant liver tumors and liver metastases. They are among the most common malignancies worldwide. The disease has a poor prognosis and poor overall survival, especially with liver metastases. Therefore, early detection and differentiation between malignant liver tumors are critical for patient treatment selection. The detection of cancer and the prediction of its origin is possible with a DNA methylation profile of the tumor DNA compared to that of normal cells, which reflects tissue differentiation and malignant transformation. New technologies enable the characterization of the tumor methylome in circulating tumor DNA (ctDNA), providing a variety of new ctDNA methylation biomarkers, which can provide additional information to clinical decision-making. Our review of the literature provides insight into methylation changes in ctDNA from patients with common malignant liver tumors and can serve as a starting point for further research. [ABSTRACT FROM AUTHOR]