Circulating tumor DNA (ctDNA) is emerging as a novel biomarker for tumor evaluation, offering advantages such as high sensitivity and specificity, minimal invasiveness, and absence of radiation. Currently, various techniques including gene sequencing and PCR are employed for ctDNA detection. The utilization of ctDNA for monitoring minimal residual disease (MRD) enables comprehensive assessment of tumor status and early identification of tumor recurrence, achieving a remarkable detection sensitivity of 0.01%. Therefore, ctDNA holds promise as a biomarker for early diagnosis, treatment response monitoring, and prognosis prediction in solid tumors. This article reviews the commonly used methods for detecting ctDNA and their advantages in evaluating tumor MRD and guiding clinical diagnosis and treatment.
Humans ; Circulating Tumor DNA/genetics* ; Neoplasm, Residual/genetics* ; Biomarkers, Tumor/genetics* ; Neoplasm Recurrence, Local ; Prognosis

DNA Methylation ; DNA, Neoplasm ; genetics ; Genomics ; trends ; Human Genome Project ; Humans ; Neoplasms ; genetics ; Research

OBJECTIVETo investigate relationship between methylation status of the APC and Bikunin CpG islands and clinicopathological characteristics of breast carcinomas.

METHODSThe methylation status of APC and Bikunin CpG islands in 152 sporadic breast carcinoma samples were analyzed by methylation specific PCR.

RESULTS40.8% of breast carcinomas examined showed methylated signals for the APC. The methylation frequency of APC was significantly correlated to the tumor size (chi(2) = 4.041; P = 0.044), but not to patients' age, pathologic type of tumor, clinical stage, histological grade, lymph node metastasis and the status of estrogen or progestogen receptor. In addition, 24.6% of carcinoma samples examined revealed strong methylated signals for Bikunin. No significant correlation was found between the aberrant methylation of Bikunin and the clinicopathological characteristics of sporadic breast carcinomas.

CONCLUSIONThe aberrant methylations of APC and Bikunin are frequent events during breast carcinogenesis. APC methylation might play a role in the progression of breast cancer.

Breast Neoplasms ; genetics ; pathology ; CpG Islands ; DNA Methylation ; DNA, Neoplasm ; genetics ; Female ; Follow-Up Studies ; Humans

No abstract available.
DNA, Neoplasm/genetics ; High-Throughput Nucleotide Sequencing/*methods ; Humans ; Sequence Analysis, DNA/methods ; Urologic Neoplasms/*genetics

Carcinoma, Hepatocellular ; genetics ; Cloning, Molecular ; DNA, Complementary ; genetics ; Genes, Neoplasm ; genetics ; Humans ; Liver Neoplasms ; genetics

OBJECTIVETo make quantitative analysis of DNA content of breast cancer with neuroendocrine (NE) cells and its significance.

METHODSUsing MIPS-III image analyzer, DNA content and 9 parameter measurements of the tumor nuclei were made in both NE positive (17) and negative (64) breast carcinomas.

RESULTSOut of 81 breast carcinomas, 17 cases were NE positive while 64 cases were NE negative. In the NE (+) cases, the integral optic density, mean optic density, DNA index, DNA stemlines peak, > 5c aneuploidy cells and the rate of aneuploidy cells were all lower than those in the NE negative breast carcinoma cases (P < 0.01). The positive rates of NE cells were 32.5% and 7.9% in grade I - II breast carcinomas and in grade III breast carcinomas respectively with significant difference between the two groups (P < 0.01).

CONCLUSIONOur study shows that NE (+) breast carcinomas have lower DNA parameters than NE (-) breast carcinomas, suggesting that NE (+) breast carcinomas have lower malignancy.

Aneuploidy ; Breast Neoplasms ; genetics ; pathology ; Carcinoma, Neuroendocrine ; genetics ; pathology ; DNA, Neoplasm ; genetics ; metabolism

OBJECTIVETo screen methylations of CpG islands in prostate cancer using restriction landmark genomic scanning (RLGS).

METHODSThe DNA was extracted from homogeneous cells captured by laser capture microdissection in 20 prostate cancer and 18 benign prostatic hyperplasia (BPH) tissues for scanning the CpG islands using RLGS. The methylation status of each CpG island was compared between the cancer and BPH samples to screen the genes involved in prostate cancer development. The screened genes were uploaded to DAVID database for GO analysis, and the genes with the most significant methylation were analyzed by pyrosequencing.

RESULTS AND CONCLUSIONAmong all the tested CpG islands, 10245 (37.2%) in prostate cancer and 8658 (30.3%) in BPH samples were found to be abnormally methylated, and >60% of the methylated CpG islands were in the promoter region. Compared with BPH samples, the prostate cancer samples showed differential methyation in 735 CpG islands, including 458 hepermethyated and 256 hypomethelated ones. Seven genes (DPYS, P16, APC, GSTP1, TMEM122, RARB, and ARHGAP20) in prostate cancer were identified to have distinct methylations. Bioinformatics analysis suggested that these genes were associated with several biomolecular and biological processes, and among them DPYS gene was involved in 13 GO anotated biologic functions, development of 50 diseases and 47 protein interactions. Pyrosequencing of 7 sites of the CPG island in DPYS gene showed a methylation frequency of 32.7%, suggesting the importance of DPYS gene in the carcinogenesis and progression of prostate cancer.

CpG Islands ; DNA Methylation ; DNA, Neoplasm ; genetics ; Genomics ; Humans ; Male ; Polymerase Chain Reaction ; Prostatic Hyperplasia ; genetics ; Prostatic Neoplasms ; diagnosis ; genetics

Carcinoma, Hepatocellular ; genetics ; metabolism ; DNA Methylation ; DNA Restriction Enzymes ; metabolism ; DNA, Neoplasm ; genetics ; Glutathione S-Transferase pi ; genetics ; metabolism ; Humans ; Liver Neoplasms ; genetics ; metabolism ; Polymerase Chain Reaction ; methods

PURPOSE: Gastric carcinoma tissues release high level of prostaglandin E2 (PGE2) when compared to non-neoplastic mucosa, and cyclooxygenase-2 (COX-2), which is the rate-limiting enzyme in prostaglandin (PG) biosynthesis, is often overexpressed in gastric carcinomas and during gastric carcinogenesis. However, little is known about the expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the key enzyme responsible for the biological inactivation of PG, in gastric carcinomas. MATERIALS AND METHODS: We investigated the expression of 15-PGDH in 28 cases of advanced gastric carcinomas by Western blot analysis and also the relation between its expression and the gene promoter methylation. RESULTS: 15-PGDH expression was significantly decreased in gastric carcinomas compared to corresponding non-neoplastic tissues and inversely correlated with the expression of proliferating cell nuclear antigen in gastric carcinomas. However, there was no correlation between 15-PGDH expression and pathological findings such as nodal metastasis and vascular invasion. Promoter hypermethylation of 15-PGDH gene was not detected in carcinomas, with only a negligible expression of the enzyme. CONCLUSION: Our results suggested that 15-PGDH has tumor suppressor activity in gastric carcinomas.
Aged ; Base Sequence ; DNA Methylation ; DNA Primers/genetics ; DNA, Neoplasm/genetics ; Female ; Humans ; Hydroxyprostaglandin Dehydrogenases/genetics/*metabolism ; Male ; Middle Aged ; Promoter Regions, Genetic ; Stomach Neoplasms/*enzymology/genetics

Several reports have described aberrant methylation in various types of human cancers. However, the interpretation of methylation frequency in various human cancers has some limitations because of the different materials and methods used for methylation analysis. To gain an insight into the role of DNA hypermethylation in human cancers and allow direct comparison of tissue specific methylation, we generated methylation profiles in 328 human cancers, including 24 breast, 48 colon, 61 stomach, 48 liver, 37 larynx, 24 lung, 40 prostate, and 46 uterine cervical cancer samples by analyzing CpG island hypermethylation of 13 genes using methylation-specific PCR. The mean numbers of methylated genes were 6.5, 4.4, 3.6, 3.4, 3.1, 3.1, 3.1, and 2.1 in gastric, liver, prostate, larynx, colon, lung, uterine cervix, and in breast cancer samples, respectively. The number of genes that were methylated at a frequency of more than 40% in each tumor type ranged from nine (stomach) to one (breast). Generally genes frequently methylated in a specific cancer type differed from those methylated in other cancer types. The findings indicate that aberrant CpG island hypermethylation is a frequent finding in human cancers of various tissue types, and each tissue type has its own distinct methylation pattern.
Quantitative Trait Loci/*genetics ; Polymerase Chain Reaction ; Neoplasms/*genetics ; Humans ; Genetic Predisposition to Disease/genetics ; Gene Frequency/genetics ; DNA, Neoplasm/*genetics ; *DNA Methylation ; CpG Islands/*genetics ; Chromosome Mapping/*methods