Detection of MYCN Amplification in Serum DNA Using Conventional Polymerase Chain Reaction

Neuroblastoma (NB) is the most common extra-cranial solid tumor of childhood and is characterized by a wide range of clinical behaviors. Amplification of MYCN is a well-known poor prognostic factor in NB patients. As the MYCN amplification status is usually tested using tumor specimens, lengthy and invasive procedures are unavoidable. To evaluate the possibility of detecting MYCN amplification without invasive procedure, we performed conventional polymerase chain reaction (PCR) analysis to identify MYCN amplification using the preserved serum DNA. PCR of serum DNA was done in 105 NB patients whose MYCN status had been confirmed by fluorescence in situ hybridization. MYCN amplification was evaluated as the ratio of signal intensities between MYCN and NAGK (M/N ratio). When regarding the tissue FISH results as a reference, 10 patients had MYCN-amplified (MNA) NB, and 95 had non-MNA NB. The M/N ratio of the MNA group (median 2.56, range 1.01-3.58) was significantly higher than that of the non-MNA group (median 0.97, range 0.67-5.18) (P < 0.001). In the receiver operating characteristic curve analysis, the area under the curve was 0.957 (95% confidence interval 0.898-1.000; P < 0.001), and it showed 90.9% sensitivity and 97.9% specificity with the selected cut-off value set as 1.6. The detection of MYCN amplification using conventional PCR analysis of serum samples seems to be a simple and promising method to evaluate the MYCN status of NB patients. Further study with a larger set of patients is needed to confirm the accuracy of this result.

Detection of Serum Free DNA Hypermethylation in Surgically Resected Adenocarcinoma of the Lung

PURPOSE : Aberrant DNA methylation patterns have been commonly associated with human cancers. We have investigated the frequency of DNA hypermethylation in promoter regions from adenocarcinomas of the lung and then attempted to detect the same epigenetic changes from patient serum samples. MATERIALS AND METHODS : We collected tissues from 72 cases of lung adenocarcinomas. The cancer and normal lung tissues were tested for DNA hypermethylation using methylation-specific PCR (MSP). The genes investigated were DAPK, RARbetaP2 and p16. We selected 12 patients where promoter hypermethylation was present for all three genes and four patients where hypermethylation was not seen for any of the three genes. Serum-free DNA was extracted and was tested for promoter hypermethylation. The status of serum-free DNA methylation was analyzed; the hypermethylation status was compared to clinical variables and cancer outcomes. RESULTS : DNA hypermethylation was observed in 32% of samples for DAPK, 63% of samples for RARbetaP2 and 83% of samples for p16 from the cancer tissues. Among the 12 matched serum samples where the primary tumor showed hypermethylation in all three gene promoter regions, we were able to detect five incidences of serum DNA hypermethylation in four patients. The four patients had TNM stage II or higher disease. None of the patients with stage I disease showed serum-free DNA hypermethylation. CONCLUSION : Aberrant promoter hypermethylation was frequently observed in surgically resected adenocarcinoma of the lung. Concurrent serum-free DNA hypermethylation was detected in 34% of patients where the primary tumor showed hypermethylation in all three gene promoter regions. The findings suggest that the serum-free DNA methylation status might be used as a potential target for the diagnosis of lung cancer. However, the low sensitivity should be improved for use in a clinical application

The research of serum-DNA IgH and T-cell receptor gama gene rearrangement in lymphogenous malignant patients / 中华检验医学杂志

Objective To evaluate the diagnostic significance of detecting serum-DNA concentration and clonal gene rearrangement in lymphogenous malignant patients.Methods Serum-DNA in 72 diagnosed patients were measured and analyzed by SPSS11.0.Serum and mono-nuclear cells samples were collected. IgH CDRⅢ, TCR?V9 region were amplified by PCR.Results The serum-DNA concentration of disease groups were (418?172)?g/ml,(426?192)?g/ml, (388?170)?g/ml and(400?110)?g/ml, each was higher than those of control group(77?47)?g/ml(P0.05).Conclusion The concentration of serum-DNAwere higher in lymphogenous malignant patients and tumor associated DNA could be easily detected, so they have important diagnostic value in lymphogenous malignant patients.

Aberrant Promoter Methylation of Death-Associated Protein Kinase in Serum DNA from Lung Cancer Patients / 결핵

BACKGROUND: Promoter methylation of tumor suppressor genes is one of the key epigenetic changes in many human cancers. The aim of this study was to evaluate the promoter methylation status of the Death-associated protein(DAP) kinase gene, which played an important role in lung cancer, in the serum DNA of primary lung cancer patients. METHODS: This study investigated the aberrant methylation of DAP kinase in the serum of 65 primary lung cancer patients by methylation-specific PCR (MSP). RESULTS: Methylation in the serum was detected in 29 of 65(44.6%) for DAP kinase. There was no statistical association between methylation of DAP kinase and age, smoking history, histologic type, or stage. Methylation of DAP kinase was found more frequently in men (p=0.044). CONCLUSIONS: This study suggests that the aberrant methylation of the DAP kinase promoter is readily detectable in the serum DNA of lung cancer patients using MSP analysis.