Evaluation of the Combination of APC and DCC Gene Methylation in the Early Diagnosis of Lung Cancer / 现代检验医学杂志

Objective To investigate the significanceof both the adenomatous polyposis coli (APC)and deleted in colorectal carcinoma (DCC)gene methylation in the early diagnosis of lung cancer.Methods 245 patients with lung cancer and 150 patients with non-malignant lung disease patients and 40 healthy volunteers were drawn for the experiment.A methylation specific PCR (MSP)was used to detect the methylation status of APC and DCC in the peripheral blood.Results The posi-tive rates of APC and DCC genes promoter methylation Peripheral blood of patients with lung cancer were 26.53% (65/245)and 36.33% (89/245),respectively.The positive rates of APC and DCC genes promoter methylation Peripheral blood of patients with benign lung diseases were 2.67% (4/150),8.00%(12/150),respectively.The positive rates of APC and DCC genes promoter methylation Peripheral blood of healthy volunteers were 0.There was a significant difference between patients with the lung cancer,those with the benign lung diseases and Healthy volunteers (P 0.05).There was no correlation between methylation test results and pa-tient gender,age,pathological type,pathological grade,TNM stage and so on (P >0.05).Conclusion APC and DCC gene methylation were closely related to the development of non-small cell lung cancer.They can be used as an early diagnostic marker of lung cancer.

Effects of DCC gene on biological behaviors of colorectal carcinoma cell line SW1116 / 国际肿瘤学杂志

Objective To investigate the effects of exogenous wild DCC gene stably transfection on growth of colorectal carcinoma cell line SW1116 in vitro. Methods DCC gene domain was amplified from human normal colon tissue by reverse transcript-polymerase chain reaction(RT-PCR). At first,a recombinant expression plasmid pcDNA3. 1( + )-DCC was constructed. Human colorectal carcinoma cell line SW1116 with-out DCC gene was transfected with pcDNA3. 1-DCC. Cell viability was tested by methyl thiazolyl tetrazolium (MTT)assay. Immunofluorescence staining was used to determine the effects of pcDNA3. 1-DCC and expres-sion of carcino-embryonic antigen(CEA)in human colorectal carcinoma cell line SW1116 which was transfect-ed with pcDNA3. 1-DCC. Results The population of cells transfected with pcDNA3. 1( + )-DCC plasmid was lower than those with pcDNA3. 1( + )-DCC plasmid and normal cells(t = 3. 645,P ﹤ 0. 05;t = 3. 132,P ﹤0. 05)at 3 ~ 6 days after transfection,and the proliferation rate of cells transfected with pcDNA3. 1( + )-DCC plasmid was lower than those with pcDNA3. 1( + )plasmid and normal cells(t = 2. 134,P ﹤ 0. 05;t = 2. 736, P ﹤ 0. 05). Cell line SW1116 transfected with pcDNA3. 1( + )-DCC plasmid total viability was lower than nor-mal cells(t = 3. 053 ,P ﹤ 0. 05)at 2 ~ 6 days after transfection. Cell line SW1116 transfected with pcDNA3. 1 ( + )-DCC plasmid total viability was lower than those with pcDNA3. 1( + )plasmid(t = 2. 816,P ﹤ 0. 05)at 2,4,5,6 days after transfection. The population of flavo-green colour cells transfected with pcDNA3. 1( + )-DCC plasmid and the fluorescent intensity of these cells were lower than those with pcDNA3. 1( + )plasmid and normal control cells. Conclusion Transfected DCC gene can suppress the cell proliferation and make CEA expression of cell line SW1116 down regulation to weaken its infiltration and metastasis abilities.

Preliminary screening for microsatellite instability and loss of heterozygosity in the deleted in colorectal cancer (DCC) gene among Filipino patients with colorectal adenocarcinoma

OBJECTIVE: This study aimed to detect the presence of microsatellite (MSI) and loss of heterozygosity (LOH) of the Deleted in Colorectal Cancer (DCC) gene in normal and tumor tissues of Filipino colorectal cancer patients and examine its correlation with age, gender, tumor grade, tumor stage and site of lesion.METHODS: Paired frozen normal and tumor tissues from thirtynine (39) patients with colorectal adenocarcinoma were used by polymerase chain reaction (PCR). Single strand conformation polymorphism - polyacrylamide gel electrophoresis (SSCP - PAGE) was used to determine MSI and restriction fragment length polymorphism (RFLP) was used to study LOH.RESULTS: Based on our data, out of the 39 patients, 10 showed LOH of the DCC gene using the LOH markers VNTR, M2 and M3, while no MSI was detected in the samples using the MSI markers BAT25 and BAT26. Correlation with clinicopathological characteristics showed that there is significance for the site of lesion. The LOH has correclation with tumor samples from the colon but not with those from the rectum.CONCLUSION: Preliminary screening for MSI and LOH of the DCC gene shows that occurrences of colorectal cancer among Filipino patients can be correlated with LOH of the DCC gene with colorectal cancer in a Filipino sample population.

Role of DCC(Deleted in Colorectal Cancer) Gene in Oral Squamous Cell Carcinoma

Chromosome 18q alteration plays a key role in colorectal tumorigenesis, and loss of heterozygosity at 18q is associated with a poor prognosis in colon cancer. DCC(Deleted in Colorectal Cancer) is a putative tumor- suppressor gene at 18q21 that encodes a transmembrane protein with structural similarity to neural cell adhesion molecule that is involved in both epithelial and neuronal cell differentiation. DCC is implicated in regulation of cell growth, survival and proliferation. Thus, tumor progression in squamous cell carcinoma, stomach cancer, colorectal cancer correlates with downregulation of DCC expression. The mechanism for DCC suppression is associated with hypermethylation of the DCC gene promoter region. Hence, the goal of this study is to identify the promoter methylation responsible for the down-regulation of DCC expression in oral squamous cell carcinoma. 12 of tissue specimens for the study are excised and gathered from 12 patients who are diagnosed as SCC in department of OMS, dental hospital, dankook university. To find expression of DCC in each tissue samples, immunohistochemical staining, RT-PCR gene analysis and methylation specific PCR are processed. The results are as follows. 1. In the DCC gene RT-PCR analysis, 5(41.6%) of 12 specimens of oral squamous cell carcinoma did not expressed DCC gene. 2. In the promoter methylation specific PCR analysis, 5(41.6%) of 12 specimens showed promoter methylation of DCC gene. 3. In the immunohistochemical staining of poor differentiated and invasive oral squamous cell carcinoma, loss of DCC expression was observed. These findings suggest that methylation of the DCC gene may play a role in loss of gene expression in invasive oral squamous cell carcinoma.

DCC Gene and Protein Expression in Colorectal Cancer

PURPOSE: The germline, or somatic, inactivation of tumor suppressor genes, through point mutation, or deletion, plays an important role in carcinogenesis. Several gene alterations, such as adenomatous polyposis coli (APC), deleted in colorectal cancer (DCC) and p53, have been detected in the development of colorectal cancer. Within these genes, a loss of heterozygosity (LOH) at the DCC gene locus was frequently associated with colorectal tumors, and the LOH of the DCC gene, and the expression of the DCC protein, might be related to malignant formation and metastasis. The aim of this study was to determine the DCC LOH and the expression of DCC protein in colorectal cancers, and evaluate their prognostic value and relationship with the clinicopathological data. MTHODE: Fifty colorectal cancer tissues were obtained from resected specimens. Using formalin-fixed paraffin- embedded sections as a source of DNA, we examined the DCC protein in the tissue through immunohistochemical stainings and immunoblotting analysis, the DCC LOH through a polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP). RESULTS: DCC LOH was observed in 24 of the 50 patients (48.0%). The expression of the DCC protein was decreased in the cancer tissue (62.3 23.6%) compared with the adjacent normal mucosa inform the immunoblotting analysis. A decreased DCC protein expression was also observed from the immunohistochemistry, which coincided with the immunoblotting analysis. However, both the DCC LOH and the decreased DCC protein were not related to the clinical and pathological parameters, such as location of tumor, tumor size, histological type and the venous, and lymphatic invasions. There were significant correlations between the DCC protein expression and tumor progression, and hematogenous metastasis (P<.05). CONCLUSIONS: A decreased expression of the DCC protein was noted in human colorectal cancers, and there was a significant relationship between the expression of the DCC protein and distant metastasis, but there was no correlation between the DCC LOH and distant metastasis. These results suggest that the expression of the DCC protein might be related to tumor progression and metastatic potential, and the DCC protein immunoreactivity may be a useful prognostic factor in patients with colorectal cancers.

Study on loss of heterozygosity at the DCC locus in gastric cancer / 中华消化杂志

This article is to evaluate the role of DCC gene alteration in the development and progression of gastric cancer, as well as to correlate with its prognosis. Loss of heterozygosity (LOH) at DCC gene was examined in 45 cases of surgically resected gastric cancer tissue. LOH at the DCC locus was detected in 15/45(33.3%), and it was found to be closely related to clinical staging, but not to the histologic types, depth of tumor invasion or lymph node metastases. These results suggest that LOH at the DCC locus occurs in late stage of the disease and detection of LOH at the DCC locus may be useful for predicting the prognosis of the gastric cancer patients.