The assessment of microsatellite alterations in the plasma DNA as biomarkers for the detection of high risk groups and micrometasasis of hepatocellular carcinomas

• Main Author: 蔡季妙
• Other Authors: 簡一治
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/67165390474884614297

碩士 === 國立彰化師範大學 === 生物學系 === 92 === Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, especially in Asia and Africa. It is strongly associated with persistent hepatitis B or C virus infection, exposure to α-toxin B1 (AFB1). It has been hypothesized that the development of cancers was majorly due to accumulated genetic alterations in the genome, which eventually caused inactivation of tumor suppressor genes and activation of oncogenes. Early diagnosis of occurrences and micro-metastasis of cancer patients is always the major topic in cancer clinic. It is reasonable to assume that if we can detect cancer cells in peripheral blood of cancer patients, implying that they have high probability to have cancer metastasis. The phenomena of loss of heterozygosity (LOH) and microsatellite instability (MSI) in cancer cells are derived from the accumulation of genetic alterations. Both have been widely accepted as biomarkers of cancer cells. For the purpose of identifying the biomarkers for detecting micro-metastasis of cancer cells, we designed the present study to determine the presence of tumor DNA in the plasma of patients with hepatocellular carcinomas (HCC), characterized by LOH in 6 microsatellite markers. DNA extracted from tumor tissues, neighboring normal tissues, blood cells and plasma of 44 cancer patients was amplified with fluorescent primers specific for the microsatellite markers. DNA extracted from blood cells and plasma of 37 normal individuals was also analyzed as normal controls. PCR amplicons were separated on the ABI-3100 16 capillary array electrophoresis instrument and analyzed with GeneScan analysis software v.3.7. To our surprise, high incidence of LOH was detected in the marker of D4S426, and revealed no significant difference with that was detected in patients. We found that the presence of LOH of D17S849 (p=0.048) and D4S426 (p=0.021) in HCC tumors was associated with the tumor sizes; and that of D16S3091 was related to HCC patients, who were positive in HBsAg (p=0.03). Further, the incidence of LOH of all the microsatellite markers analyzed in HCC tumors was increased with tumor stages (p=0.01). As a conclusion, we have identified the first grade biomarkers in detection of micro-metastasis of HCCs to be D16S3091 and D17S849. We also suggested that both D16S3091 and D17S849 were the suitable biomarkers in detecting the high-risk HCC groups in normal individuals (p=0.001).