Cancer is one of the gene diseases. The genome stability is closely associated with the occurrence of cancers. XRCC1 gene is one of the DNA repair genes. It participates in the repair process when the genome is injured. So it is considered important in maintaining the stability of the genome and in the prevention of tumor occurrence. This article introduced the characteristic of XRCC1 gene, the relationship between single nucleotide polymorphism of the gene and susceptibility to tumor, and the common methods used in the XRCC1 research.

Background and purpose:Although cervical lymph node metastases is commonly found, papillary thyroid cancer(PTC) has a fairly good prognosis. The microarray or gene chip technique is an effective method to explore the biological behavior of cancers. This study aims to measure the differential expression of genes between papillary thyroid cancer with lymph node metastasis and normal thyroid tissue with the new technology. Methods:The total mRNA was extracted from the specimens of papillary thyroid cancer with lymph node metastasis and normal thyroid tissues. Both of samples were labeled with fluorescent Cy5 or Cy3, and then hybridized to the gene chip which it includes 14 112 human functional gene fragments. Differentially expressed genes were screened out by scanning and analyzing the fluorescent signals.Results:There are 1 212 differentially expressed gene fragments between the two groups that it account for 8.71% of the total sites. Among them, 22 sites showed remarkable difference with either upregulation or downregulation more than 8 times fold, 2 of 6 downregulation sites represent one same gene sequence: NM-001920, which is the mRNA of the protein decorin.Conclusions:Gene chip is an effective method to study the change of gene expression during the progression of a disease. As to PTC, it involves many genes. Decorin may be an important biomarker for the prediction of metastases to the cervical lymph nodes in PTC.

Objective To explore the effect of norcantharidin (NCTD) on proliferation and apoptosis of implanted human gallbladder carcinoma in nude mice. MethodsGBC-SD cells of human gallbladder carcinoma were implanted subcutaneously into nude mice. Mice were randomly divided into control, 5-FU, NCTD and NCTD+5-FU -treatment groups. Tumor size, growth curve and inhibitory rate was respectively evaluated. Cell cycle and apoptosis were measured. Morphological changes of tumorous cells were observed. ResultsLD_ 50 of NCTD for nude mice was 139.96mg?kg -1. Tumor volume (5.61?0.39cm3 vs. 9.78?0.61cm3, P=0.000), percentage of the S phase cells (43.47%?2.83% vs. 69.85%?1.96%, P=0.000) in NCTD group was smaller than that in control group, with tumor inhibitory rate (42.63% vs. 0, P=0.012) and cell apoptosis rate (5.49%?0.59% vs. 15.08%?1.49%, P=0.000) being increased. Compared with other groups,the difference on tumor volume (4.51?1.11 cm3), tumor inhibitory rate (53.89%), percentage of the S phase cells (33.76%?2.39%) and cell apoptosis rate (18.68%?2.38%) in NCTD+5-FU group was statistically significant (P=0.000), with increased nuclear shrinkage, karyorrhexis and typical apoptosis. Conclusion NCTD inhibits the growth of implanted tumor of human gallbladder carcinoma in nude mice. The inhibitory effect could be intensified when combined with 5-FU.