Expression of tumor related gene NAG6 in gastric cancer and restriction fragment length polymorphism analysis.
OBJECTIVE
NAG6 gene is a novel tumor related gene identified recently. This study was designed to examine the expression of this gene in gastric cancer and corresponding normal tissues, and to investigate its role in the occurrence and development of gastric cancer, also to study if the genetic structure of NAG6 was altered in gastric cancer.


METHODS
Reverse transcription-polymerase chain reaction (RT-PCR), Northern blot analysis and dot hybridization were used to compare the expression level of NAG6 gene in 42 cases of gastric cancer tissues with their corresponding normal tissues of the same patients respectively. In addition, restriction fragment length polymorphism (RFLP) analysis was adopted to study if the genetic structure of NAG6 was altered in gastric carcinomas.


RESULTS
The expression of NAG6 in 57.1% gastric cancer tissues (25/42) was absent by RT-PCR analysis. The down-regulation rate of NAG6 in gastric cancer tissues was significantly higher than that in corresponding normal tissues (P<0.01). However no correlation between the down-regulation of NAG6 and lymph-node and/or distance metastasis was found in this study (P>0.05). Dot hybridization confirmed the results of RT-PCR. Furthermore, the results of EcoRI RFLP analysis of NAG6 gene demonstrated that 3 of 7 cases of gastric cancer showed loss of 5 kb fragment in comparison with their corresponding normal tissues.


CONCLUSIONS
NAG6 gene is significantly down regulated in gastric cancer. The loss of genetic materials may be the cause of down-regulation of NAG6 expression. This seems to suggest that NAG6 may represent a candidate of putative tumor suppressor gene at 7q31-32 loci associated with gastric carcinoma. The down-regulation of this gene may play a role in occurrence and development of this disease, however it may not be associated with lymph node and/or distance metastasis.
Zhang
Xiao-Mei
XM
Department of Digestive Medicine, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China.
Sheng
Shou-Rong
SR
Wang
Xiao-Yan
XY
Bin
Liang-Hua
LH
Wang
Jie-Ru
JR
Li
Gui-Yuan
GY
D000328:Adult; D000368:Aged; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D012150:Polymorphism, Restriction Fragment Length; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D014018:Tissue Distribution
C491796:CCDC136 protein, human; D009363:Neoplasm Proteins