Studies on microsatellite instability in p16 gene and expression of hMSH2 mRNA in human gastric cancer tissues.
OBJECTIVE
To detect the loss of heterozygosity (LOH) frequency of microsatellite sites D9s171, D9s1604 of p16 gene and expression of hMSH2 mRNA in various differentiated types of gastric cancer, adjacent cancer tissues and normal gastric mucosa.


METHODS
LOH was detected by polymerase chain reaction (PCR)-denaturing polyacrylamide gel electrophoresis-silver staining. The expression of hMSH2 mRNA was examined with in situ hybridization.


RESULTS
The frequency rate of LOH was significantly higher in gastric cancers than that in adjacent cancer tissues (P=0.032). No significant difference was noted among various differentiated types and various clinical stages of gastric cancers. The significantly reduced expression of hMSH2 mRNA positive signal cells exhibited in gastric cancers, in comparison with that in the adjacent cancer tissues and normal gastric mucosa, respectively (P=0.001). No significant difference was noted among various clinical stages of gastric cancers (P>0.05). The difference of positive signal cells in poorly differentiated cancers and those in well and moderately differentiated cancers were significant (P<0.001).


CONCLUSIONS
The frequencies of LOH in two microsatellite sites, D9s171 and D9s1604, in p16 genome were associated with development of gastric cancer and no significant correlation was demonstrated between the LOH frequency and the cell differentiated types of tumor cells or clinical stages. There was a positive relationship between the expression of hMSH2 mRNA and the differentiated types of gastric cancer.
Zhang
Qin-Xian
QX
Molecular Cell Biology Research Center, Medical College of Zhengzhou University; 40 Daxue Lu, Zhengzhou 450052, Henan Province, China. qxz53@zzu.edu.cn
Ding
Yi
Y
Le
Xiao-Ping
XP
Du
Peng
P
D004268:DNA-Binding Proteins; D019942:Genes, p16; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats / Q000235:genetics*; D051718:MutS Homolog 2 Protein; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics* / Q000378:metabolism*
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C497172:MSH2 protein, human; D051718:MutS Homolog 2 Protein