Expression and clinicopathological significance of Mel-18 and Bmi-1 mRNA in gastric carcinoma.
BACKGROUND
The Polycomb group (PcG) genes are a class of regulators responsible for maintaining homeotic gene expression throughout cell division. PcG expression is deregulated in some types of human cancer. Both Bmi-1 and Mel-18 are of the key PcG proteins. We investigate the expression and clinicopathological roles of Mel-18 and Bmi-1 mRNA in gastric cancer.


METHODS
The expression of Mel-18 and Bmi-1 in a series of 71 gastric cancer tissues and paired normal mucosal tissues distant from the tumorous lesion was assayed by quantitative real time RT-PCR. The correlation between Mel-18 and Bmi-1 mRNA expression, and between Mel-18 or Bmi-1 mRNA level and clinicopathological characteristics were analyzed.


RESULTS
Expression of Mel-18 and Bmi-1 genes was variably detected, but overexpression of Bmi-1 mRNA and decreased expression of Mel-18 mRNA were the most frequent alteration. In addition, the expression of Bmi-1 and Mel-18 mRNA inversely correlates in gastric tumors. Moreover, a significant positive correlation between Bmi-1 overexpression and tumor size, depth of invasion, or lymph node metastasis, and a significant negative correlation between Mel-18 low-expression with lymph node metastasis or the clinical stage were observed.


CONCLUSIONS
Our data suggest that Mel-18 and Bmi-1 may play crucial but opposite roles in gastric cancer. Decreased Mel-18 and increased Bmi-1 mRNA expression was associated with the carcinogenesis and progression of gastric cancer. It is possible to list Bmi-1 and Mel-18 as biomarkers for predicting the prognosis of gastric cancer.
Department of Medical Oncology, Fudan University Shanghai Cancer Center; China. guoweijian1@sohu.com.
You-Wei
YW
Lu
Jin
J
Li
Wei-Jian
WJ
Guo
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis*; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D009687:Nuclear Proteins; C489348:PCGF2 protein, human; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1