Expression of tumor related genes NGX6, NAG-7, BRD7 in gastric and colorectal cancer.
OBJECTIVE
NGX6, NAG-7 and BRD7 genes are tumor related genes, which have been newly cloned by positional candidate cloning strategy. This study was designed to investigate the expression levels of NGX6, NAG-7 and BRD7 genes in human gastric and colorectal cancer tissues, and their corresponding normal tissues, and to investigate whether these genes play a role in the pathogenesis of gastric and colorectal cancers.


METHODS
Reverse transcription-polymerase chain reaction (RT-PCR), dot hybridization and Northern blot analysis were used to compare the expression levels of NGX6, NAG-7 and BRD7 genes in 34 gastric cancer tissues and 34 colorectal cancer tissues with their corresponding normal tissues of the same patients, respectively.


RESULTS
Among the 34 colorectal cancer specimens and the 34 gastric cancer specimens, the expression of NGX6 in 25 colorectal cancer tissues was absent or very weak (73.5 %) by RT-PCR analysis. The down-regulation rate of NGX6 in colorectal cancer tissues was significantly higher than that in corresponding normal tissues (26.5 %,9/34) (P<0.005). Moreover, the down-regulation of NGX6 was significantly correlated with lymph node and/or distance metastases. Patients with lymph node and/or distance metastasis had much higher down-regulation rate of NGX6 than patients without metastases (93.8 % vs 55.6 %, P<0.05). However no correlation was found between the expression of NGX6 and pathologic type of colorectal cancer in this study, and also the expression of NGX6 did not display any difference between gastric cancer and corresponding normal tissues (58.8 % vs 70.6 %, P>0.25). Dot hybridization and Northern blot analysis confirmed the results of RT-PCR. Furthermore, NAG-7 and BRD7 mRNA was not up- or down-regulated in gastric and colorectal cancers compared with their corresponding normal tissues in our study.


CONCLUSIONS
The down-regulation of NGX6 may be closely associated with tumorigenesis and metastasis of colorectal carcinoma. However, it may not contribute to the development and progression of gastric carcinoma. In addition, the expression levels of NAG-7, and BRD7 did not alter in gastric and colorectal cancers. This seems to suggest that NAG-7 and BRD7 genes may not play a role in gastric and colorectal carcinogenesis.
Zhang
Xiao-Mei
XM
Department of Digestion Medicine, The Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China.
Wang
Xiao-Yan
XY
Sheng
Shou-Rong
SR
Wang
Jie-Ru
JR
Li
Jiang
J
D015152:Blotting, Northern; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000235:genetics*; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D009687:Nuclear Proteins; D009693:Nucleic Acid Hybridization / Q000379:methods; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics*; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D000092468:Bromodomain Containing Proteins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D008565:Membrane Proteins; D009687:Nuclear Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D025521:Tumor Suppressor Proteins; C485694:BRD7 protein, human; D000092468:Bromodomain Containing Proteins; C470228:LINC00312 long non-coding RNA, human; C477325:TMEM8B protein, human