[Mutation, loss of heterozygosity, and expression of tumor suppressor gene ING1 in sporadic colorectal carcinoma].
OBJECTIVE
Inhibitor of growth 1 (ING(1)) gene has been identified as a novel tumor suppressor gene. Its over-expression can inhibit cell growth, and induce cell apoptosis. This study was to explore the effect and significance of ING(1) gene in occurrence and progression of sporadic colorectal cancer.


METHODS
The expression, mutation, and loss of heterozygosity (LOH) of ING(1) gene in 46 specimens of sporadic colorectal cancer tissues and adjuvant normal mucous membrane tissues were detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), PCR-single strain conformation polymorphism (PCR-SSCP), and microsatellite markers, respectively.


RESULTS
(1)The average ratios of light density of p33/ING(1) mRNA, and p47/ING(1) mRNA in the cancerous tissues were significantly lower than those in normal tissues (0.52 vs. 1.28, P < 0.01; 0.51 vs. 1.21, P < 0.01). Difference between the 2 mRNA splices was not significant in the matched tissues (P > 0.05). (2) The average ratios of light density of p33/ING(1) mRNA, and p47/ING(1) mRNA in the cancerous tissues of Dukes' C, D stage were significantly lower than those in cancerous tissues of Dukes' A, B stage (0.38 vs. 0.65, P < 0.01; 0.40 vs. 0.63, P < 0.01). (3) Of the 46 cases, no mutation of ING(1) gene was detected, only 5 (10.9%)cases of LOH were found.


CONCLUSIONS
Abnormal alteration of ING(1) gene is rare in sporadic colorectal cancer. Its down-regulation may happen in transcription or post-transcription, and correlates tightly with the occurrence and progression of sporadic colorectal cancer.
Wei
Jian-Bao
JB
Department of Coloproctological Surgery, The First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, 530021, P. R. China.
Chen
Li-Sheng
LS
Gao
Feng
F
D000328:Adult; D000368:Aged; D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012004:Rectal Neoplasms / Q000235:genetics* / Q000473:pathology; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis* / Q000235:genetics*
C501503:ING1 protein, human; D000076023:Inhibitor of Growth Protein 1; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins