Mitochondrial uncoupling protein 2 expression in colon cancer and its clinical significance.
OBJECTIVE
To detect the expression of mitochondrial uncoupling protein 2 (UCP2) in colon cancer and analyze the relation between UCP2 expression and clinical pathological features of colon cancer.


METHODS
Fifteen colon tissue samples and 15 its adjacent tissue samples were obtained from colon cancer patients during surgical interventions. UCP2 expression was detected with immunohistochemical method in 10 normal controls, 10 hyperplastic polyp patients, 20 tubular adenoma patients and 78 colon cancer patients. Patients with rectal cancer were excluded. Quantitative reverse transcription polymerase chain reaction and Western blotting were used to detect UCP2 expressions in colon cancer tissue samples and its adjacent tissue samples. Relation between UCP2 expression and clinical pathological features of colon cancer was also analyzed.


RESULTS
The UCP2 mRNA expression level was four-fold higher in colon cancer tissue samples than in its adjacent tissue samples. The UCP2 protein expression level was three-fold higher in colon cancer tissue samples than in its adjacent normal tissue samples. The UCP2 was mainly expressed in cytoplasm. The UCP2 was not expressed in normal colon mucosa. Strong positive staining for UCP2 with a diffuse distribution pattern was identified throughout the mucosa in colon cancer tissue samples with a positive expression rate of 85.9%. The UCP2 expression level was higher in colon cancer tissue samples at clinical stages III and IV than in those at stage I + II. Univariate analysis showed that the high UCP2 expression level was significantly correlated to colon cancer metastasis (hazard ratio = 4.321, confidence interval = 0.035-0.682, P = 0.046).


CONCLUSIONS
UCP2 is highly expressed in human colon cancer tissue and may be involved in colon cancer metastasis.
Department of Gastroenterology, First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu Province, China.
Xiao-Yi
XY
Kuai
Ze-Yu
ZY
Ji
Hong-Jie
HJ
Zhang
D000236:Adenoma / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China; D003110:Colonic Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D003111:Colonic Polyps / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D005260:Female; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000737:chemistry; D007473:Ion Channels / Q000032:analysis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D024101:Mitochondrial Proteins / Q000032:analysis* / Q000235:genetics; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071246:Uncoupling Protein 2; D015854:Up-Regulation
D007473:Ion Channels; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604389:UCP2 protein, human; D000071246:Uncoupling Protein 2