IMP3 is a novel prognostic marker that correlates with colon cancer progression and pathogenesis.
BACKGROUND
Insulin-like growth factor-II mRNA-binding protein 3 (IMP3) plays a vital role in carcinogenesis; however, its significance and prognostic value in colon cancer remain unclear.


METHODS
In this study, a tissue microarray (TMA) containing 203 samples of primary colon cancer was assessed for IMP3 expression by immunohistochemistry. The TMA included 66 lymph node metastasis (LNM) samples. The mRNA and protein expression levels of IMP3 were evaluated by reverse transcription-PCR and Western blot analysis, respectively.


RESULTS
Cytoplasmic immunoreactivity of IMP3 was significantly higher in LNM (93%) than in primary colon cancer (65%) or normal mucosa (3.9%). Increased IMP3 levels were significantly correlated with higher clinical stage, T classification, LNM, presence of distant metastasis, and Ki-67 positivity. IMP3 was up-regulated in colon cancer compared with paired normal colonic mucosa. IMP3 expression was associated with an 11-fold increased risk of distant metastases (hazard ratio (HR) 10.7; 95% confidence interval (CI) 3.3-34.5; P < 0.0001). Patients with IMP3-positive localized tumors had lower 5-year disease-free survival (DFS) (HR 2.87; 95% CI 1.65-4.98; P < 0.0001) and overall survival (OS) (HR 4.2; 95% CI 2.51-10.17; P < 0.0001) than those with IMP3-negative tumors. Multivariate survival analysis showed that IMP3 was an independent prognostic marker for DFS (HR 1.92; 95% CI 1.06-3.47; P = 0.03) and OS (HR 2.37; 95% CI 1.2-4.7; P = 0.014).


CONCLUSIONS
IMP3 may play an important role in colon cancer progression and could serve as a prognostic biomarker to identify patients at risk of developing metastasis or recurrence after colonectomy.
Li
Dawei
D
Department of General Surgery, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, People's Republic of China.
Yan
Dongwang
D
Tang
Huamei
H
Zhou
Chongzhi
C
Fan
Junwei
J
Li
Shuxia
S
Wang
Xiaoliang
X
Xia
Jun
J
Huang
Fei
F
Qiu
Guoqiang
G
Peng
Zhihai
Z
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D003106:Colon / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009364:Neoplasm Recurrence, Local / Q000378:metabolism* / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D046888:Tissue Array Analysis; D055815:Young Adult
D014408:Biomarkers, Tumor; C498780:IGF2BP3 protein, human; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins