The density of macrophages in the invasive front is inversely correlated to liver metastasis in colon cancer.
BACKGROUND
Although an abundance of evidence has indicated that tumor-associated macrophages (TAMs) are associated with a favorable prognosis in patients with colon cancer, it is still unknown how TAMs exert a protective effect. This study examined whether TAMs are involved in hepatic metastasis of colon cancer.


METHODS
One hundred and sixty cases of pathologically-confirmed specimens were obtained from colon carcinoma patients with TNM stage IIIB and IV between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. The density of macrophages in the invasive front (CD68TFHotspot) was scored with an immunohistochemical assay. The relationship between the CD68TFHotspot and the clinicopathologic parameters, the potential of hepatic metastasis, and the 5-year survival rate were analyzed.


RESULTS
TAMs were associated with the incidence of hepatic metastasis and the 5-year survival rate in patients with colon cancers. Both univariate and multivariate analyses revealed that the CD68TFHotspot was independently prognostic of survival. A higher 5-year survival rate among patients with stage IIIB after radical resection occurred in patients with a higher macrophage infiltration in the invasive front (81.0%) than in those with a lower macrophage infiltration (48.6%). Most importantly, the CD68TFHotspot was associated with both the potential of hepatic metastasis and the interval between colon resection and the occurrence of hepatic metastasis.


CONCLUSIONS
This study showed evidence that TAMs infiltrated in the invasive front are associated with improvement in both hepatic metastasis and overall survival in colon cancer, implying that TAMs have protective potential in colon cancers and might serve as a novel therapeutic target.
State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, 651 Dongfeng R E, 510060, Guangzhou, China.
Qiang
Q
Zhou
Rui-Qing
RQ
Peng
Xiao-Jun
XJ
Wu
Qing
Q
Xia
Jing-Hui
JH
Hou
Ya
Y
Ding
Qi-Ming
QM
Zhou
Xing
X
Zhang
Zhi-Zhong
ZZ
Pang
De-Sen
DS
Wan
Yi-Xin
YX
Zeng
Xiao-Shi
XS
Zhang
D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000556:secondary; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D015996:Survival Rate; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D014408:Biomarkers, Tumor; C067980:CD68 antigen, human; D000097382:CD68 Molecule