In vivo molecular imaging of gastric cancer by targeting MG7 antigen with confocal laser endomicroscopy.
OBJECTIVE
In vivo molecular imaging represents a powerful tool for the immediate diagnosis of gastric cancer. In this study, the monoclonal antibody MG7, which is a specific molecular marker against gastric cancer, was labeled with fluorescent agents to enable in vivo real-time imaging by confocal laser endomicroscopy (CLE).


METHODS
In vivo molecular imaging was performed in tumor-bearing mice from two kinds of human gastric cancer cell lines. Xenograft tumors were visualized in vivo first with a whole-body fluorescent imaging device and then by CLE using fluorescently labeled MG7 antibody. Gastric cancerous tissue and noncancerous mucosa from human biopsies or surgical specimens were also examined ex vivo by CLE.


RESULTS
Intravital imaging of xenograft tumors revealed a specific cellular signal, whereas no specific signal was observed in control tissue or in mice injected with irrelevant antibodies. An ex vivo experiment on human specimens using a rigid confocal probe showed positive fluorescent staining in 22/23 samples diagnosed as gastric cancer and weak signals in 5/23 noncancerous tissue samples. CLE evaluation correlated well with immunohistochemical findings.


CONCLUSIONS
Screening tumors in vivo by CLE may help to detect MG7-Ag-positive tissues, decrease the sampling error by screening the large tumor surface not routinely screened by biopsy or conventional immunohistochemistry, and facilitate early detection of gastric carcinoma.
Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, China.
Z
Z
Li
X L
XL
Zuo
C Q
CQ
Li
C J
CJ
Zhou
J
J
Liu
M
M
Goetz
R
R
Kiesslich
K C
KC
Wu
D M
DM
Fan
Y Q
YQ
Li
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology*; D002277:Carcinoma / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D057054:Molecular Imaging; D016037:Single-Blind Method; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; C508753:MG7 antigen, human