Published in Cancer Detection and Prevention 1997; 21(4):346-354.

Analysis of Specific Accumulation of Radiolabeled Anti-Carcinoembryonic Antigen Monoclonal Antibody Cea1o2 in Colorectal Cancer Using Computed Radiography

Tadashi Watanabe MDa, Tsuyoshi Satohb, Masanori Tadokoroc, Junichi Sakamotod, Hiroki Murayamae. Katsuki Itob, Sadayuki Sakumac, Hiroshi Takagib

aFujita Health University Nanakuri Sanatorium, Hisai, Mie, Japan; bDepartment of Surgery II, Nagoya University School of Medicine, Nagoya, Japan; cDepartment of Radiology, Nagoya University School of Medicine, Nagoya, Japan; dDepartment of Gastroenterological Surgery, Aichi Cancer Center, Nagoya, Japan; eDepartment of Surgery, Nagoya National Hospital, Nagoya, Japan

Address all correspondence and reprint requests to: Tadashi Watanabe, MD, Fujita Health University, Nanakuri Sanatorium, 424-1 Mukaihiro, Otori, Hisai, Mie 514-12, Japan.

ABSTRACT: The specific accumulation of radiolabeled anti-carcioembryonic antigen (CEA) monoclonal antibody (MoAb) CEA1O2 in colorectal cancers was investigated by autoradiography of surgical specimens using Fuji Computed Radiography (FCR). Five patients with colorectal cancer were injected intravenously with [131 I]-labeled intact CEA1O2 or its F(ab')2. Primary tumor and liver metastases were successfully detected by external scanning with gamma camera in four cases. Autoradiographic study using FCR showed predominant localization of [131 I]-labeled CEA1O2 in primary tumors and liver metastases in all cases. Even the small-sized liver metastasis (0.5 cm) was clearly visualized. The pixel distribution curves showed the heterogeneity of the distribution of administered MoAb in the tumors. In the quantitative distribution analysis of CEA1O2, the uptake of the primary tumor was 10-fold greater than that of the normal colon mucosa. These results suggest that MoAb has great potential in radioimmunodetection as well as possible use in antibody-directed therapy.

KEY WORDS: anti-carcinoembryonic antigen monoclonal antibody, autoradiography, colorectal cancer, radioimmunodetection.