"⁹⁰Y-Labeled Anti-ROBO1 Monoclonal Antibody Exhibits Antitumor Activity against Small Cell Lung Cancer Xenograft"

Lung cancer has the highest incidence and mortality rates among all cancers. Small cell lung cancer (SCLC) constitutes approximately 15% of all lung cancer cases and exhibits a high growth rate and early metastases. When cancer is widespread in extensive stage, SCLC is highly malignant with no effective therapy established. Therefore, the development of more effective therapies is required for extensive-stage SCLC.

Professor Toshimitsu Momose, Project Research Associate Kentaro Fujiwara of the University of Tokyo Hospital, Professor Takao Hamakubo (Quantitative Biology and Medicine) and Professor Tatsuhiko Kodama (System Biology and Medicine) has developed a radiolabeled “tumor specific monoclonal antibody”. When administered in SCLC xenograft mice, the antibody exhibited an antitumor effect, killing tumor cells and markedly reducing tumor sizes.

This antibody is based on specifically recognizing a membrane protein, ROBO1, which is highly expressed in a SCLC cell (anti-ROBO1 antibody). It was labeled with Yttrium-90 (⁹⁰Y), a radioisotope used for treatment (⁹⁰Y-labelled anti-ROBO1 antibody). The resulting antibodies are used in “radioimmunotherapy,” a type of radiotherapy using radiolabeled tumor-specific monoclonal antibodies. The administered antibodies accumulate in tumor cells, exhibiting positive impacts in SCLC xenograft mice. The results of this study are expected to contribute to a complete cure and improvement in survival among patients with extensive-stage SCLC in the future.