Search for Crucial Molecules Involved in Acquisition of Cancer Aggressiveness through Establishment and Screening of Monoclonal Antibodies

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Hybridomas were produced using spleen cells from mice immunized with cell lysates extracted from highly aggressive human cancer cell lines or human tumor tissues fixed in methanol or stocked in liquid nitrogen. Hybridoma clones were selected on the basis of their immunohistochemical reactivities, such as those with tumor cells in areas of prominent tumor-stromal interaction, in various human cancers chosen from the accumulated files in our division. Thus monoclonal antibodies specifically recognizing functional molecules such as dysadherin, laminin 332 and tissue factor have been established. The molecules recognized by the hybridomas were actually expressed strongly at the invasive fronts of various cancers, and patients with overexpression of these molecules had a poor clinical outcome. Furthermore, a robotic technology-assisted tissue microarray system was established for mass-screening of monoclonal antibodies using sections of human cancer tissue (Fig.). We are now attempting high-throughput establishment of monoclonal antibodies recognizing crucial molecules involved in acquisition of cancer aggressiveness. The monoclonal antibodies that we hope to obtain in this way will greatly contribute to the diagnosis of cancers and estimation of tumor aggressiveness and patient prognosis when they are used for immunohistochemical and immunocytochemical examination of clinical samples.

Fig. Tissue microarray system developed for high-throughput screening of monoclonal antibodies.