By the iTRAQ quantitative proteomics analysis on ovarian cancer cell lines, we identified LSR as a tumor antigen of epithelial ovarian cancers in humans (Hiramatsu et al., Cancer Res, 2017). Patients with high-LSR ovarian cancer showed significantly poor survival than those with low-LSR cancer. As was reported previously in normal cells, LSR (+) tumor cells could uptake lipoprotein via LSR and this was inhibited in vitro by our anti-LSR monoclonal antibody. Moreover, anti-LSR antibody successfully inhibited growth of patient-derived ovarian cancer xenografted in immuno-deficient mice. These findings highlight LSR as a key lipoprotein receptor that regulates lipid metabolism in tumors. Whereas our anti-LSR antibody can recognize both human and mouse LSR, this antibody showed no severe adverse effects on normal mouse tissues. We thus believe that our antibody is applicable to treat LSR(+) human cancers in the future.