As current molecular target drugs against malignant tumors, there have been developed and used, in practical clinic, many agents such as sorafenib used for liver cancer and renal cancer, cetuximab and bevacizumab used for large intestine cancer, erlotinib and gefitinib used for lung cancer, and trastuzumab used for breast cancer. As target substances of each agent, there can be exemplified cancer kinase, vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), HER2 protein, and the like. However, in relation to molecular target drugs against malignant tumors, there have also been reported skin disorder, gastrointestinal perforation, interstitial pneumonia, and deaths due to severe side effects such as liver failure. Therefore, appearance of a safer molecular target drug is desired. Meanwhile, although it is said that even healthy persons have thousands of malignant tumor (cancer) cells every day, everyone does not necessarily develop disease. It has been reported that incidence of liver cancer in autoimmune hepatitis (AIH) is about 0.7%/year (Aliment Pharmacol Ther 2006; 24:1197) and is obviously lower than 3%/year in chronic hepatitis C (Ann Intern Med 1999; 131:174).
It has been reported that a ribosomal protein RPL29 (Ribosomal protein L29) shows increased expression in cells of various malignant tumors such as large intestine cancer (Non Patent Literature 1), liver cancer (Non Patent Literature 2), gastric cancer (Non Patent Literature 3), thyroid cancer (Non Patent Literature 4) and breast cancer (Non Patent Literature 5). The RPL29 is a membrane protein expressed on a cell surface, and it has been reported that when the expression of the RPL29 is lowered, cells causing apoptosis are increased (Non Patent Literature 6), and cellular differentiation is induced (Non Patent Literature 1). In addition, it has been reported that a ribosomal protein RPS4X (Ribosomal protein S4, X-linked) shows increased expression in cells of various malignant tumors such as large intestine cancer (Non Patent Literature 7) and breast cancer (Non Patent Literature 8). However, it has not been reported that a substance targeting the ribosomal proteins RPL29 and RPS4X improved tumors.