TP53 and neoplasm: ,20 We have further developed OBP-702 as a modification of OBP-301 that expresses the wild-type p53 gene, so OBP-702 can suppress the viability of various types of tumor cells more efficiently compared with OBP-301 via exogenous p53 overexpression in tumor cells.21, 22, 23 The i.p. administration of antitumor agents is advantageous for peritoneal metastasis compared with systemic therapy, because these agents can reach the peritoneal cavity directly in high concentrations.24