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Objective: To explore the relationship between KRAS gene status and efficacy of Cetuximab (C225) combined with chemotherapy on advanced colorectal cancer in Chinese patients, and to evaluate the safety of C225., Methods: From May 2006 to March 2009, 81 patients with advanced colorectal cancer received Cetuximab combined with chemotherapy were enrolled in this study. The rate of KRAS mutation and the relationship of KRAS with response rate (RR), progression-free survivor (PFS), overall survival (OS) and adverse reaction of C225 were analyzed retrospectively., Results: All the 81 patients received C225 therapy, and the overall RR was 33.3%. The RR of initiate therapy was 57.1%; of the second line and over the third line therapy was 38.5% and 22.0% respectively. KRAS gene phenotype examination was performed in 44 patients whose tumor samples were available. KRAS mutation was found in 20 cases (45%). Out of 44 patients, 43 were evaluable for response. RR was 5% and 43.48% in KRAS mutation and wild KRAS patients respectively (P =0.002). The median PFS was 7.0 weeks and 18.6 weeks in mutational KRAS patients and wild KRAS patients, reaching statistical significance (P =0.003). The median OS was 15.2 months and 17.3 months in mutational KRAS patients and wild KRAS patients respectively without statistical significance (P =0.463). The common adverse reactions were leucopenia, nausea, vomiting and rash. All the adverse reactions were tolerated. The incidence of skin rash in patients with mutational KRAS and patients without KRAS mutation was 40% and 42% respectively, without statistical significance (P =0.91)., Conclusion: C225 combined with chemotherapy is well-tolerated in Chinese patients with advanced colorectal cancer, and it can significantly prolong PFS of patients with wild KRAS as compared to patients with KRAS mutation.

Background & Objective: CY-B12, a new dibenzon-xanthene, has been synthesized recently. This study was to investigate the in vitro antiproliferative activity of CY-B12 and its possible mechanisms., Methods: The inhibitory effects of CY-B12 on proliferation of gastric carcinoma cell line MGC803, nasopharyngeal carcinoma cell line CNE-2, oral epithelial carcinoma cell line KB-3-1, and lung cancer cell line Glc82 were assessed by MTT assay. Cell cycle distribution and apoptosis were detected by flow cytometry (FCM). Apoptotic morphology of CNE-2 cells was observed under fluorescent microscope after Hoechst33258 staining. The expression of cell cycle-related proteins Cdc25C, Cdc2, and Cyclin B1 were measured by Western blot. DNA damage was detected by single cell gel electrophoresis (SCGE)., Results: CY-B12 obviously inhibited the proliferation of MGC803, CNE-2, KB-3-1, and Glc82 cells; the IC(50) values were 7.51, 9.58, 8.84, and 15.99 micromol/L, respectively. After treatment of CY-B12, CNE-2 cells were arrested at G(2)/M phase; chromatin condensation, apoptotic bodies, and sub-G1 peak were observed in CNE-2 cells. The protein expression of Cdc25C in CNE-2 cells was down-regulated by CY-B12 in a dose-dependent mannerû whereas Cyclin B1 and Cdc2 were up-regulated by low dose of CY-B12, and down-regulated by high dose of CY-B12. CY-B12 induced DNA damage in CNE-2 cells in a dose-dependent manner., Conclusion: CY-B12 has potent in vitro antiproliferative activity, which may be exerted through breaking DNA, down-regulating cell cycle-related protein Cdc25C, and inducing cell cycle arrest and apoptosis.