e15084 Background: Cetuximab is a monoclonal antibody that specifically blocks the EGFR. We follow -up study the efficacy and toxicity of cetuximab with chemotherapy in the treatment of advanced colorectal cancer from Chinese in East China. Methods: We analyzed tumor samples from 120 patients with advanced colorectal cancer by direct sequencing, to observe the mutations status in exon 2,3 of K-ras gene. And 30 patients were followed up according the RECIST standard for their treatment outcome of cetuximab plus chemotherapy at 2 -12 months. Results: K-ras mutations were identified in 48 of 120(40%) patients with colorectal cancer in exon2, which including 8 mutation types; 38/48(79.2%) mutations in 12 codon(G12D 43.7%,G12V 25%,G12C 10.4%,G12R 6%,G12S 4%,G12A 2%) and 10/48(18.7%) in 13 codon(G13D 18.7%,G13C 2%). None mutation was found in 61codon of exon3. we observed the clinical efficacy of 30 patients treated by cetuximab plus chemotherapy, of 21 patients with wild-type K-ras tumors as compared with 9 patients with mutated K-ras significantly improved the response rate (5/21 21.8% vs 1/9 11.1%,P<0.01)and the disease control rate (19/21 90.4% vs,2/9 22.2%,P<0.01). There were a few patients with mutated K-ras tumors benefit from cetuximab, in which the fluorescence intensity of mutation cells of all detected tumor tissue approach to 1:3 status by sequencing analysis. The major toxicities of treatment were acne-like rash, which were found in 14/21(66.6%)of patients with wild-type K- ras, and 5/9(55.5%)of patients with mutated K-ras . Conclusions: The East-China patients share the same (40%) mutation frequency and type of k-ras gene with other races . Patients with wild type K-ras mutation have significantly higher Response rate and disease control rate on cetuximab plus chemotherapy treatment .Our results once again show that somatic mutations status of k-ras is a major determinant of cetuximab response in advanced colorectal cancer. There was no statistical correlation between acne-like rash of the major toxicities and mutations status of k-ras. There were a few patients bearing mutated k-ras did benefit from cetuximab, that would need to be validation between Chinese or Ethnicity association phenotype by a large numbers of samples. No significant financial relationships to disclose.
Adverse Adipose Phenotype and Hyperinsulinemia in Gravid Mice Deficient in Placental Growth Factor
