Spherical fluorinated covalent organic polymer for highly efficient and selective extraction of fipronil and its metabolites in soil.

Covalent organic polymers (COPs) have garnered considerable attention as promising adsorbents of online solid phase extraction (online SPE). Morphology modulation provides an appealing solution to enhance adsorption efficiency and reduce back-pressure in the absorbent. However, the synthesis of COPs with regular geometric shapes and specific adsorption selectivity remains challenging. In this study, a uniform spherical fluorinated COP (F-sCOP, average diameter: 2.14 µm) was successfully synthesized by Schiff base reaction of 1,3,5-triformylphoroglucinol (TP) and 2,2'-bis(trifluoromethyl)benzidine (TFMB). The F-sCOP had a large surface area (BET: 346.2 m2 g-1), remarkable enrichment capacity (enrichment factors: 186-782), high selectivity toward fipronil and its metabolites (adsorption efficiency >93.1%), and admirable service life (>60 times). Based on the adsorbent, a novel µ-matrix cartridge extraction-online-µ-solid phase extraction-high performance liquid chromatography-mass spectrometry (µ-MCE-online-µ-SPE-HPLC-MS) method was constructed and used to track trace fipronil and its metabolites in soil. The proposed method exhibited a wide linear range (0.05-1000 ng g-1), low quantitation limits (LOQs: 0.0027-0.011 ng g-1), high recoveries (90.1-119.6%) and good repeatability (RSD ≤10.5%, n = 3) for fipronil analysis. This study paves the way for pesticide analysis in soil risk assessment.

Construction of continuous flow catalytic reactor-HPLC system with ultrahigh catalytic activity using 2D nanoflower MOF-derived Cu2O/Cu/PDA/CF catalyst.

Currently, metal-organic frameworks (MOFs) derived materials have been widely concerned for the reduction of 4-nitrophenol (4-NP). However, complex recovery of powder catalysts and low utilization ratio of active sites make their application challenging. Herein, a novel Cu2O/Cu/PDA/CF catalyst has been developed for the rapid reduction of 4-NP to 4-aminophenol (4-AP). The catalyst was constructed by compositing a two-dimensional nanoflower MOF-derived nanoporous Cu2O/Cu network on a polydopamine (PDA)-modified porous copper foam by a mild and controllable in-situ reduction synthesis. Notably, an enhanced catalytic performance of Cu2O/Cu/PDA/CF was obtained for 4-NP reduction with a rate constant (k) of 0.8001 min-1, outperforming Cu/PDA/CF-X (X = 400, 500 and 600 â„ƒ pyrolysis temperature) catalysts (2.3-6.4 folds), and even many reported catalysts (2.3-46.5 folds). The ultrafast degradation of 4-NP was completed in 70 s. Moreover, an ingenious online continuous flow catalytic reactor (CFCR)-high performance liquid chromatography (HPLC) system was constructed for automatic and real-time monitoring of the reduction reaction. System stability experiments over 300 min revealed a surprisingly high reaction k value of 76.68 min-1 at low NaBH4 usage, significant increasing by 2-3 orders of magnitude compared with Cu2O/Cu/PDA/CF batch catalysis, due to the high aspect ratio of 2D nanoflower MOF and convection-accelerated mass transfer. This work offers new insights for the rational design of catalytic reactor and its potential application in wastewater treatment.

Tunable Fluorine-Functionalized Scholl-Coupled Microporous Polymer for the Selective Adsorption and Ultrasensitive Analysis of Environmental Liquid-Crystal Monomers.

Liquid-crystal monomers (LCMs), especially fluorinated biphenyls and analogues (FBAs), are identified to be an emerging generation of persistent organic pollutants. However, there is a dearth of information about their occurrence and distribution in environmental water and lacustrine soil samples. Herein, a series of fluorine-functionalized Scholl-coupled microporous polymers (FSMP-X, X = 1-3) were designed and synthesized for the highly efficient and selective enrichment of FABs. Their hydrophobicity, porosity, chemical stability, and adsorption performance (capacity, rate, and selectivity) were regulated preciously. The best-performing material (FSMP-2) was employed as the on-line fluorous solid-phase extraction (on-line FSPE) adsorbent owing to its high adsorption capacity (313.68 mg g-1), fast adsorption rate (1.05 g h-1), and specific selectivity for FBAs. Notably, an enrichment factor of up to 590.2 was obtained for FSMP-2, outperforming commercial C18 (12.6-fold). Also, the underlying adsorption mechanism was uncovered by density functional theory calculations and experiments. Based on this, a novel and automated on-line FSPE-high-performance liquid chromatography method was developed for ultrasensitive (detection limits: 0.0004-0.0150 ng mL-1) and low matrix effect (73.79-113.3%) determination of LCMs in lake water and lacustrine soils. This study offers new insight into the highly selective quantification of LCMs and the first evidence for their occurrence and distribution in these environmental samples.

Evaluation of Clinical Diagnostic and Prognostic Value of Preoperative Serum Carcinoembryonic Antigen, CA19-9, and CA24-2 for Colorectal Cancer.

Objective: To investigate the clinical diagnostic and prognostic value of preoperative serum tumor markers in patients with colorectal cancer (CRC). Methods: From September 2013 to September 2016, we enrolled 980 patients diagnosed with CRC and 870 healthy subjects from The Affiliated Cancer Hospital of Shanxi Medical University. Patients were grouped and compared in accordance with tumor stage, tumor location, lymph node metastasis, distant metastasis, histological type, depth of invasion, growth type, and other factors. Serum carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and carbohydrate antigen 24-2 (CA24-2) concentrations in patient peripheral blood were measured, and the diagnostic value of the tumor markers in diagnosing CRC was assessed by receiver operating characteristic analysis. Results: The sensitivity of serum tumor markers in combination was significantly higher than serum tumor markers detected individually. CA19-9 levels were significantly correlated with CA24-2 levels (r = 0.884; P < .001) in patients with CRC. The preoperative CEA, CA19-9, and CA24-2 levels in patients with colon cancer were significantly higher than in patients with rectum cancer (all P < .001). The CA19-9 and CA24-2 levels were significantly higher in patients with lymph node metastasis than without (both P < .001). In addition, the CEA, CA19-9, and CA24-2 levels in patients with distant metastasis were significantly higher than those in patients without metastasis (all P < .001). Stratified analysis showed that CEA, CA19-9, and CA24-2 levels were significantly correlated with TNM staging (P < .05). With regard to the depth of tumor invasion, CEA, CA19-9, and CA24-2 levels in tumors outside the serosa were significantly higher than those in other tumor types (P < .05). In terms of diagnostic performance, CEA had a sensitivity of 0.52 and a specificity of 0.98, CA19-9 had a sensitivity of 0.35 and a specificity of 0.91, and CA24-2 had a sensitivity of 0.46 and a specificity of 0.95. Conclusion: The detection of serum tumor markers CEA, CA19-9, and CA24-2 is a good method for supporting diagnosis, making treatment decisions, judging therapeutic effect, and predicting prognosis when managing patients with CRC.

Leptin and leptin receptor expression as biomarkers for breast cancer: a retrospective study.

BACKGROUND: Effective screening and treatment have reduced the number of women dying from breast cancer (BC). However, the long-term sequelae of BC treatment and psychosocial factors seriously affect the life quality of BC patients and survivors. Therefore, the discovery and application of targeted biomarkers to improve the functional outcome and life quality of BC patients is necessary. AIMS: To explore the impact of leptin (LEP)/ leptin receptor (LEPR) expression on occurrence and survival of BC. METHODS: Totally 132 primary BC and 66 non-BC patients who underwent surgery in department of breast surgery in Shanxi Cancer Hospital from January to October in 2009 were enrolled in this retrospective study. LEP and LEPR were examined in BC tissues, benign breast tissues, para-carcinoma tissues using immunohistochemical staining. Kaplan-Meier curve was generated to test survival time. RESULTS: The high level expression of LEP and LEPR in BC tissues were significantly higher than that in benign breast tissues and in para-carcinoma tissues (all P < 0.05). The LEP expression in patients with lymph node metastases was significantly higher than that in patients without lymph nodes metastases (P = 0.002). LEPR expression was correlated with higher Ki-67 rate (P = 0.002). LEP and LEPR both had no impact on survival (all P > 0.05). CONCLUSIONS: High LEP/LEPR expression were risk factors for occurrence of BC, but without impact on survival.

Micro-matrix cartridge extraction followed by online micro-solid phase extraction based on polystyrene@hydroxypropyl-ß-cyclodextrin nanofibers for selective determination of fipronil and its metabolites in soil.

Micro-matrix cartridge extraction coupled on-line to micro-solid phase extraction-high performance liquid chromatography-mass spectrometry (µ-MCE-online-µ-SPE-HPLC-MS) is presented. Micro-matrix cartridge extraction (µ-MCE) was applied to highly efficient desorption of adsorbed pesticides from contaminated soil with favorable extraction efficiency (100%). Novel polystyrene@hydroxypropyl-ß-cyclodextrin (PS@HPCD) electrospun nanofibers with 3D network structure were prepared to selectively capture fipronil and its metabolites. High selectivity was obtained with adsorption efficiency ≥ 86.64% via complexation, hydrophobic affinity, and π-π interactions. PS@HPCD nanofibers exhibited remarkable advantages such as excellent enrichment factors (24-55), superior permeability, and long service life (> 65 times). Under the optimum conditions, wide linear range (0.1-1000 ng g-1), low detection limits (0.0032-0.0067 ng g-1), high recoveries (84-124.5%), favorable repeatability (RSD ≤ 10.4%, n = 5), and reproducibility (RSD ≤ 7.2%, n = 3) were acquired for fipronil and three metabolites. The developed method was applied to the pesticide determination in actual soils and the ISO-certified soil with satisfactory recoveries (96.5%). The method developed provides a green, efficient, and miniaturized method for the determination of trace pesticide residues in soil.

Designing Hierarchically Porous Single Atoms of Fe-N5 Catalytic Sites with High Oxidase-like Activity for Sensitive Detection of Organophosphorus Pesticides.

Recently, single-atom catalysts (SACs) have been used to construct biosensors for the determination of organophosphorus pesticides (OPs). However, most nanozymes including SACs are peroxidase-like enzymes and require highly toxic and unstable hydrogen peroxide (H2O2) as a co-reactant to generate reactive oxygen species. Inspired by the heme site of cytochrome c oxidases (Ccos), the construction of Fe-N5-coordinated SACs by introducing axial N ligands is expected to bind O2 to generate active metal-oxygen intermediates. Herein, a SAC with an Fe-N5 active center confined by hierarchically porous carbon nanoframes (Fe SAs/N5-pC-4) was prepared by a polymerization-pyrolysis-evaporation-etching strategy, and its underlying enzyme-like mechanism was uncovered through experiments and density functional theory calculations. The 100% metal atom utilization, increased accessible active sites, accelerated mass transfer, excellent hydrophilicity, and an electron-driven mechanism of axial N endow the SAC with enhanced oxidase-like activity. Notably, its catalytic rate constant (0.398 s-1) is 569 times greater than that of the commercial Pt/C catalyst. Similar to the catalytic mechanism of Ccos, O2 can be converted into reactive oxygen species, avoiding the use of co-reactant H2O2 effectively. In addition, based on the inhibitory effect of thiols on the active site of Fe SAs/N5-pC-4, a biosensor was constructed and applied to the colorimetric analysis of OPs. This provides a facile, cost-effective method for efficient OP screening at sites to help control their contamination.

Boronic Acid-Functionalized Scholl-Coupling Mesoporous Polymers for Online Solid-Phase Extraction of Brassinosteroids from Plant-Derived Foodstuffs.

Brassinosteroids (BRs) are natural, nontoxic, non-hazardous, biosafe, and eco-friendly plant hormones, possessing diverse pharmacological activities. However, little is known about the type and content of BRs in frequently consumed plant-derived foodstuffs because of their low abundance and high abundance of interference. In this study, a selective, accurate, and sensitive method based on the online solid-phase extraction using the boronic acid-functionalized Scholl-coupling microporous polymer was developed for the analysis of BRs in plant-derived foodstuffs. Under optimum conditions, an excellent linearity (R2 ≥ 0.9970) and lower limits of detection (0.010-0.070 pg mL-1) were obtained. The high relative recoveries were in the range of 90.33-109.34% with relative standard deviations less than 9.73%. The method was successfully used for the determination of BRs in fifteen plant-derived foodstuffs. The present work offers a valuable tool for exploring BRs from the plant-derived foodstuffs and can provide useful information for developing functional foods.

Molecularly imprinted polymers prepared from a single cross-linking functional monomer for solid-phase microextraction of estrogens from milk.

In this work, a single cross-linking functional monomer, 2,5-divinylterephthalaldehyde, was designed and synthesized to simplify the preparation of molecularly imprinted polymers (MIPs). In the presence of estradiol as a template, MIPs were successfully prepared using 2,5-divinylterephthalaldehyde along with a solvent and initiator. This method reduced most of the complex variables encountered in the traditional synthesis. Characterization of the morphology and structure of the MIPs was performed by scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. Compared with non-imprinted polymers, the MIPs had higher adsorption capacities for five estrogens with imprinting factors above 2.9. The MIPs had high extraction efficiencies, good functional properties, long lifetimes, and good reproducibility, which made them suitable for solid-phase microextraction (SPME). Coupled with ultra-high performance liquid chromatography tandem mass spectrometry, the MIP-based fibers were applied to SPME for the analysis of five estrogens in milk samples. Under the best conditions, the established method had a wide linear range (0.5-10000 ng kg-1), low limits of detection (0.08-0.26 ng kg-1) and quantification (0.26-0.87 ng kg-1), good precision (3.2-8.1%, n = 6), and fiber-to-fiber reproducibility (4.3%-8.8%, n = 3). The MIPs-based fibers can be reused at least 60 times without apparent loss of extraction efficiency. Finally, this method was applied to the determination of target estrogens in milk samples with satisfactory relative recoveries (84.3%-105%, relative standard deviation ≤ 7.8%).

Facile synthesis of trifluoromethyl covalent organic framework for the efficient microextraction of per-and polyfluorinated alkyl substances from milk products.

Trifluoromethyl covalent organic framework (CF3-COF) is facilely synthesized at room temperature using for solid-phase microextraction (SPME). The CF3-COF coating displays an improved extraction performance for per- and polyfluorinated alkyl substances (PFASs) comparing to amorphous polymer coating, non-contained fluorine covalent organic framework coating and commercially available SPME coating. The fluorine affinity of trifluoromethyl in CF3-COF for PFASs is demonstrated using the density functional theory calculation. Following the microextraction with CF3-COF-coated fiber, the targeted PFASs are eluted with 1 mL acetonitrile and quantified by ultrahigh performance liquid chromatography tandem mass spectrometry. The low limits of detection are 0.1-0.7 pg g-1 for milk and 0.2-0.8 pg g-1 for milk powder, suggesting the outstanding sensitivity. The precision for the method ranges between 2.9 and 9.9%. The fiber-to-fiber repeatability is in the range of 4.2-9.5%. Under the optimum conditions, the relative recoveries are 91.0-110% with RSDs ≤ 10% for milk and 89.8-111% with RSDs ≤ 10% for milk powder.

Amino-modified Scholl-coupling mesoporous polymer for online solid-phase extraction of plant growth regulators from bean sprouts.

A new amino-modified Scholl-coupling mesoporous polymer (NH2@SMPA)-online solid-phase extraction method, coupled with high-performance liquid chromatography (online SPE-HPLC) was established for the analysis of six plant growth regulators (PGRs) in bean sprouts. NH2@SMPA was synthesized by acid-catalyzed deacetylation of acetylamino-Scholl-coupling mesoporous polymer (SMPA). The diversity of functional groups, such as aromatic, acetylamino, and NH2, was conducive to multiple binding interactions between NH2@SMPA and PGRs. NH2@SMPA exhibited superior extraction capability for PGRs, compared with SMPA and commercial adsorbents. The extraction conditions, including loading solvent, pH of loading solution, eluting solvent, and flow rates of loading and elution, were optimized. Under the optimized conditions, wide linear ranges (0.01-500 µg kg-1) and low detection limits (2.34-20.2 ng kg-1) were obtained. The recoveries were satisfactory, i.e., 86.0% to 109% with relative standard deviations ≤9.8% (n = 3). Finally, the online SPE-HPLC method was successfully used for determination of PGRs in bean sprouts.

Covalent Organic Framework as a Heterogeneous Ligand for the Regioselective Oxidative Heck Reaction.

A simple imine-based covalent organic framework (COF) as heterogeneous ligand for PdII-promoted Heck reaction is reported. Good regioselectivity for a wide range of electronically unbiased olefins is obtained (linear/branched >100:1 in most cases). Related tests and density functional theory calculations are used to explore the reason underlying the high selectivity. This research opens a route for COF as an intriguing platform to control regioselectivity catalysis.

[Relationship of c-kit and platelet-derived growth factor receptor alpha gene mutation features with prognosis of patients with gastrointestinal stromal tumor].

OBJECTIVE: To explore the relationship between c-kit and platelet-derived growth factor receptor alpha(PDGFRA) gene mutation features and the prognosis of gastrointestinal stromal tumor(GIST). METHODS: Clinicopathological, genetic testing and follow-up informations of patients admitted to the Shanxi Tumor Hospital from June 2000 to January 2009 were collected. The survival was calculated and univariate analysis was conducted using the Kaplan-Meier method. Multivariate analysis was conducted by the Cox regression method. RESULTS: The 5-year disease-free survival rate was 61.5% and the 5-year overall survival rate was 67.4%. The 5-year disease-free survival rates of patients without disease among those with c-kit exon 11 mutation (n=77), c-kit exon 9 mutation(n=4), and PDGFRA exon 18 mutation (n=2) were 63.4%, 14.3% and 100%, and the 5-year overall survival rates were 70.8%, 50.0% and 100%, respectively. In the patients with c-kit exon 11 mutation, the 5-year disease-free survival rates among those with point mutations(n=26), deletion mutations(n=44), and duplication mutations(n=7) were 87.1%, 44.9% and 80.0%, and the 5-year overall survival rates were 88.1%, 57.0% and 100%, respectively. There were significant differences in overall survival among different factors. Multivariate analysis showed that gene mutation was not the independent factor of prognosis(P=0.492). CONCLUSIONS: In GIST patients undergoing surgery without imatinib treatment, mutated genotype is better than wild type in terms of prognosis. Gene mutation is not the independent factor of prognosis in GIST patients.

Effectiveness and safety of laparoscopic resection versus open surgery in patients with rectal cancer: a randomized, controlled trial from China.

BACKGROUND: The long-term survival and safety of laparoscopic surgery in patients with rectal cancer remain unclear. The aim of this trial was to assess the efficacy and safety of laparoscopic surgery for treatment of rectal cancer. METHODS: We undertook a randomized, controlled trial in 343 patients with rectal cancer between May 2004 and April 2008. One hundred sixty-nine patients were randomly assigned to laparoscopic surgery and 174 patients to open surgery. The main endpoint was 3-year survival. Data were analyzed according to the intention-to-treat principle. RESULTS: Laparoscopic surgery was associated with earlier recovery of bowel movement compared with open surgery. The average time to first discharge, bowel movement, resumption of fluid intake, and activity out of bed in laparoscopic surgery were shorter by 0.63, 0.32, 0.33, and 0.63 day, respectively (P < .001). The incidences of postoperative morbidities such as infectious complications, anastomotic leakage, anastomotic stenosis, and deep vein thrombosis have no differences. No differences were found in the comparison of long-term survival. INTERPRETATION: Laparoscopic surgery for rectal cancer is as safe and effective as open surgery in terms of oncology outcomes. Long-term survival for patients with rectal cancer undergoing laparoscopic surgery were similar to those undergoing conventional open surgery, thus supporting the continued use of laparoscopic surgery in Chinese patients with rectal cancer.

Irinotecan or oxaliplatin combined with 5-fluorouracil and leucovorin as first-line therapy for advanced colorectal cancer: a meta-analysis.

BACKGROUND: To compare clinical efficacy and toxicity of irinotecan combined with 5-fluorouracil and leucovorin with those of oxaliplatin combined with 5-fluorouracil and leucovorin as first-line therapy for advanced colorectal cancer. METHODS: Literature search was performed by keywords "irinotecan", "oxaliplatin" and "colorectal cancer" on all randomized controlled trails reported on irinotecan versus oxaliplatin combined with 5-fluorouracil and leucovorin as first-line therapy for advanced colorectal cancer in MEDLINE, OVID, Springer, Cochrane Controlled Trials Register (CCTR) and CBMdisc (Chinese Biology and Medicine disc) before January 2010. Two authors drew the details of trial design, characteristics of patients, outcomes, and toxicity from the studies included. Data analysis was performed by RevMan 4.2. RESULTS: According to the screening criteria, 7 clinical studies with 2095 participants of advanced colorectal cancer were included in this meta analysis. The baseline characteristics of irinotecan group were similar to those of oxaliplatin group. The response rate of oxaliplatin group was higher than that of irinotecan group (relative risk (RR) = 0.82, 95% confidence interval (95%CI) (0.70, 0.96), P = 0.01), and the median overall survival of oxaliplatin group was longer by 2.04 months than that of irinotecan group (95%CI (-3.54, -0.54), P = 0.008). In the comparison of grade 3 - 4 toxicity between the two groups, the incidences of nausea, emesis, diarrhoea and alopecia in irinotecan group were higher than those in oxaliplatin group (RR = 1.94, 95%CI (1.22, 3.09), P = 0.005; 1.71, 95%CI (1.34, 2.18), P < 0.001; 14.56, 95%CI (4.11, 51.66), P < 0.0001), respectively. However, the incidence of neurotoxicity, neutropenia and thrombocytopenia in irinotecan group were lower than those in oxaliplatin group (RR = 0.06, 95%CI (0.03, 0.14), P < 0.00001; 0.70, 95%CI (0.55, 0.91), P = 0.006; 0.18, 95%CI (0.05, 0.61), P = 0.006), respectively. CONCLUSIONS: Both irinotecan and oxaliplatin combined with 5-fluorouracil and leucovorin were effective in the first-line therapy of advanced colorectal cancer. However, the combined regimen of oxaliplatin plus 5-fluorouracil and leucovorin is more excellent. Irinotecan tended to result in more gastrointestinal tract reactions than oxaliplatin did, but the myelosuppression and neurotoxicity were more frequent in oxaliplatin regimen than irinotecan regimen.

[Efficacy of preoperative radiotherapy combined with total mesorectal excision in the treatment of locally resectable rectal cancer: a systematic review].

OBJECTIVE: To assess the clinical efficacy of preoperative radiotherapy combined with total mesorectal excision (TME) in the treatment of locally resectable rectal cancer. METHODS: Literature search was carried out to identify prospective clinical randomized controlled trails on preoperative radiotherapy for rectal cancer published from January 1982 to April 2009. The basic characteristics and clinical efficacy of the trials meeting the screening criteria were enrolled. Date analysis was performed by RevMan 4.2. RESULTS: According to the selection criteria, 9 clinical trials were included. Compared with surgery alone, the short-term preoperative radiotherapy was associated with reduced 2-year local recurrence rate (2.4% vs 8.2%, P<0.01). There were no significant differences in 4-year overall survival (67.2% vs 66.2%), 4-year disease-free survival (58.4% vs 55.6%) and local recurrence (RR=1.16, 95% CI:0.37~3.61, P=0.80) between the preoperative radiotherapy and radiochemotherapy. High-dose preoperative radiotherapy could increase the complete response rate and sphincter sparing surgery rate than that low-dose (16.0% vs 2.0%, P<0.05). The interval between preoperative radiotherapy and operation did not affect the overall survival, disease-free survival and local recurrence. CONCLUSION: Preoperative radiotherapy combined with total mesorectal excision is associated with lower local recurrence.

[Efficacy of cetuximab in therapy of metastatic colorectal cancer: a system evaluation].

OBJECTIVE: To assess the clinical efficacy of cetuximab in the treatment of individuals with metastatic colorectal cancer. METHODS: Literature searches were performed on all clinical trails reported on target-therapy agent cetuximab in treating metastatic colorectal cancer prior to August 2008. The basic characteristics and clinical efficacy data of trials meeting the screening criteria were extracted. Date analysis was performed by RevMan 4.2 if the data came from randomized controlled trials with the same objective. RESULTS: According to the selection criteria, 22 clinical studies were included. There were 8 randomized controlled trials, 1 non-randomized controlled trial and 13 single group trials. Because of different study objectives of 8 randomized controlled trials, no data could be analyzed by the Meta-analysis method. Cetuximab plus irinotecan as second-line therapy for patients with EGFR-expressing metastatic colorectal cancer who had previously failed to respond to irinotecan-added therapy could reach a tumor response rate of 16.4% - 23.0%, and median overall survival duration of 8.6 - 10.7 months. The addition of cetuximab to irinotecan as first-line therapy to treat metastatic colorectal cancer resulted in a tumor response rate of 42.0% - 67.0%, and median overall survival duration of 33.0 months. The response rate of cetuximab combined with oxaliplatin/5-FU/LV as first-line therapy for metastatic colorectal cancer was 46.0% - 72.0% and the median duration of overall survival was 28.2 - 30.0 months. Compared with the colorectal cancer population with mutant KRAS, the patients with wild-type KRAS could obtain a higher response rate and a longer progression-free survival. CONCLUSION: Cetuximab in combination with chemotherapy has promising efficacy in the therapy of metastatic colorectal cancer, and status of gene KRAS is an independent predictive marker for response of cetuximab.