Correlation Between The Expression Of Fatty Acid Binding Protein 4 And Fatty Acid Binding Protein 6 And The Incidence Of Colorectal Cancer

Objective To investigate the relationship between the expression of fatty acid binding protein 4and fatty acid binding protein 6 and the incidence of colorectal cancer and its value as a biomarker for diagnosis of colorectal cancer(CRC).Methods From September 2017 to December 2018,a total of 100 patients who were hospitalized at the First Affiliated Hospital of Anhui Medical University and diagnosed with CRC for the first time after postoperative histopathology were recruited and was set as the case group,and 100 patients who underwent total colonoscopy were recruited and was set as the control group,respectively.The serum levels of FABP4 and FABP6 in CRC patients in the control group and the case group were detected by enzyme linked immunosorbent assay(ELISA)before and 2 weeks after radical mastectomy.The expressions of FABP4 and FABP6 proteins in CRC tissues and adjacent tissues were observed by immunohistochemistry and western blotting.Multivariate Logistic regression analysis was used to explore the risk factors affecting the occurrence and development of CRC.The receiver operating characteristic curve analysis was used to evaluate the diagnostic efficacy of FABP4 and FABP6 levels on CRC.Results1.The serum levels of FABP4 and FABP6 in patients with CRC before surgery were higher than the levels in the controls(P<0.001),and significantly decreased at 2 weeks after surgery,but still higher than those in the control group(P<0.001).2.Immunohistochemistry showed that FABP4 and FABP6 were mainly distributed in the cytoplasm of human colorectal tumor tissues,and only a small amount distributed in adjacent tissues.3.Western blot revealed that the proteins expression of FABP4 and FABP6 were significantly higher in tumor tissues than in adjacent tissues(P<0.001,P=0.002,respectively).4.Chi-square test results suggest that tumors with high-and low FABP4 and FABP6 expression has no significant correlation in tumor size,tumor site,distant organ and lymph node metastasis,histologic grade,lymphatic permeation,neurological invasion,vascular invasion,Dukes and TNM classification(P>0.05).5.Spearman correlation analysis showed that in the CRC group,the level of FABP4 was positively correlated with body mass index(BMI),waist-to-hip ratio(WHR)and triacylglycerol(TG)(BMI: r = 0.277,P = 0.005;WHR: r = 0.182,P = 0.040;TG: r =0.215,P = 0.013),the level of FABP6 was positively correlated with systolic blood pressure(SBP)and diastolic blood pressure(DBP)(SBP: r = 0.248,P = 0.013;DBP: r =0.291,P = 0.003);in the normal control group,the level of FABP4 was positively correlated with BMI and WHR(BMI : r = 0.227,P = 0.024;WHR: r = 0.179,P = 0.048).Furthermore,no significant correlation was found between FABP4 and FABP6 and age,gender,fasting plasma glucose(FPG),total cholesterol(TCH),high density lipoprotein(HDL-C),low density lipoprotein(LDL-C),carcinoembryonic(CEA)and carbohydrate antigen 19-9(CA19-9)in both groups.6.Multivariate logistic regression analysis showed that FABP4,FABP6,WHR,LDL-C,CEA,CRC family history,and high-fat diet were independent risk factors for CRC(adjusted OR = 1.916,95% CI 1.340-2.492,P <0.001;OR = 2.162,95% CI1.046-1.078,P <0.001;OR = 2.084,95% CI 0.949-4.578,P = 0.047;OR = 4.197,95%CI 3.144-5.393,P <0.001;OR = 1.713,95% CI 1.036-3.236,P = 0.040;OR = 1.632,95% CI 1.014-2.118,P = 0.042),and HDL-C is a protective factor for the incidence of CRC(corrected OR = 0.124,95% CI 0.057-0.274,P <0.001).7.ROC curve analysis show that the areas under the curve(AUC)for FABP4 and FABP6 diagnosis of CRC are 0.658(95%CI 0.598-0.714),0.683(95%CI 0.624-0.738),respectively.The optimal sensitivity of FABP4 and FABP6 were 93.20%(95%CI87.8-96.7)and 83.70%(95%CI 76.7-89.3),respectively,while the optimal specificity of FABP4 and FABP6 were 48.8%(95%CI 39.8-57.9)and 58.4%(95%CI 49.2-67.1),respectively.When combined detection of serum carcinoembryonic(CEA)and FABP4 and FABP6,the optimal sensitivity and specificity were 61.33%(95%CI 53.0-69.2)and79.82%(95%CI 71.3-86.8),respectively.Conclusion Increased expression of FABP4 and FABP6 is not only a risk factor for the onset of CRC,but also may have potential value as a diagnostic biomarker for CRC.Combined detection of CEA with FABP4 and FABP6 could improve the diagnostic efficacy of CRC.