Ase e = 2.7183) prior to comparison of mean levels between the three groups of patients. For the purposes of presentation, data has been reverselog transformed to allow the inclusion of units. The intra and interassay percent coefficient of variation ( CV) for NGAL and MIC1 were 4.1 , 14.3 , 5.9 and 16.1 respectively. Due to the presence of high and low standards built into the commercial kit, these coefficients were not Lixisenatide determined for CA19-9. The mean plasma concentration (after log transformation) of NGAL, MIC-1 and CA19-9 were all significantly CAL 120 chemical information higher in PC patients (111.1 ng/mL, 4.5 ng/mL, and 219.2 1531364 U/mL) than in the healthy controls (67.4 ng/mL (p = 0.01), 1.5 ng/mL (p = 0.003), and 31.5 U/mL (p = 0.001)). Additionally, serum concentration of MIC-1 and CA19-9, but not NGAL, were found to be higher in the PC patient group than in CP patients (1.6 ng/mL (p = 0.003), 31.8 U/mL (p,0.001), and 111.1 ng/mL (P.0.05) respectively) (Table 2). NGAL levels were significantly higher in patients aged 60 years or more (p = 0.045). MIC-1 levels were significantly lower in ever smokers compared to never smokers (p = 0.021). CA19-9 levels on the other hand were significantly elevated in female PC patients and in those with unresectable disease (Stage 3/4, p = 0.045 and 0.0047 respectively) (data not shown).37 U/ml 1.07 ng/ml 106 ng/ml71 94 4661 30 52Diagnostic Accuracy of NGAL, CA19-9 and MIC-We next sought to investigate the sensitivity and specificity of the three biomarkers for diagnosing PC. PC patients were divided either based on disease stage or treatment status. As post-treatment ?samples are not diagnostically relevant, only treatment naive samples were included in these analyses. In order to check diagnostic efficacy of CA19-9, MIC-1 and NGAL, these markers were evaluated at predefined cut-off of 37 U/ml, 1.07 ng/ml, 106 ng/ml as observed in earlier studies [3,6]. During this validation, NGAL was found to be 92 sensitive while MIC-1 was most specific (94 ) in distinguishing early stage 1/2 patients from healthy controls (Table 3). However, overall performance of all the markers was quite poor. Further, we evaluated their diagnostic efficacy at optimal cut-off. For CA19-9, apart from the commonly employed cut-off value of 37 U/ml, we also used optimal cut-off (55.1 U/ml) as determined by ROC curve analysis. In comparison of both PC to HC and PC to CP patients, use of an higher cut-off of CA19-9 resulted in higher specificity with similar sensitivity in 1662274 distinguishing PC from either CP or HCs (Figure 1) (Table 4). For all the further analysis, we used CA19-9 at its optimal cut-off 55.1 U/ml. Notably, CA19-9 at its optimal cut-off was 79 sensitive and 92 specific in distinguishing treatment naive PC patients from HCs. MIC-1 was the most sensitive (81 ) and CA19-9 the most specific marker (92 ) distinguishing resectable PC patients (stage 1/2) from HCs. For distinguishing resectable PC patients from CP patients, MIC-1 was the most specific (78 ) marker and NGAL was the most specific marker (100 ) in distinguishing the stage 3 and 4 PC group from CP cases.37 U/ml 1.07 ng/ml 106 ng/ml88 90 4461 30 52? ?PC patient samples were limited to treatment naive samples only for this analysis. doi:10.1371/journal.pone.0055171.tstudy. For all univariate analyses, PC was considered the disease state, with CP or healthy controls considered the control group. Multiple logistic regression was used to evaluate the performance of the bioma.Ase e = 2.7183) prior to comparison of mean levels between the three groups of patients. For the purposes of presentation, data has been reverselog transformed to allow the inclusion of units. The intra and interassay percent coefficient of variation ( CV) for NGAL and MIC1 were 4.1 , 14.3 , 5.9 and 16.1 respectively. Due to the presence of high and low standards built into the commercial kit, these coefficients were not determined for CA19-9. The mean plasma concentration (after log transformation) of NGAL, MIC-1 and CA19-9 were all significantly higher in PC patients (111.1 ng/mL, 4.5 ng/mL, and 219.2 1531364 U/mL) than in the healthy controls (67.4 ng/mL (p = 0.01), 1.5 ng/mL (p = 0.003), and 31.5 U/mL (p = 0.001)). Additionally, serum concentration of MIC-1 and CA19-9, but not NGAL, were found to be higher in the PC patient group than in CP patients (1.6 ng/mL (p = 0.003), 31.8 U/mL (p,0.001), and 111.1 ng/mL (P.0.05) respectively) (Table 2). NGAL levels were significantly higher in patients aged 60 years or more (p = 0.045). MIC-1 levels were significantly lower in ever smokers compared to never smokers (p = 0.021). CA19-9 levels on the other hand were significantly elevated in female PC patients and in those with unresectable disease (Stage 3/4, p = 0.045 and 0.0047 respectively) (data not shown).37 U/ml 1.07 ng/ml 106 ng/ml71 94 4661 30 52Diagnostic Accuracy of NGAL, CA19-9 and MIC-We next sought to investigate the sensitivity and specificity of the three biomarkers for diagnosing PC. PC patients were divided either based on disease stage or treatment status. As post-treatment ?samples are not diagnostically relevant, only treatment naive samples were included in these analyses. In order to check diagnostic efficacy of CA19-9, MIC-1 and NGAL, these markers were evaluated at predefined cut-off of 37 U/ml, 1.07 ng/ml, 106 ng/ml as observed in earlier studies [3,6]. During this validation, NGAL was found to be 92 sensitive while MIC-1 was most specific (94 ) in distinguishing early stage 1/2 patients from healthy controls (Table 3). However, overall performance of all the markers was quite poor. Further, we evaluated their diagnostic efficacy at optimal cut-off. For CA19-9, apart from the commonly employed cut-off value of 37 U/ml, we also used optimal cut-off (55.1 U/ml) as determined by ROC curve analysis. In comparison of both PC to HC and PC to CP patients, use of an higher cut-off of CA19-9 resulted in higher specificity with similar sensitivity in 1662274 distinguishing PC from either CP or HCs (Figure 1) (Table 4). For all the further analysis, we used CA19-9 at its optimal cut-off 55.1 U/ml. Notably, CA19-9 at its optimal cut-off was 79 sensitive and 92 specific in distinguishing treatment naive PC patients from HCs. MIC-1 was the most sensitive (81 ) and CA19-9 the most specific marker (92 ) distinguishing resectable PC patients (stage 1/2) from HCs. For distinguishing resectable PC patients from CP patients, MIC-1 was the most specific (78 ) marker and NGAL was the most specific marker (100 ) in distinguishing the stage 3 and 4 PC group from CP cases.37 U/ml 1.07 ng/ml 106 ng/ml88 90 4461 30 52? ?PC patient samples were limited to treatment naive samples only for this analysis. doi:10.1371/journal.pone.0055171.tstudy. For all univariate analyses, PC was considered the disease state, with CP or healthy controls considered the control group. Multiple logistic regression was used to evaluate the performance of the bioma.