Abstract
Increased total serum concentrations of human neutrophil peptide-1, -2 and -3 (HNP-1, -2 and -3) have been associated with colorectal cancer (CRC). Owing to a recently developed and fully validated liquid-chromatography coupled to tandem-mass spectrometry (LC-MS/MS) assay, individual serum concentrations of these antimicrobial peptides were quantified to evaluate their role as serum markers in CRC. Serum was obtained from patients with indications for colonoscopy, subsequently diagnosed as normal colon or hyperplastic polyp (CON; n= 368), adenomatous polyp (AP; n = 179) or colorectal cancer (CRC; n = 69). Comparison of HNP-1, -2 and -3 concentrations between CRC and CON (130 ± 90 vs. 105 ± 80; 264 ± 140 vs. 206 ± 99 and 62 ± 56 vs. 54 ± 59 for HNP-1, -2 and -3, respectively) revealed that reported up-regulated total HNP-concentrations can be largely attributed to increased HNP-2 (P=0.0006) and HNP-1 (P=0.024) levels. Although receiver operating characteristics (ROC) analyses showed low specificity of the peptides for CRC and no significant changes in serum levels were observed after surgical removal of the tumor (n=23), the established differentiation between the HNP-subtypes may be particularly useful to completely elucidate the role of these antimicrobial peptides in CRC.