Comparative Serum Proteomic Analysis of Serum Diagnosis Proteins of Colorectal Cancer Based on Magnetic Bead Separation and MALDI-TOF Mass Spectrometry

Background: At present, the diagnosis of colorectal cancer (CRC) requires a colorectal biopsy which is aninvasive procedure. We undertook this pilot study to develop an alternative method and potential new biomarkersfor diagnosis, and validated a set of well-integrated tools called ClinProt to investigate the serum peptidome inCRC patients.
Methods: Fasting blood samples from 67 patients diagnosed with CRC by histological diagnosis,55 patients diagnosed with colorectal adenoma by biopsy, and 65 healthy volunteers were collected. Division wasinto a model construction group and an external validation group randomly. The present work focused on serumproteomic analysis of model construction group by ClinProt Kit combined with mass spectrometry. This approachallowed construction of a peptide pattern able to differentiate the studied populations. An external validationgroup was used to verify the diagnostic capability of the peptidome pattern blindly. An immunoassay methodwas used to determine serum CEA of CRC and controls.
Results: The results showed 59 differential peptidepeaks in CRC, colorectal adenoma and health volunteers. A genetic algorithm was used to set up the classificationmodels. Four of the identified peaks at m/z 797, 810, 4078 and 5343 were used to construct peptidome patterns,achieving an accuracy of 100% (> CEA, P < 0. 05). Furthermore, the peptidome patterns could differentiate thevalidation group with high accuracy close to 100%.
Conclusions: Our results showed that proteomic analysisof serum with MALDI-TOF MS is a fast and reproducible approach, which may provide a novel approach toscreening for CRC.