N. P. Omesiete1, J. Jandova1, K. Memeh1, V. Nfonsam1 1University of Arizona,Surgery,Tucson, AZ, USA 2University of Arizona,Surgery,Tucson, AZ, USA
Introduction:
There has been a steady rise in the incidence of early onset colon cancer (EOCC); age <50. Recent studies suggest that EOCC may be a biologically distinct disease from late onset CC (LOCC). Our previous study showed COMP is upregulated in EOCC compared to LOCC patients and its elevation is associated with tumor aggressiveness and poor survival. The aim of this study was to evaluate COMP as a potential plasma biomarker and to assess its correlation with carcinoembryonic antigen (CEA) level in patients with EOCC.
Methods:
Fresh frozen plasma samples were obtained from our Colorectal biorepository belonging to 16 patients with early and late onset CC (8 patients in each cohort). The samples were matched for stage of disease. An ELISA assay using Human COMP Quantikine ELISA Kit purchased from R&D Systems was performed using 50 ul of 100X diluted plasma sample according to the manufacturer’s protocol. COMP was detected in all the samples of patients with colon cancer. A quantitative analysis was performed to determine the levels of COMP in each sample by normalizing the COMP protein to total protein. This was accomplished using A Pierce BCA protein assay kit from Thermo scientific. Analysis was performed to compare the levels of COMP between both groups and their CEA levels pre-treatment.
Results:
There were a total of 16 patients (8 males and 8 females). Mean age was 42 years for EOCC and 70 years for LOCC. The patients were propensity matched for stages. There was 1 stage I; 2 stage II; 3 stage III and 2 stage IV in each cohort. COMP was detected in all 16 serum samples. Mean COMP levels was 140 pg of COMP/ug of total protein in EOCC and 20 pg of COMP/ug of total protein in LOCC, indicating a seven fold difference between the cohorts, p <0.005. There was also a positive correlation between COMP and the pre-treatment CEA levels for each stage of disease in each cohort. This was however not statistically significant.
Conclusion:
Our findings suggest that COMP is differentially and significantly elevated in EOCC with good correlation with an established biomarker CEA. COMP may be useful as a biomarker in EOCC.