PURPOSE: Inflammatory genes and microRNAs have roles in colon carcinogenesis; 
therefore, they may provide useful biomarkers for colon cancer. This study 
examines the potential clinical utility of an inflammatory gene expression 
signature as a prognostic biomarker for colon cancer in addition to previously 
examined miR-21 expression.
EXPERIMENTAL DESIGN: Quantitative reverse transcriptase-PCR. was used to measure 
the expression of 23 inflammatory genes in colon adenocarcinomas and adjacent 
noncancerous tissues from 196 patients. These data were used to develop models 
for cancer-specific mortality on a training cohort (n = 57), and this model was 
tested in both a test (n = 56) and a validation (n = 83) cohort. Expression data 
for miR-21 were available for these patients and were compared and combined with 
inflammatory gene expression.
RESULTS: PRG1, IL-10, CD68, IL-23a, and IL-12a expression in noncancerous 
tissue, and PRG1, ANXA1, IL-23a, IL-17a, FOXP3, and HLA-DRA expression in tumor 
tissues were associated with poor prognosis based on Cox regression (/Z-score/ 
>1.5) and were used to generate the inflammatory risk score (IRS). IRS was 
associated with cancer-specific mortality in the training, test (P = 0.01), and 
validation (P = 0.02) cohorts. This association was strong for stage II cases (P 
= 0.002). Expression of miR-21 was associated with IL-6, IL-8, IL-10, IL-12a, 
and NOS2a, providing evidence that the function of this microRNA and these 
inflammatory genes are linked. Both IRS and miR-21 expression were independently 
associated with cancer-specific mortality, including stage II patients alone.
CONCLUSION: IRS and miR-21 expression are independent predictors of colon cancer 
prognosis and may provide a clinically useful tool to identify high-risk 
patients.