Real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to evaluate gene expression of adenosine kinase, a key enzyme in adenosine metabolism, in human intestinal biopsy specimens of 10 colorectal cancer patients. Quantitative mRNA expression levels were normalized against the reference gene beta-actin. The results showed that adenosine kinase gene expression was significantly higher in cancer than in normal-appearing tissue, in line with our previous measurements of adenosine kinase enzyme activities in colorectal tumor samples.