Comparison of the relative GLUT1 mRNA expression levels of SW480 and SW620 cell lines between normoxia and hypoxia conditions. The results showed that the relative GLUT1 mRNA expression level was elevated in cells exposed to hypoxia. The relative GLUT1 mRNA expression ratio of SW480 cell lines were 1.24-fold (hypoxia/normoxia: 2.37/1.91; after 24 h incubation) and 1.66-fold (hypoxia/normoxia: 3.89/2.34; after 48 h incubation); however, there was a 1.39-fold (hypoxia/normoxia: 2.48/1.79; after 24 h incubation) and a 1.72-fold elevated GLUT1 mRNA expression (hypoxia/normoxia: 4.43/2.58; after 48 h incubation) in SW620 cell lines. The control groups were incubated in humidified atmospheric air without the addition of CO2. Values shown are means ± SD of 3 independent experiments with triplicate specimens.