A. Dragon mRNA expression in different organs of normal mice. Total RNA was extracted from the colon, intestine, stomach, liver, spleen and kidney for RT-PCR to determine Dragon mRNA expression. GAPDH was used as a control. B. Experimental protocol for CAC induction. Mice were injected intraperitoneally with AOM at a dose of 12.5 mg/kg body weight. One week after the injection, 3% DSS was administered to mice via their drinking water for 5 days, and they were then switched to normal drinking water for 16 days. The treatments were repeated for three cycles. C. Hematoxylin-Eosin staining of the normal colon a. and CAC lesion b. D. Expression of Dragon mRNA in colon cancer tissues. Real-time PCR analysis was performed to determine Dragon expression in normal colons and colon cancer tissues. Tissues from 3 different sites of the normal colon or colon cancer were used for each mouse (n = 6, *P < 0.05). E. and F. Dragon mRNA and protein expression in tumor lesions collected from human CRC patients were analyzed. Normal tissues at the distance of 5 cm from the surgical margins were used as controls. (E., left panel 1) Dragon mRNA expression in human colorectal cancer lesions and normal tissues. 68 patients were used. (E., right panels) Dragon mRNA expression in human colorectal cancer lesions at different stages. Colorectal tumor tissues and normal tissues collected at stage I (n = 9), II (n = 19), III (n = 24) and IV (n = 16) were used to measure Dragon mRNA levels. F. Dragon protein expression in human colorectal cancer lesions at different stages. Colorectal tumor tissues and normal tissues collected at stage I (n = 7), II (n = 14), III (n = 19) and IV (n = 14) were used to measure Dragon protein by Western blotting. The upper panels are representatives of the Western blots at different stages, and the lower panels are densitometric analyses of the Western blots at corresponding stages. N.S., not significantly different; *P < 0.05; **P < 0.01.