39 ± 1.97, 6.44 ± 1.72 mm), indicating that folic acid may prevent the growth of adenomas. Figure 2 Main results of the animal experiment after sacrificed at the 24 weeks. A. The morphology of normal colon in macroscopic observation (Upper) and microscopy (HE stained) (Lower). Neither signs of injury nor tumor were found in NS group and cFA group. B. The morphology of colon adenocacinoma in macroscopic observation (Upper) and microscopy (HE stained) (Lower). C. The incidences of DMH-induced colorectal tumor

in different groups. DMH group is 90%, which is much higher than any other groups such as FA2, FA3 which are 63%, 45% respectively. Meanwhile, there is none in NS and cFA group. D. Maximum diameter of tumor among the 5 groups (NS, cFA, DMH, FA1 and FA2). E. Tumor number in mice among the above 5 groups. Adriamycin solubility dmso (a: P < 0.05, FA3 and FA2 compared to DMH group; b: P < 0.05,

FA2 compared to FA3 group) Although the incidence in FA2 is higher than FA3, no significant difference was seen between them (63% vs 45%). However, the number and the maximum diameter learn more of the masses in FA3 group (2.11 ± 1.05, 2.11 ± 0.60 mm) showed a significant smaller than FA2 group (3.83 ± 1.11, 4.92 ± 1.24 mm), P < 0.05 (Figure 2D and Figure 2E). There is no tumor shaped and weight loss in Folic Acid control group and the mice behavior normal, so we conclude that folic acid is safe to normal colon. Meanwhile, there was no significant difference in the growth and development of mice among DMH and FA2, FA3 groups but groups between NS and DMH. Also, a macroscopic and microscopic examination of their kidneys, stomachs, lungs, liver, and spleen showed no obvious abnormalities (data not shown). FA-mediated differential gene expression profile in mouse colorectal carcinogenesis model induced by DMH With the quality control step, all twelve colonic tissues were analyzed as described in the Methods section. The microarray analysis was conducted

in the check details NS group (3 samples), DMH group (3 samples), FA2 group (3 samples) and FA3 group (3 samples). Then we compared the gene expression levels between the samples of group NS and DMH, FA3 and DMH, FA2 and FA3. A homogenous expression profile among the samples of each group was shown after the hierarchical clustering analysis. And when the Fold Change (FC) is set > 1.5 and the p value at ≤ 0.05, we found that the expression of 12395 genes was significantly altered in the DMH group compared to those in the NS group (see additional file 1). Together with the result of FA3 vs DMH (see additional file 2), we found that 642 genes down-regulated and 428 genes up-regulated in FA3 group compared to DMH, which may indicate that folic acid can reverse the gene expression that changed by DMH (see additional file 3).