GSTM1 and colorectal neoplasm: In contrast, iron-supplemented mice treated with F. rodentium or H. biformis presented with reduced colorectal tumor burden as evidenced by tumor count (Fig. 4C; P < 0.001), size (Fig. 4D; Fr: P < 0.05, Hb: P < 0.001), grade (Fig. 4E; Fr: P < 0.05, Hb: P < 0.001), and Ki- 67 (Fig. 4F; P < 0.001).