SMAD3 and colorectal carcinoma: Because the GM is known to vary from institution to institution [13], and has already been shown to affect disease phenotype of similar models such as the IL-10-/- IBD model [8] and the Pirc rat CRC model [14], we hypothesized that initial static features or subsequent dynamic shifts of the GM following Helicobacter spp.-inoculation would modulate disease incidence and severity in the Smad3-/- CRC model.