MSH2 and intestinal neoplasm: In order to gain insights in potential mechanisms that govern the reduction in intestinal tumorigenesis in SPF Msh2-Lynch mice, we performed whole exome sequencing on the single intestinal tumor that we obtained in the SPF facility and on tumors that arose spontaneously or in response to TMZ in conventional Msh2-Lynch mice as described in Wojciechowicz et al. (2014).9 Mutational analysis of the tumors that developed in TMZ-treated, conventionally housed Msh2-Lynch mice revealed a high total mutational burden, as would be expected (Figure 1(h)).