Histological appearance of tissues from mice after acute exposure to MMC. Hematoxylin-eosin stained sections of mouse tissues (50%/50% C57Bl/6/129R1 genetic background) after acute exposure to 1.0 mg/kg MMC. (A and B) BM (×400); (C and D) glandular stomach (×200); (E and F) large intestine (×200). (A, C, and E) Fac+/+; (B, D, and F) Fac −/−.