[Chromosome effect of cyclophosphamide in various strains of mice]

The chromosomes of four different mouse strains were examined after administration of a single dose of cyclophosphamide, 100 mg/kg. Chromosomal breaks and rearrangements were produced in C3H mice three to four times as frequently and in AKR mice twice as frequently as in C57 B1 and XLII Orl mice. This indicates that cytogenetic investigations in mutation research using mice as in vivo test systems may be variable depending on the mouse strain employed. Because the effect of the alkylating agent was not pronounced in the two strains having a high incidence of cancer and leukemia (C3H and AKR), the possibility of a relationship between chromosomal instability and cancer proneness is discussed.