Neoplastic behavior of chromosomally abnormal clones in New Zealand Black mice.

Old New Zealand Black (NZB) mice frequently develop reticulum-cell sarcoma and clones of aneuploid cells in their spleens. In order to define the relationship between neoplasms and chromosomal abnormalities, the pattern of distribution of aneuploid cells was studied to see if it corresponds to that expected of the malignancy, and chromosomally aberrant or normal spleen cells were transplanted into syngeneic newborn recipients. The results indicate that aneuploid cells arise focally but may disseminate widely in an affected mouse. A strong association was found between spleen-cell aneuploidy in a transplantation donor and both aneuploidy and histological evidence of reticulum-cell sarcoma in young recipients. Chromosomal aberrations in young recipients were always of donor origin. On the basis of these data, it seems likely that aneuploid clones which arise in the spleens of old NZB mice usually are at least potentially neoplastic.