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Loss of spontaneous metastasizing potential in mouse mammary tumors
1Department of Experimental Pathology, Roswell Park Memorial Institute, Buffalo, NY 14263.
Abstract:
Among 25 C3H/He and C3Hf/He spontaneous mammary tumors that all had produced pulmonary metastases in the autochthonous mice, and also produced pulmonary metastases during subsequent sequential syngeneic intramammary passages, three were observed to stop producing metastases. The specific investigation of the observed changes in behavior is described. When the tumors were re-started in serial intramammary passage from early, cryopreserved transplant generations, the loss of metastasizing potential reoccurred in the same, or in nearly the same, transplant generations. In one tumor from which three transplant lines had been established, the metastasizing potential was lost in all transplant lines during closely related transplant generations. It seems that a spontaneous reduction of malignant behavior in mouse mammary tumors may be an occasional neoplastic characteristic, and that the observed losses of metastasizing potential may have been determined by a programmed genetic change.
Insights
Three mouse mammary tumors spontaneously lost their ability to metastasize during serial passages. This loss of malignant behavior appears to be a programmed genetic change in these neoplasms.
Area of Science:
- Oncology
- Cancer Metastasis Research
- Mouse Models in Cancer
Background:
- Spontaneous mammary tumors in C3H/He and C3Hf/He mice are known to metastasize.
- Sequential syngeneic intramammary passages are used to study tumor behavior.
Purpose of the Study:
- To investigate the phenomenon of spontaneous loss of metastatic potential in mouse mammary tumors.
- To determine if this loss is a reproducible characteristic and potentially genetically determined.
Main Methods:
- Studied 25 spontaneous mammary tumors from C3H/He and C3Hf/He mice.
- Utilized sequential syngeneic intramammary passages.
- Re-initiated tumor lines from cryopreserved early transplant generations.
Main Results:
- Three out of 25 tumors ceased producing pulmonary metastases during serial passages.
- The loss of metastasizing potential reoccurred in similar transplant generations when lines were re-started.
- In one tumor with three lines, all lines lost metastatic potential concurrently.
Conclusions:
- Spontaneous reduction in malignant behavior, specifically loss of metastasizing potential, can occur in mouse mammary tumors.
- This loss may represent an occasional neoplastic characteristic driven by a programmed genetic change.