Casein and 3-methylcholanthrene carcinogenesis in inbred C57BL/6Os female mice

Groups of inbred C57BL/6Os female mice were subjected to one of the following -reatments: 1) subamyloidogenic administration of sodium caseinate (C group); 2) four intragastric intubations of 0.25 mg 3-methylcholanthrene (MCA) (MCA group); 3) a sodium caseinate injection followed by MCA (C-MCA group); or 4) MCA followed by a soidum caseinate injection (MCA-C group). During their life-spans, mice of the C group developed a significantly high incidence of neoplasms, especially histiocytic lymphomas, No myelogenous leukemia was observed in the C group, but it was seen in the MCA, C-MCA, and MCA-C groups. The occurrence rate of other neoplasms was significantly high in the C, MCA, and MCA-C groups, but it was not significantly high in the C-MCA group compared with the untreated group. Results suggested that sodium caseinate treatment shifts target organs in MCA carcinogenesis. In all treated groups, amyloidosis of a secondary type was observed at a significantly high rate in the following order of severity by treatment group: MCA, MCA-C, C-MCA, and C groups, MCA was obviously amyloidogenic with or without sodium caseinate adjuvant treatment; although the sodium caseinate treatment was subamyloidogenic, it elicited neoplasms, including neoplasms of lymphoreticular tissue.