Differential metastatic capacity of three AKR lymphoma variants.

The comprehension of tumour progression has advanced due to the use of various models, the most rewarding being probably the study of malignancy variants derived from the same tumour. In the present study the biological behaviours of three AKR lymphoma variants were compared. The three variants, TAU-33, TAU-38 and TAU-39, differed markedly in biological behaviour. The TAU-39 variant formed very large 'primary tumours', TAU-33 produced local growths of intermediate size, and TAU-38 formed small s.c. tumours. However, the metastatic potentials of the variants were inversely related to their ability to produce local tumours. According to various parameters (spread to organs, cachexia and mice mortality rate), the variant of highest metastatic potential was TAU-38, the one of intermediate ability TAU-33 and the TAU-39 had the least aggressive behaviour. A lack of difference in invasive capacity as well as a similar ranking of malignancy by both s.c. and i.v. inoculation indicate a differential behaviour in late metastasis phase. Tumour progression models may contribute to a better understanding of this threatening process and to testing of new treatment modalities suitable for cancer at different stages.