COMPARISON OF GROWTH-RATE OF 2 B16 MELANOMAS DIFFERING IN METASTATIC POTENTIAL IN YOUNG VERSUS MIDDLE-AGED MICE

The rise of cancer frequency as a function of age is a well-establishe d fact. The aspect of the host age-tumor progression relationship, nam ely the slower metastatic spread in aged patients, has been investigat ed to a lesser extent. In the present study, we examined whether host- age-dependent growth rate varies with metastatic capacity of the tumor . The parental B16 and the B16/Col/R, a highly metastatic variant, wer e employed. A more pronounced growth of both tumors in young as compar ed to middle-aged mice was found. However, the differential growth in middle-aged versus young mice was more evident in the highly metastati c variant. According to the tumor size data, a sixfold growth reductio n in middle-aged mice was observed with B16/Col/R and an only twofold growth reduction was seen with the B16 melanoma. The data might eventu ally contribute to the finding of more appropriate treatment modalitie s for the middle-aged cancer patient.