Amplification of Oncogenes in Early-Stage, Radiation-Induced Rat Skin Tumours.

摘要

The effect of gene amplification on tumour size and growth was investigated in 39 samples collected from 23 radiation-induced rat skin tumours. The relationships of both the time from irradiation and the time from first appearance of the tumour to gene amplification were also examined. DNA from each tumour sample was extracted and probed for abl, fos, c-myc, N-myc, H-ras, and K-ras, and amplification of all but N-myc was detected. A single amplified gene was observed in 8 of 39 samples; multiple amplified genes were found in an additional 7. The amplification of c-myc, H-ras, or K-ras was found to be associated with increase in tumour size. c-myc amplification was also associated with an increase in growth rate. Amplification of c-myc was found to occur as a late-stage event in these tumours. The results suggest that both myc and ras genes play unique roles in the growth and development of radiation tumours, and they provide new information on the temporal aspects of c-myc activation. 77 refs., 26 figs., 11 tabs.