Cell transformation assay using Balb/c 3T3 cells or Bhas 42 cells for the efficient detection of tumour promoters.

In this paper, we report three interlaboratory validation studies with special interest in detecting tumour promoters. The former two validation studies were on the improved two-stage in vitro transformation assay using Balb/c 3T3 cells. The third one was on the Bhas 42 cell assay. From the results, we could confirm that, on the whole, the improved two-stage transformation assay was sensitive, reproducible and reliable, while the Bhas 42 cell assay was a very sensitive and reproducible method for detecting tumour-promoting potential. However, there was some variation in the sensitivity among the laboratories. In order to cope with this sensitivity variation, further refinement is necessary, which will increase the applicability of the methods.