Fine needle biopsy as a method for following ploidy changes in the Dunning R-3327 rat prostate tumour

The use of fine needle biopsies for the collection of cells for flow cytometry was investigated using the Altman Dunning R-3327 rat prostate tumour. Five rats were castrated 150 days after tumour implantation. Multiple fine needle biopsies were performed 138, 194 and 220 days post implantation and the results compared to those from intact animals. A small aneuploid peak was found at the 2.8c position in intact animals. Although tumour growth was slowing down in castrates, indicating hormone independency but sensitivity, no change in flow cytometric profile could be demonstrated. This indicates that, in this model, no correlation between aneuploidy and hormone independence exists. The fine needle biopsy method proved to be easy and reliable for tumours of above 1 cm3 in volume.