Influence of sampling practices on the appearance of DNA image histograms of prostate cells in FNAB samples

Twenty-one fine needle aspiration biopsies (FNAB) of the prostate, diagnost ically classified as definitely malignant, were studied. The Papanicolaou o r H&E stained samples were destained and then stained for DNA with the Feul gen reaction. DNA cytometry was applied after different sampling rules. The histograms varied according to the sampling rule applied. Because free cel ls between cell groups were easier to measure than cells in the cell groups , two sampling rules were tested in all samples: (i) cells in the cell grou ps were measured, and (ii) free cells between cell groups were measured. Ab normal histograms were more common after the sampling rule based on free ce lls, suggesting that abnormal patterns are best revealed through the free c ells in these samples. The conclusions were independent of the applied hist ogram interpretation method.