PREPARATION OF FINE-NEEDLE ASPIRATION BIOPSY SAMPLES FOR FLOW CYTOMETRIC ANALYSIS

In order to improve the quality of flow cytometric (FCM) DNA histogram s, a new preparatory method was tested on samples obtained by fine nee dle aspiration biopsy (FNAB) of breast tumors. Twenty-four samples wer e obtained in vivo (group 1), and 20 were obtained from surgically res ected specimens (group 2). Tumors from both groups were aspirated twic e each. The first sample was injected directly into 70% ethanol, where as the second sample was pretreated with a mixture of Tween-20 and cit ric acid solution (Tween-20 CA) before ethanol fixation. The coefficie nt of variation (CV) of G0-G1 peaks of Tween 20 CA-pretreated samples varied from 1.85 to 5.10 (mean, 3.3) in group 1 and from 1.87 to 3.72 (mean, 2.77) in group 2. The CV of GO-G1 peaks of ethanol-preserved sa mples ranged from 2.28 to 7.22 (mean, 5.23) in group 1 and from 1.78 t o 4.04 (mean, 3.48) in group 2. The CV values of histograms obtained b y the new protocol were significantly lower (group 1, P < .05; group 2 , P < .01).