FLOW-CYTOMETRY ANALYSIS OF MALIGNANT-TUMORS OF THE HEAD AND NECK - DIFFERENCES BETWEEN 2 METHODS IN THE RECOGNITION OF ANEUPLOIDY

DNA aneuploidy, which reflects changes in nuclear DNA-content, as dete rmined cytometrically is a candidate prognostic factor in squamous cel l carcinoma of the head and neck. The aim of this study was to compare two different preparation methods with respect to their use in detect ing aneuploid tumor cell populations in malignant tumors of the head a nd neck. Fresh frozen tumor material was used. The methods compared we re a multistep procedure (A) including fixation of cells and enzymatic treatment, and a one step procedure (B). Both include RNAse and the u se of propidium iodide for DNA staining. Forty-seven percent of the tu mors were non-diploid according to method A, and 29% according to meth od B, discordant findings being made in 15 tumors, only two of which w ere non-SCC. Defining a 'true non-diploid tumor' in this series as a t umor with a DNA index outside the range of diploidy detected either by method A or B, 59% (29/49) of the tumors were non-diploid. The sensit ivity was 0.48 (14/29) for method B and 0.79 (23/29) for method A. The striking differences in accuracy between methods A and B emphasize th e need of caution when new methods are introduced, and when results ob tained with different methods are compared. Copyright (C) 1996 Elsevie r Science Ireland Ltd.