AUTOMATED ASSESSMENT OF NUMERICAL CHROMOSOMAL-ABERRATIONS IN PARAFFIN-EMBEDDED PROSTATE TUMOR-CELLS STAINED BY IN-SITU HYBRIDIZATION

We investigated the feasibility of automated counting of in situ hybri dization signals (ISH) in interphase cells isolated from paraffin embe dded prostate tissue. In total, 34 specimens from 7 patients with pros tate cancer were stained with probes specific for the centromeric regi ons of chromosomes Y, 1, 7, 8, 10, and 15, using an immunoperoxidase b ased technique suitable for bright-field microscopy. Enumeration of th e number of ISH spots of 500 nuclei per specimen was performed (1) usi ng an automatic system developed without any human intervention and (2 ) using the same system, but including verification of the counts base d on visual inspection of the stored images. As reference from each sp ecimen, 200 cell nuclei were evaluated manually, using conventional mi croscopy. A typical analysis procedure (including user verification) t ook 35 min. The difference (root mean error) between the automated cou nting and the counting after visual interaction was relatively small ( 15%). The percentage of cells with incorrect counts by automated analy sis was 20.2%, a number that could easily be improved by user interact ion. Detection of cells with aneusomy proved to be more sensitive comp ared to the routine manual counting, in cases where aberrant frequenci es were low. Automated counting of samples with law frequencies (<10%) resulted in a higher frequency of aberrant cells in 9 of 11 cases, pr obably due to the fact that an unbiased cell selection is guaranteed. Automated assessment of ISH signals is considered useful for the evalu ation of chromosomal aberrations in prostate tumor cells, provided tha t the counts are visually confirmed. (C) 1996 Wiley-Liss, Inc.