Applicability of liquid-based cytology to the assessment of DNA content in cervical lesions using static cytometry

To evaluate the nuclear DNA content of cervical lesions in liquid-based cytologic specimens prepared for static cytometry.

The DNA content of cervical lesions was evaluated in cervical samples prepared with the Autocyte PREP liquid-based cytology system (TriPath Imaging Inc., Burlington, North Carolina, U.S.A.). A series of 47 samples stained with the Papanicolaou method (chronic cervicitis, n = 15; cervical intraepithelial neoplasia [CIN] 1, n = 25; CIN 2, n = 5; CIN 3, n = 2) were collected from consecutive women enrolled in an ongoing screening study at Leonor Mendes de Barros Hospital, São Paulo, Brazil, in 2002. Each residual sample was processed according to the Feulgen-thionin method (TriPath Imaging). Ploidy evaluation was performed using the CAS 200 image analysis system and Quantitative DNA Measurement software 3.0 (version 8.1) (Becton Dickinson, San Jose, Califoria, U.S.A.). Cellular ploidy was analyzed from atypical nuclei, and the DNA index was obtained using histograms for interpretation.

All chronic cervicitis cases were diploid. Of the CIN 1 cases, 44% were diploid, 12% tetraploid, 32% aneuploid and 12% polyploid (diploid plus tetraploid). CIN 2 lesions were diploid in 60% and aneuploid in 40% of cases, whereas all CIN 3 lesions (100%) were aneuploid.

The liquid-based cytologic samples proved to be suitable and highly useful for DNA analysis by image cytometry, which was capable of discriminating CIN 3 lesions from CIN 1 and 2 but not CIN 1 from 2 lesions. Aneuploidy was closely associated with CIN 3 lesions.