Search

Aims: Aneuploidy is a potential biomarker for predicting progression of premalignancies. Ploidy assessment is mostly performed on nuclei isolated from tissue sections. Ploidy assessment in situ in tissue sections may be a large improvement, enabling selective sampling of nuclei, thus allowing the correlation between ploidy and histology. Existing ploidy analysis methods in sections suffer from limited sensitivity. The aim was to reliably assess ploidy in sections, combined with simultaneous assessment of other markers at the individual cell level. Methods and results: Ploidy was measured in 22 paraffin-embedded oral premalignancies. The DNA stoichiometric Feulgen procedure was used on isolated nuclei, as well as fluoresence in situ hybridization analysis. In tissue sections, Feulgen was combined with immunohistochemistry for Ki67 proliferation marker, enabling distinction between cycling euploid and aneuploid cells. Aneuploidy was reliably detected in tissue sections (sensitivity 100%, specificity 92%). One section in which aneuploidy was detected was misclassified in isolated nuclei analysis. Sections were also successfully analysed using our model combined with DNA double strand break marker gamma-H2AX in fluorescence microscopy, underlining the power of biomarker evaluation on single cells in tissue sections. Conclusions: The analysis model proposed in this study enables the combined analysis of histology, genotypic and phenotypic information.

The introduction of new technologies, designed to assess biologically relevant alterations in tumour cells, has the potential to provide additional prognostic and predictive information from biopsies, as well as providing a more objective assessment than conventional histopathology alone. One such technique is the assessment of the ploidy status of tumours. DNA ploidy studies, using various technologies, are abundant in the literature, but questions remain as to how such studies should be translated into evidence-based practice. In this Expert Opinion, we provide two perspectives on this field. Baak and Janssen discuss the technology and set the assessment of ploidy in the context of other quantitative techniques. Clinical applications are then illustrated. In the paper by Peter Hall, aspects of the biology of ploidy are discussed, and the potential relevance of a more detailed understanding of the biology of ploidy to clinical application. Some of the general short-comings of the applied literature are discussed and some approaches suggested for the improvement of the evidence base on which healthcare decisions relating to the application of new technologies are made.