B58
High DNA content is associated with poor prognostic features in primary breast cancer
Jasbani Dayal1, Norman Pratt1, David Kellock1, Colin Purdie1, Mark Sales1, Philip Quinlan1, Willem Corver2, Natalja Terhaar2, Alastair Thompson1
1University of Dundee, UK, 2Leiden University Medical Center, Leiden, Netherlands
Background
DNA content analysis using flow cytometry (FCM) is a robust and reliable method to determine ploidy level in clinical cancers. Previous work has provided data correlating ploidy status with tumour grade, p53 mutation status, disease recurrence and survival, suggesting a prognostic significance of DNA content analysis in breast cancer. The purpose of this study was to analyse and categorise formalin fixed paraffin embedded (FFPE) breast cancers using the triple staining FCM technique to enable an accurate assessment of tumour ploidy by differential staining of epithelial and stromal cell populations. Data generated was compared with p53 mutation status, morphological and histopathological parameters for the same breast tumours.
Method
FFPE tissue sections from 200 breast carcinomas were processed as described by Corver, W.E., et al (2005). DNA content was analysed using a Becton Dickenson FACScan and the CellQuest (3.1) software. Ploidy data was compared with other clinical parameters including p53 mutation status using an in house data analysis tool (INSPIRE) that includes the two tail Fishers exact test for statistical analysis.
Results
Breast carcinomas were categorised into near diploid, high DNA content (HDC), near tetraploid and mixed tumours. Near diploid tumours showed a strong association with tumour grade 1 and 2 (P = 0.0001) and ER positive status (P = 0.0023). HDC tumours significantly associated with features of poor prognosis such as tumour grade 3 (P = .0018), p53 mutant (P = 0.0023) and ER negative status (P = 0.0098). Near tetraploid and mixed tumours did not show any significant correlations.
Conclusion
The triple staining technique allowed an accurate evaluation of ploidy status in breast carcinoma and differentiated near diploid from HDC cancers. This further enabled an association of HDC tumours with poor prognostic features in breast cancer.
References
[1] Corver, W. E.,et al (2005). Journal of Pathology 206, 233-241
