DNA analysis of breast cancer by flow cytometry & correlation with other prognostic parameters.

Flow cytometric estimation of DNA content (ploidy and S-phase fraction--SpF) was done on breast cancer tissues from 171 patients. Twenty eight per cent of the tumours were diploid and 72 per cent were aneuploid. SpF was measurable in 82 DNA histograms; of these 22.4 per cent had SpF less than 10 per cent, 34.1 per cent had SpF between 10-20 and 43.5 per cent had SpF greater than 20 per cent. The mean SpF of the measurable histograms was 19.01 per cent with a range 1.78 to 45.19 per cent. A significant correlation between DNA ploidy and SpF was observed (P less than 0.01). Eighty nine per cent of diploid tumours had SpF less than 10 per cent and 73 per cent of aneuploid tumours had SpF greater than 20 per cent. A significant correlation was also found between ploidy and SpF and oestrogen receptor (ER) status of the tumours (P less than 0.05) and between SpF and progesterone receptor (PgR) status of the tumours (P less than 0.05), but not between ploidy and PgR status of the tumours. A significant direct correlation was observed between SpF and tumour grade (P less than 0.05), but not between ploidy and tumour grade. No correlation was observed between DNA ploidy and SpF and tumour type, tumour size, axillary lymph node involvement, age and menopausal status of the patients. Although the incidence of breast cancer is one-third of that reported in the Western countries, there is apparently no biological difference between the various parameters studied.