DNA flow cytometry on breast carcinomas: comparison of a detergent and an enzyme-detergent preparation method

In this study we have compared two different preparation methods for DNA flow cytometry on breast cancer. Tumour cell suspensions from 49 breast cancers were analysed on a Facscan flow cytometer. In seven of 49 cases, additional aneuploid peaks were found after enzyme/detergent treatment (E/D), not seen after the detergent (D) preparation. S-Phase fractions were significantly higher after D than after E/D preparation (mean values, 15 and 8%, respectively), although the correlation was high between the two methods. S-Phase fraction estimated after background correction diminished the differences between the two methods (mean values, 8 and 6%). Furthermore, the fraction of G2/M cells were generally greater with the D method. These differences can be explained by increased number of cell doublets and nuclear fragments after D compared to E/D preparation. This clearly shows that the preparation method influences the result of DNA flow cytometry on human breast cancers.