Comparative flow DNA analysis of different cell suspensions in breast carcinoma

This study compared three methods of dissociation of breast lesions for DNA flow cytometry. Eleven benign lesions and 66 cancers were dissociated using mechanical, Ficoll, or enzymatic methods. DNA flow analysis showed that the DNA index did not vary from one method of dissociation to another. All benign lesions were diploid and 67% of all cancers were aneuploid. Enzymatic dissociation gave a lower percentage of aneuploid cells with a diminution of the proportion of cells in the G2 + M phase (13.2% enzymatic against 17.6% Fi-coll); on the other hand, it provided cell populations of greater viability than the other methods (32.6% enzymatic, 17.2% Fi-coll; P less than 0.01). The mechanical and Ficoll suspensions did not differ significantly when they were analyzed on the basis of their DNA content and their cellular viability. When compared with mechanical preparation, Ficoll suspension showed a lower recovery of tumor cells, but this inconvenience was compensated for by a more homogeneous aspect where the contribution of aggregates and debris was clearly lessened. Therefore, this study led us to choose Ficoll suspension for subsequent flow analysis of breast tumors.