Breast cancer heterogeneity assessed by flow cytometry

The natural history of breast cancer is characterized by a marked heterogeneity within and between patients. During the clinical phase, there is ample opportunity for clonal mutation and evolution, and it seems probable that almost all breast cancer patients have multiple tumor clones, each with its own growth requirements, growth rate, ability to metastasize and sensitivity to drugs. Flow cytometry (FCM) is a technique which can rapidly and quantitatively measure a wide variety of cellular features. This can explain its large employment in the development and validation of tumor markers for prognostic and therapeutic purposes. The study of DNA content and cell cycle represents the most common application of FCM on solid tumor analysis. The use of monoclonal antibodies raised against functional and phenotypic cell markers can improve the suitability of FCM to assess the prognostic significance of these parameters; at the same time it could provide a helpful tool for a combined investigation of differentiation, proliferation and aggressiveness tumor markers, and their clinical relevance.