The talk will first report on a new patented method of counting CTCs based on the metabolism of tumor cells, that favors acidification of their near environment. In order to maintain the acidity produced inside the cells and communicated to the near environment (Warburg effect), we isolate each cell in a liquid pico-droplet produced in a microfluidic emulsifier. The so-produced droplets pass through a light sheet produced by a laser and the ratio of fluorescence produced at two frequencies by the SNARF dye ratiometrically measures the acidity of droplets. The first preliminary results will be shown with very limited cohort of patients, and the nature of the tumor cell found will be discussed.
As it is well known that the Veridex apparatus only counts epithelial cells, the presence in our machine of mesenchymal cells will also be discussed. In a parallel effort carried out with much more analysis precision but much less speed of execution, namely one analysis per day, we will dissect the population of cells present in patients of breast cancer carried out within a Deparray platform.
Four CD45neg cell subpopulations were identified: cells expressing only epithelial markers (E CTC), cells co-expressing epithelial and mesenchymal markers (EM CTC), cells expressing only mesenchymal markers (MES) and cells negative for every tested marker (NEG). CTC subpopulations were quantified as both absolute cell count and relative frequency. We have been able to assess the presence of cells pertaining to the above-described classes in every Metastatic Breast Cancer (MBC) patient in a cohort of 56 patients. Importantly, the fraction of CD45neg cells co-expressing epithelial and mesenchymal markers (EM CTC) was significantly associated with poorer PFS and OS, computed, this latter, both from the diagnosis of a stage IV disease and from the initial CTC assessment. Our work suggests the importance of dissecting the heterogeneity of CTC in MBC. Precise characterization of CTC could help in estimating both metastatization pattern and outcome, driving clinical decision-making and surveillance strategies.