High throughput single cell expression profiling: Taking a closer look on biological response

Molecular analysis of tissue and in most cases also of bodily fluids is complicated because of tissue heterogeneity and the presence of many different cell types. Even cells of apparently the same type show substantial variation in gene expression under virtually identical conditions. When analysing classical samples based on tens of thousands of cells, this natural variability among cells is lost. With the advent of real-time quantitative polymerase chain reaction (qPCR), we have a most powerful tool to study diversity on the single cell level and can detect rare cells that are critical to treatment or survival.