High content screening: seeing is believing

High content screening (HCS) combines the efficiency of high-throughput techniques with the ability of cellular imaging to collect quantitative data from complex biological systems. HCS technology is integrated into all aspects of contemporary drug discovery, including primary compound screening, post-primary screening capable of supporting structure-activity relationships, and early evaluation of ADME (absorption, distribution, metabolism and excretion)/toxicity properties and complex multivariate drug profiling. Recently, high content approaches have been used extensively to interrogate stem cell biology. Despite these dramatic advances, a number of significant challenges remain related to the use of more biology- and disease-relevant cell systems, the development of informative reagents to measure and manipulate cellular events, and the integration of data management and informatics.