Molecular profiling of individual tumor cells by hyperspectral microscopic imaging.

We developed a hyperspectral microscopic imaging (HMI) platform that can precisely identify and quantify 10 molecular markers in individual cancer cells in a single pass. The exploitation of an improved separation of circulating tumor cells and the application of HMI provided an opportunity (1) to identify molecular changes in these cells, (2) to recognize the coexpression of these markers, (3) to pose an important opportunity for noninvasive diagnosis, and (4) to use targeted therapy. We balanced the intensity of 10 fluorochromes bound to 10 different antibodies, each specific to a particular tumor marker, so that the intensity of each fluorochrome can be discerned from overlapping emissions. Using 2 touch preps from each primary breast cancer, the average molecular marker intensities of 25 tumor cells gave a representative molecular signature for the tumor despite some cellular heterogeneity. The intensities determined by the HMI correlate well with the conventional 0-3+ analysis by experts in cellular pathology. Because additional multiplexes can be developed using the same fluorochromes but different antibodies, this analysis allows quantification of many molecular markers on a population of tumor cells. HMI can be automated completely, and eventually, it could allow the standardization of protein biomarkers and improve reproducibility among clinical pathology laboratories.