Emerging applications of single-cell diagnostics.

The performance of DNA sequencers (next generation sequencing) is rapidly enhanced these days, being used for genetic diagnostics. Although many phenomena could be elucidated with such massive genome data, it is still a big challenge to obtain comprehensive understanding of diseases and the relevant biology at the cellular level. In general terms, the data obtained to date are averages of ensembles of cells, but it is not certain whether the same features are the same inside an individual cell. Accordingly, important information may be masked by the averaging process. As the technologies for analyzing bio-molecular components in single cells are being developed, single cell analysis seems promising to address the current limitations due to averaging problems. Although the technologies for single cell analysis are still at the infant stage, the single cell approach has the potential to improve the accuracy of diagnosis based on knowledge of intra- and inter-cellular networks. In this review several technologies and applications (especially medical applications) of genome and transcriptome analysis or single cells are described.