Most importantly, the present study highlighted for the first time the strong link existing between the transcriptome of an individual and his (her) clinical and epidemiological profile. The fact that the transcriptome tightly mirrors the variability of risk factors at a cellular level may have profound implications from a biological and clinical perspective. Until now, the traditional way of viewing the role of genes in the susceptibility to human diseases was through the effect of their variability of sequence. The present findings suggest that another important, if not greater, impact of genes on human phenotypes relates to the variability of their expression, whatever the origin of this variability. The global association observed between most cardiovascular risk factors and the transcriptome and the fact that each risk factor could be characterized by a limited and specific set of independent gene expressions further suggests that this relationship might be clinically relevant. This was particularly well illustrated by the response of the transcriptome to cigarette smoking. We showed that less than 20 genes among the 12,000 expressed in monocytes could highly discriminate smokers
