Biomarkers are products of genes that are measurable in the blood. Normally physicians rely on proteins as biomarkers (see Table), although new research is allowing detection of DNA in the bloodstream as well. Of course, you have heard of BRCA1 and BRCA2, the infamous markers of breast cancer, but some other not-so-common biomarkers include Dachshund (DACH1 and DACH2) and NEMO (no relation to ichthyosis, contrary to popular belief, but actually a regulatory subunit of the inhibitor of KB kinase complex).
Biomarkers are useful because they can indicate when a gene is being expressed and are versatile in function, from telling the sex of sturgeon at a young age in the caviar business to indicating the progression of cancerous tumors in oncology. And of course they are now available to detect the underlying genetic differences of hospitalists. After performing many ELISA assays and qPCR analyses, we found astounding differences in the gene expression of the various archetypes of physicians that you may find haunting your hospital halls. This study had IRB (irrational review of biomarker) approval.