In the August 15, 2004, issue of Clinical Cancer Research, Nielsen and colleagues demonstrated how a cancer subtype identified by gene expression profiling could be validated using a widely accessible technology (immunohistochemistry). This opened the door to large-scale studies of archival cohorts and clinical trials, which allowed detailed clinical understanding of a new genomic discovery.
Nielsen, T. O., & Perou, C. M. (2015, April 15). CCR 20th anniversary commentary: The development of breast cancer molecular subtyping. Clinical Cancer Research. American Association for Cancer Research Inc. https://doi.org/10.1158/1078-0432.CCR-14-2552