Quality assurance in clinical trials--the role of pathology.

In the last two decades, our knowledge about cancer genetics and cancer biology increased exponentially. Deep sequencing now allows rapid and cost-effective analysis of entire cancer genomes. Dysregulation of cell growth, cell survival, tissue homeostasis, and immune surveillance have been recognized as hallmarks of cancer. In parallel, diagnostic surgical pathology has been harmonized and consensus diagnostic criteria for cancer classification have been developed by initiatives of the World Health Organization, the International Agency for Research on Cancer, and the Union for International Cancer Control. Pharmaceutical companies developed novel drugs targeting specific molecules in signaling pathways, which has allowed the development of the concept of precision medicine. Now, we are facing a large number of clinical trials which bring together these advances and will explore efficacy of novel treatment regimens. Assessment of the efficacy of a new drug is often coupled with the simultaneous assessment of the capacity of tissue-based biomarkers to predict response of individual patients (companion diagnostics/precision medicine). Patients with histologically similar tumors might respond differently to the same drug. This review summarizes the diverse roles played by surgical pathologists involved in clinical trials, with a special focus on quality assurance of diagnostic, laboratory, and reporting standards.