Pitfalls in molecular diagnostics.

Molecular diagnostic techniques are part of the ancillary arsenal of anatomic pathologists. Advances in technology and knowledge regarding disease pathogenesis, tumorigenesis, and immune function contribute to the development of these assays. However, each technique, if applied incorrectly or in ignorance, can lead to difficulties in execution or errors in interpretation. In this review of commonly used molecular diagnostic tests, including immunohistochemistry, microsatellite instability testing, chromosomal microarray testing, and conventional and next-generation sequencing, the emphasis will be on potential pitfalls and considerations for each platform. Emerging technologies that may be used in clinical applications in the near future will also be discussed. An understanding of the methodologies, advantages, and drawbacks of molecular assays will help pathologists aid in diagnostic and therapeutic decisions.