Traditional cytogenetic techniques for the macro-analysis of chromosomal structure often preclude high-resolution visualization of specific genomic regions. Accordingly, researchers are increasingly turning to molecular cytogenetic tools, including fluorescence in situ hybridization (FISH) and arrays, for enhanced association studies, gene discovery, gene mapping, complex disease trait analyses, and improved diagnostic capabilities. The growing need for molecular cytogenetics tools has resulted in a rapidly evolving market where vendors’ product portfolios are quickly expanding to enable continued discovery and simplified data interpretation.
Currently, the greatest driver of molecular cytogenetics market growth is coming from the sales of array-based technologies for comparative genomic hybridization (CGH). In 2008, the U.S. array-based molecular cytogenetics market was estimated at $41.7 million; approximately one-third of the total U.S. molecular cytogenetics market.
Array-based CGH, or aCGH, is comparable to performing hundreds or thousands of FISH experiments in one array, and is therefore analogous to a high-density FISH test. While novel technologies like next-generation sequencing and unique multiplex assay platforms are supplanting arrays for some genomics applications, aCGH has become researchers’ method-of-choice for molecular cytogenetics.
As a high-resolution tool, aCGH allows for the identification of specific genotypes that associate with particular phenotypes. Consequently, aCGH is increasingly employed for initial screening whereby aberrated areas of the genome are identified using arrays and then confirmed with a FISH probe. Moreover, aCGH eliminates the problem of “FISHing” for the aberrated areas since clinicians can avoid having to select tests based on sequential guessing.
The introduction of aCGH techniques has permitted the move from sequential diagnostics to parallel diagnostics, which means clinicians can order one test that provides an accurate diagnosis the first time around. Over the next couple of years, FISH is expected to become a tool to validate array data rather than serve as the primary technology. Given the platform’s suitability as a primary molecular cytogenetics technology, revenues from aCGH are expected to grow from one-third to more than half of the total U.S. molecular cytogenetics market by 2013.
The development of array-based technologies for molecular cytogenetics is most significant with regards to the convergence of molecular diagnostics and clinical cytogenetics. Because array-based molecular cytogenetic methods provide high-resolution copy number variation information, they are expected to impact multiple areas within medicine.
From 1999, when Jonathan Pollack et al. published the first paper on the use of the CGH array to provide full genome analysis of several cancer cell lines, until 2004, the tool was mainly used for research and was expected to remain so for many years to come. While an exciting tool, its emerging-technology status and intrinsic technological concerns in terms of reproducibility, accuracy, data interpretation, etc., did not foretell aCGH would be a tool for clinical applications.
However, the 2004 introduction of aCGH for clinical applications forced vendors to quickly shift their attention to targeting diagnostic laboratories. Since then, market competition has intensified for both array vendors and the laboratories offering academic or commercial services.
Vendors are currently executing aggressive product-development strategies focused on bringing new array-based molecular cytogenetics technologies to the clinical sector. These vendors are eager to tap into a largely unaddressed market where fewer than 20% of U.S. hospitals have implemented aCGH. Although many hospital laboratory managers are still waiting to see how testing evolves before adopting an array platform, their increased confidence in array data interpretation should play a major role in the forecasted 15.7% compound annual growth rate of the total U.S. molecular cytogenetics market between 2008 and 2015.