We've made significant changes to the structure of our commercial organization, and made a number of key hires, as well. This includes a new head of global commercial operations, Vice Presidents of both Global Marketing and Regulatory, as well as new commercial leadership in Europe and Japan. We're making a steady progress in redirecting the business and laying the groundwork for a return to growth.
For 2012, we are executing against the focus set of commercial goals that include: first, stabilizing our expression business. This includes arrays, low-plex solutions and single cell and tissue products. Increasing our -- secondly, increasing our market share in genotyping, particularly targeted applications. Third, building critical mass toward a market-leading position in cytogenetics. And last, driving continued growth on our life science reagents business.
I'd like to highlight some quarterly accomplishments and expectations against each of these initiatives, starting with our expression business unit. Expression constitutes about 45% of our revenue, and we took some important steps towards stabilizing the business in the fourth quarter.
One of our primary goals is to offset the decline in our IVT revenue. We intend to do this by adding new products to our array-based expression portfolio and rejuvenating our Panomics mid-plex cell and tissue assays. We anticipate that our overall expression business will decline by 5% to 10% in 2012. But we also see emerging opportunities that will help offset the decline of our IVT arrays. This is a significant challenge for us. As you're aware, we are focusing on the area with new products for preclinical and clinical applications.And I want to give you a short progress report on some of our activities in this area. We recently entered into an exclusive agreement with Genisphere to offer the company's FlashTag Biotin reagents. These microRNA reagents enables streamlined target prep methods for high-quality and reproducibility, and strengthen our industry-leading position in array-based gene expression. microRNA is one of the fastest growing applications in gene expression, and represents an important new revenue stream for Affymetrix, one that we expect will grow significantly, as we continue to introduce new content.