Microarray Gene Expression in Pterygia

Abstract

Abstract: : Purpose: We have previously described two types of tumors in pterygia: A) The pterygium tumor of invading altered limbal epithelial basal stem cells; and B) the pinguecula tumor of stationary non-invading altered fibroblasts. The purpose of this study was to find the gene expression profile of whole pterygia using DNA microarray technology. Methods: Thirteen primary and one recurrent pterygia and normal residual superior limbal conjunctival graft tissue were surgically removed and immediately frozen or placed in a solution of RNA later. The Affymetrix human U95AV2 gene chip was used to investigate 12,000 genes. Hybridization signals were normalized, filtered, and data analyzed using Gene Spring Analysis Software (Silicon Genetics CA, USA). Results: Three pterygia, one recurrent and two primary, were found suitable for individual microarray testing. We found 41 genes that had a statistically significant (Welsh t-test) change. Upregulation occurred in the following gene categories: collagen (2), extracellular matrix (2), extracellular matrix protein precursor (1) and oncogenes (2). Down regulation was found in the following gene catagories: cell cycle related (1), collagen (2), extracellular matrix (1), and oncogenes (3). Prominent among the regulated genes were: fibronectin, collagen III, and protein tyrosine phosphatase. P53 was found to be at normal levels. Conclusions: DNA microarray technology is useful in studying the genetic changes in pterygia. These studies suggest specific sites of gene regulation that are involved in the growth and migration of pterygia, which could potentially be translated into a clinical treatment for pterygia using gene therapy. It should be noted that these pterygia contained both fibroblasts and epithelial cells.

Keywords: gene microarray • cornea: basic science • gene/expression