Aurora kinase A gene copy number is associated with the malignant transformation of colorectal adenomas but not with the serrated neoplasia progression

A crucial role for Aurora Kinase A (AURKA) gene has been demonstrated in the advanced steps of colorectal tumor progression. Little is known, however, about its role in the early phases of the adenoma-carcinoma sequence. Moreover, no data are currently available concerning AURKA involvement in the serrated tumorigenesis. Fluorescence in situ hybridization analysis and immunohistochemistry were used to assess gene copy number and protein expression in 40 colorectal adenomas, 20 cancerized adenomas, and 20 serrated polyps. An increased copy number was found either in adenomatous tissue or in early cancer in the vast majority of cancerized adenomas, but only in 5% of adenomas (P < .001). Protein expression strictly paralleled fluorescence in situ hybridization results. No changes in the gene copy number were observed in serrated polyps, regardless of their histotype and the presence of dysplasia, even if high percentages of immunostained cells were detected in all the subgroups. AURKA gene is associated with progressive colorectal adenomas but is uninvolved in the development of nonprogressive adenomas. The diploid status of the gene is maintained along the progression of serrated neoplasia. AURKA protein expression in serrated polyps is uncoupled from gene status and is likely to reflect apoptotic dysregulation. (C) 2015 Elsevier Inc. All rights reserved.