Genomic instability in non-functioning pituitary adenomas

Non-functioning pituitary adenomas have no hormone immunoreactivity, and no other immunohistochemical or ultrastructural markers of specific adenohypophysial cell differentiation. Because only few studies describe cytogenetic changes in non-functioning pituitary adenomas, we studied the spectrum of chromosomal imbalances associated, using comparative genomic hybridization (CGH). Copy number aberrations on all 22 autosomes were evaluated by CGH using advanced computer software. In total, ten patients with non-functioning pituitary adenomas were included in the study. Average sum of imbalances in this group was 22.7±11.8. Average number of gains was 8,0±7.8 whereas number of losses was 14.7±10.1. The typical changes of this group were losses of chromosomes 5q, 14q, 4q, 6q and gains on chromosome 9q. The histogram indicated the highest frequency of changes for the losses were on –5q22–3, -14q31 (7/10) –4q21, -4q24, -4q24–6, -6q14 (6/10) and for gains +9q21 (6/10). Average number of changes in nonfunctioning adenomas was lower than in functioning once. Our analysis of chromosome abnormalities in non-functioning pituitary adenoma will contribute to our knowledge of this group of neoplasm.