Relationship between genomic alterations at chr 11p15.5 and IGF2 gene expression in adrenocortical tumors.
A) Relative mRNA expression levels evaluated by qRT-PCR for IGF2 gene according to the copy number status observed with SNP array analysis in normal adrenals (n=16), adenomas (n=18) and carcinomas (n=14). The gene actin beta was used as a loading control (reference gene). Data expressed as logarithmic scale. P=0.0003 by one-way ANOVA.
B) Schematic representation of the genetic alterations at the 11p15.5 imprinted locus and their impact on IGF2 expression levels. In particular, we firstly report frequent copy number gains in adenomas, leading to a normal IGF2 expression, and we confirm frequent copy neutral LOH events in carcinoma, leading to an increased IGF2 expression, suggesting a progressive multi-step genetic derangement in this locus. We also demonstrate a further allele loss in carcinoma (LOH + CN loss) without effects on IGF2 expression.