MicroRNAs (
miRNAs) are involved in cell proliferation, differentiation, and apoptosis, and can function as tumor suppressor genes or oncogenes. The expression of
miRNAs in
pituitary carcinomas has not been previously examined. We used
miRNA profiling with 1,145 probes to study
miRNA expression in normal anterior pituitary (6 cases),
adrenocorticotropin (
ACTH)-producing
adenomas (8 cases), and
ACTH-producing
pituitary carcinomas (two cases). Real-time RT-PCR and in situ hybridization were used to confirm and independently validate
miRNAs that were significantly up-regulated or down-regulated between the pituitary tissues. There were more
miRNAs up- (188) or down-regulated (160) between
adenomas and normal pituitaries compared to
carcinomas and normal pituitaries (92 up- and 91 down-regulated) or between
carcinomas and
adenomas (46 up- and 52 down-regulated). Both real-time RT-PCR and in situ hybridization showed significant up-regulation of miRNA-122 between
pituitary carcinomas and
adenomas. MiRNA-493 was also up-regulated in
carcinomas compared to
ACTH adenomas. Analysis of genes that miRNA-493 interacts with included
LGALS3 and RUNX2 ( http://
microrna.sanger.ac.uk ) both of which have been shown to have roles in
pituitary tumor cell growth. These results provide information about marker
miRNAs that may lead to further insights into the regulation of
pituitary tumor growth and development.