Pituitary tumors,
adenomas in their vast majority, represent around 10-15% of the
intracranial neoplasms.
Pituitary carcinomas are exceedingly rare. Clinically, these
neoplasms cause hormonal dysfunctions, and mass effect symptoms as
headache and
visual disorders in the case of macroadenomas. Pituitary
tumorigenesis is still poorly understood. In order to investigate the expression of
cancer-related genes in
pituitary tumors, we employed a human
cancer cDNA macroarray membrane with 1176 well-characterized human genes related to
cancer and
tumor biology. We were able to identify several differentially expressed genes, among them
hepatocyte growth factor-regulated tyrosine kinase substrate (HGS) and
guanylate kinase 1 (GUK1) which were over expressed in a pool of clinically nonfunctioning
pituitary adenomas, compared with a spinal cord
metastasis of a nonfunctioning
pituitary carcinoma. HGS and GUK1
mRNA expression were chosen to be validated by quantitative RT-qPCR, however, only GUK1 had the differential expression confirmed between the
adenomas and the
metastasis of a
pituitary carcinoma. We have also investigated HGS and GUK1
mRNA expressions in a series of 46
pituitary adenomas (18 nonfunctioning, 12 GH-secreting, nine PRL-secreting, and seven
ACTH-secreting
adenomas). HGS and GUK1 were significantly over expressed in GH-secreting
adenomas, compared with
ACTH-secreting
adenomas and nonfunctioning
tumors, and with PRL-secreting
adenomas, respectively. We have shown that these genes, involved in
tumorigenesis in other tissues, are as well over expressed in the
pituitary tumors, however, their role in the
oncogenesis of these
tumors need to be further investigated.