In the current study we report the cloning, amplification in bacteria, and sequence analysis of DNA complementary to Prl mRNA isolated from human pituitary Prl-secreting adenomas.
The role of the intraluminal environment and the mechanisms of its interaction with the mucosa appear to be important areas for research directed at the pathogenesis of adenomas in FPC, due to the implications for therapy.
Altered proopiomelanocortin gene expression in adrenocorticotropin-producing nonpituitary tumors. Comparative studies with corticotropic adenomas and normal pituitaries.
We have found that the expression of p53 messenger RNA is growth regulated in human cells following kinetics similar to that previously shown in mouse 3T3 cells, and is increased in the large majority of colon adenocarcinomas in comparison to adjacent normal mucosa and adenoma.
These results demonstrate that the flat mucosa of patients with familial polyposis coli shows preneoplastic changes similar to those in the mucosa adjacent to carcinoma of sporadic cases, and that SSEA-1 is related to adenoma formation in the early stage of carcinogenesis in the colorectum.
Hybridization experiments were performed between dot-blotted mRNA originating either from placenta or from one pituitary hGH secreting adenoma and synthetic polynucleotide probes corresponding to specific portions of the hGH-V or hGH-N gene sequences.
Thus, the enhanced expression of c-myc gene in adenoma and carcinoma may reflect the proliferative activity, while the c-fos gene may be a prerequisite to stabilize the state of terminal differentiation of colonic epithelial cells.
Thus, the enhanced expression of c-myc gene in adenoma and carcinoma may reflect the proliferative activity, while the c-fos gene may be a prerequisite to stabilize the state of terminal differentiation of colonic epithelial cells.
Expression of the SRIH gene was investigated in six human normal anterior pituitaries, six GH-, three PRL-, three mixed GH/PRL-secreting and four nonsecreting adenomas.
The fact that abnormalities of calcitonin gene methylation are less frequent in DNA from human colonic carcinomas than from adenomas and colon carcinoma cell culture lines is of special interest.
Thus, the study of PRL gene expression and immunohistochemistry in GH-secreting adenomas is valuable to understanding the pathophysiology of pituitary tumors.
These results suggest the following mechanisms for the development of colon tumors in patients with familial adenomatous polyposis: (a) the heterozygous mutant/wild-type condition at the APC gene causes formation of mild or moderate adenoma; (b) the loss of the normal allele in the APC gene leads to a change from moderate to severe adenoma; (c) LOH on chromosome 17p contributes to the conversion of adenoma to intramucosal carcinoma; (d) LOH on other chromosomes, such as 18 and 22q, are involved in the progression of intramucosal carcinoma to invasive carcinoma; and (e) K-ras mutation may also affect the development of moderate to severe adenoma.
In colorectal carcinoma, it has been shown that the accumulation of several alterations in ras genes and p53 genes is most important for the conversion of adenoma to carcinoma.
We studied the effects of GnRH, CRF, dexamethasone, and phorbol 12-myristate 13-acetate on FSH and LH secretion and on FSH beta and chromogranin-A and -B mRNA expression in 10 chromogranin-A-positive adenomas in vitro to analyze the regulation of FSH and chromogranin-A and -B expression in these neoplasms.
Hybridization was clearly detected throughout the cytoplasm of 7 out of 15 adenomas and 13 out of 15 carcinomas with the CEA cDNA probe, and in 6 out of 15 adenomas and 10 out of 15 carcinomas with the NCA cDNA probe.
These results indicate that subtype 1 silent adenomas and clinically active adenomas associated with Cushing's disease contain POMC mRNA that is readily detectable by ISH in routinely processed tissue specimens, while only a few of the subtypes 2 and 3 adenomas have POMC mRNA that can be detected in paraffin blocks with the oligonucleotide probes used in this study.
All adenomas (4 prolactinomas, 3 growth hormone (GH) producing adenomas and 4 inactive adenomas) showed SYN and NSE immunoreactivity on tissue sections and this was confirmed by immunoblots.
Thus, the study of PRL gene expression and immunohistochemistry in GH-secreting adenomas is valuable to understanding the pathophysiology of pituitary tumors.