Expression of cholecystokinin forms by medullary thyroid cancer

Objective: The cholecystokinin 2 -receptor (CCK 2 R) promotes secretion and cell growth induced by its ligands cholecystokinin (CCK) and gastrin. The receptor has recently been shown to be expressed in human medullary thyroid carcinomas (MTCs). The objective of this study was to analyze CCK 2 R expression in MTC samples of different tumor stages as well as in non-malignant thyroid tissues. Design and Methods: Using RT-PCR we investigated 19 MTC samples and TT-cells (a human MTC cell line), as well as samples of normal thyroid. In addition, we performed immunohistochemistry using calcitonin-and CCK 2 R-specific antibodies on MTCs and samples of C-cell hyperplasia. Results: We demonstrate for the first time that CCK 2 R is expressed not only in MTCs but in all samples of normal thyroid tissue. Using immunohistochemistry the receptor could be localized on calcitoninsecreting C-cells. The highest incidence of CCK 2 R expression in MTCs was observed in early-tumor stages, whereas CCK 2 R could not be detected in advanced or metastasized tumors. Conclusions: The expression of CCK 2 R in C-cells suggests a physiological function for gastrin and/or CCK in the regulation of calcitonin release, presumably related to bone and calcium metabolism. Moreover, these ligands might act as growth factors in MTCs. Efforts in the development of CCK 2 R scintigraphy for the detection of MTC lesions might have to consider a lower incidence of the receptor in advanced tumor stages.

show abstract

“…1c). CCK has been identified as a secretory product of rat MTC cells (41,42). It is not known whether CCK is expressed in normal rat thyroid.…”

Section: Immunohistochemistrymentioning

confidence: 99%

Expression of the cholecystokinin 2-receptor in normal human thyroid gland and medullary thyroid carcinoma

Bläker

Weerth

Tometten

et al. 2002

European Journal of Endocrinology

View full text Add to dashboard Cite

show abstract

Peptide radiopharmaceuticals for diagnosis and therapy

Signore

Annovazzi

Chianelli

et al. 2001

European Journal of Nuclear Medicine and Molecular Imaging

View full text Add to dashboard Cite

Radiolabelled peptides are an emerging class of radiopharmaceuticals that share chemical and biological properties. From the chemical point of view they have a poly-amino acid structure varying from 3 to more that 200 amino acids, and they are labelled with different isotopes directly or by a linker. Biologically, they bind to specific cell membrane receptors, thus providing in vivo histopathological information for diagnostic purposes, therapy follow-up or targeted radiotherapy. This paper reviews most of the radiolabelled peptides that have been tested in animals and humans in the fields of oncology, neurology, cardiology, inflammation/infection, atherosclerosis and thrombosis. A new classification is also proposed for peptides targeting tumour cells based on the biological function of target receptors. These tailored radiopharmaceuticals are the basis of the new era of "molecular nuclear medicine".

show abstract