Somatostatin Receptor Imaging PET in Neuroendocrine Neoplasm

Positron emission tomography in the diagnosis and management of primary pediatric lung tumors

Primary pediatric lung tumors are uncommon and have many overlapping clinical and imaging features. In contrast to adult lung tumors, these rare pediatric neoplasms have a relatively broad histologic spectrum. Informed by a single-institution 13-year retrospective record review, we present an overview of the most common primary pediatric lung neoplasms, with a focus on the role of positron emission tomography (PET), specifically 18F-fluorodeoxyglucose (FDG) PET and 68Ga-DOTATATE PET, in the management of primary pediatric lung tumors. In addition to characteristic conventional radiographic and cross-sectional imaging findings, knowledge of patient age, underlying cancer predisposition syndromes, and PET imaging features may help narrow the differential. While metastases from other primary malignancies remain the most commonly encountered pediatric lung malignancy, the examples presented in this pictorial essay highlight many of the important conventional radiologic and PET imaging features of primary pediatric lung malignancies.

NEUROENDOCRINE PEPTIDES IN THE PATHOGENESIS OF COLORECTAL CARCINOMA

Colorectal carcinoma (CRC) is the third most frequent neoplasm worldwide and the second leading cause of mortality. Neuroendocrine peptides such as glucagon, bombesin, somatostatin, cholecystokinin, and gastrin as well as growth factors such as platelet-derived growth factor, epidermal growth factor, insulin-like growth factor, and fibroblast growth factor have been postulated as being involved in carcinogenesis. The fact that these neuroendocrine peptides are involved in the development of CRC through the activation of growth factors that stimulate a series of molecular pathways that activate oncogenic signaling mechanisms is emphasized in this review. Peptides such as CCK1, serotonin, and bombesin have been found to be over-expressed in human tumor tissues. Meanwhile, the expression of peptides such as GLP2 has been seen mainly in murine models. The information contained in this review provides a better understanding of the role these peptides play in the pathogenesis of CRC for basic and clinical science studies.

Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy

G-protein-coupled receptors (GPCRs) are increasingly being considered as possible therapeutic targets in cancers. Activation of GPCR on tumors can have prominent growth effects, and GPCRs are frequently over-/ectopically expressed on tumors and thus can be used for targeted therapy. CNS/neural tumors are receiving increasing attention using this approach. Gliomas are the most frequent primary malignant brain/CNS tumor with glioblastoma having a 10-year survival <1%; neuroblastomas are the most common extracranial solid tumor in children with long-term survival<40%, and medulloblastomas are less common, but one subgroup has a 5-year survival <60%. Thus, there is an increased need for more effective treatments of these tumors. The Bombesin-receptor family (BnRs) is one of the GPCRs that are most frequently over/ectopically expressed by common tumors and is receiving particular attention as a possible therapeutic target in several tumors, particularly in prostate, breast, and lung cancer. We review in this paper evidence suggesting why a similar approach in some CNS/neural tumors (gliomas, neuroblastomas, medulloblastomas) should also be considered.