Hyperfunctioning thyroid adenoma and activating mutations in the TSH receptor gene

Objective assessment of cancer genes for drug discovery

Selecting the best targets is a key challenge for drug discovery, and achieving this effectively, efficiently and systematically is particularly important for prioritizing candidates from the sizeable lists of potential therapeutic targets that are now emerging from large-scale multi-omics initiatives, such as those in oncology. Here, we describe an objective, systematic, multifaceted computational assessment of biological and chemical space that can be applied to any human gene set to prioritize targets for therapeutic exploration. We use this approach to evaluate an exemplar set of 479 cancer-associated genes, reveal the tension between biological relevance and chemical tractability, and describe major gaps in available knowledge that could be addressed to aid objective decision-making. We also propose drug repurposing opportunities and identify potentially druggable cancer-associated proteins that have been poorly explored with regard to the discovery of small-molecule modulators, despite their biological relevance.

Pitfalls in the diagnosis of follicular epithelial proliferations of the thyroid

The diagnosis of follicular epithelial neoplasms is an area of controversy. We provide our experience with common problems that practising pathologists face when confronted with follicular epithelial proliferations. One of the major issues is the recognition of the diagnostic nuclear features of papillary thyroid carcinoma and reactive cytologic atypia. We discuss the definitions of capsular invasion, vascular invasion, and extrathyroidal extension and their implications in cancer diagnosis and staging. We propose unified terminology for benign follicular epithelial proliferations in the setting of multinodular goiter. We also review challenges related to oncocytic change, malignant transformation in benign nodules, focal dedifferentiation, and the application of ancillary tools in thyroid pathology. We believe that this review contains comprehensive and up to date information that will be of value to pathologists who practice surgical pathology of thyroid.

Essential role for the second extracellular loop in C5a receptor activation

More than 90% of G protein-coupled receptors (GPCRs) contain a disulfide bridge that tethers the second extracellular loop (EC2) to the third transmembrane helix. To determine the importance of EC2 and its disulfide bridge in receptor activation, we subjected this region of the complement factor 5a receptor (C5aR) to random saturation mutagenesis and screened for functional receptors in yeast. The cysteine forming the disulfide bridge was the only conserved residue in the EC2-mutated receptors. Notably, approximately 80% of the functional receptors exhibited potent constitutive activity. These results demonstrate an unexpected role for EC2 as a negative regulator of C5a receptor activation. We propose that in other GPCRs, EC2 might serve a similar role by stabilizing the inactive state of the receptor.

Genetic variations and polymorphisms of G protein-coupled receptors: functional and therapeutic implications

G protein-coupled receptors (GPCRs) represent a major class of proteins in the genome of many species, including humans. In addition to the mapping of a number of human disorders to regions of the genome containing GPCRs, a growing body of literature has documented frequently occurring variations (i.e. polymorphisms) in GPCR loci. In this article, we use a domain-based approach to systematically examine examples of genetic variation in the coding and noncoding regions of GPCR loci. Data to date indicate that residues in GPCRs are involved in ligand binding and coupling to G proteins and that regulation can be altered by polymorphisms. Studies of GPCR polymorphisms have also uncovered the functional importance of residues not previously implicated from other approaches that are involved in the function of GPCRs. We predict that studies of GPCR polymorphisms will have a significant impact on medicine and pharmacology, in particular, by providing new means to subclassify patients in terms of both diagnosis and treatment.