Future directions in the evaluation of c-MET-driven malignancies

Overcoming resistance to targeted therapy using MET inhibitors in solid cancers: evidence from preclinical and clinical studies

Targeted therapy is a hallmark of cancer treatment that has changed the landscape of cancer management and enabled a personalized treatment approach. Nevertheless, the development of cancer resistance is a major challenge that is currently threatening the effective utilization of targeted therapies. The hepatocyte growth factor receptor, MET, is a receptor tyrosine kinase known for its oncogenic activity and tumorigenic potential. MET is a well-known driver of cancer resistance. A growing body of evidence revealed a major role of MET in mediating acquired resistance to several classes of targeted therapies. Deregulations of MET commonly associated with the development of cancer resistance include gene amplification, overexpression, autocrine activation, and crosstalk with other signaling pathways. Small-molecule tyrosine kinase inhibitors of MET are currently approved for the treatment of different solid cancers. This review summarizes the current evidence regarding MET-mediated cancer resistance toward targeted therapies. The molecular mechanisms associated with resistance are described along with findings from preclinical and clinical studies on using MET inhibitors to restore the anticancer activity of targeted therapies for the treatment of solid tumors.

Current Concepts in Non-Gastrointestinal Stromal Tumor Soft Tissue Sarcomas: A Primer for Radiologists

Non-gastrointestinal stromal tumor (GIST) soft tissue sarcomas (STSs) are a heterogeneous group of neoplasms whose classification and management continues to evolve with better understanding of their biologic behavior. The 2013 World Health Organization (WHO) has revised their classification based on new immunohistochemical and cytogenetic data. In this article, we will provide a brief overview of the revised WHO classification of soft tissue tumors, discuss in detail the radiology and management of the two most common adult non-GIST STS, namely liposarcoma and leiomyosarcoma, and review some of the emerging histology-driven targeted therapies in non-GIST STS, focusing on the role of the radiologist.

MET inhibition in lung cancer

Targeted agents have completely changed cancer treatment strategy, leading it from a "one size fits all" approach to a customized therapy. In this scenario Met, a heterodimere receptor tyrosine kinase deeply involved into embryogenesis and organogenesis, has been introduced many years ago as a potential target for biological agents, becoming "druggable" only in this last period of time. Met can be altered through receptor overexpression, genomic amplification, mutations or alternative splicing, autocrine or paracrine secretion of hepatic growth factor (HGF): these dysregulations stimulate tumorigenesis (in terms of cell-cell detachment, proliferation, invasion, angiogenesis and survival) and metastatization. Met is overexpressed in lung cancer and Met gene amplification can drive the dependency of cell survival and proliferation upon the Met signaling. Both Met overexpression and amplification seem to correlate with poor prognosis. Met amplification is also described to be linked to EGFR acquired resistance. Several Met inhibitors have been tested both in preclinical and human trials, demonstrating activity in lung cancer treatment. This paper aims to summarize data on Met biological function, on its interaction with cell signaling and other pathways and to present data on those Met inhibitors currently under evaluation.