Molecular lung cancer: How targeted therapies and personalized medicine are re-defining cancer care.

Lung cancer remains the leading cause of cancer death in the United States and is unfortunately still frequently diagnosed in the metastatic setting, where the disease is considered incurable. Nearly 30% of these cancers may be driven by specific mutations that promote tumor growth and proliferation. These mutations are observed more frequently in young patients without significant smoking history and in certain racial and ethnic backgrounds. The past 15 years have marked a revolution for patients with molecularly driven lung cancer as novel, oral, targeted therapies have been developed that demonstrate superior activity with substantially better toxicity profiles in comparison to chemotherapy. Consideration of molecular testing for a driver mutation is imperative for all providers caring for patients with a new suspected lung cancer diagnosis, as discovery of an actionable mutation will have dramatic implications in regards to patient survival and quality of life.

Primary Dural Diffuse Large B-cell Lymphoma: A Comprehensive Review of Survival and Treatment Outcomes.

Primary dural diffuse large B-cell lymphoma (PD-DLBCL) is a rare and aggressive B-cell non-Hodgkin lymphoma that can present in intracranial or intraspinal locations. Although the optimal management is unknown, PD-DLBCL therapy is often mirrored after primary central nervous system lymphoma therapy and aggressive treatment with a high dose methotrexate-based regimen is frequently used. Our comprehensive, retrospective study of 24 reported cases of PD-DLBCL provide the most complete analysis of this rare disease including data on biology, treatment outcomes, and survival. Our findings demonstrate good outcomes following induction treatment with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone), suggesting that these cases can be treated as DLBCL rather than primary central nervous system lymphoma, obviating the need for more aggressive and toxic approaches. The durable responses following R-CHOP also confirm that PD-DLBCL is not protected by the blood brain barrier.

Dysregulated mTORC1 renders cells critically dependent on desaturated lipids for survival under tumor-like stress.

Solid tumors exhibit heterogeneous microenvironments, often characterized by limiting concentrations of oxygen (O2), glucose, and other nutrients. How oncogenic mutations alter stress response pathways, metabolism, and cell survival in the face of these challenges is incompletely understood. Here we report that constitutive mammalian target of rapamycin complex 1 (mTORC1) activity renders hypoxic cells dependent on exogenous desaturated lipids, as levels of de novo synthesized unsaturated fatty acids are reduced under low O2. Specifically, we demonstrate that hypoxic Tsc2(-/-) (tuberous sclerosis complex 2(-/-)) cells deprived of serum lipids exhibit a magnified unfolded protein response (UPR) but fail to appropriately expand their endoplasmic reticulum (ER), leading to inositol-requiring protein-1 (IRE1)-dependent cell death that can be reversed by the addition of unsaturated lipids. UPR activation and apoptosis were also detected in Tsc2-deficient kidney tumors. Importantly, we observed this phenotype in multiple human cancer cell lines and suggest that cells committed to unregulated growth within ischemic tumor microenvironments are unable to balance lipid and protein synthesis due to a critical limitation in desaturated lipids.

Endothelial HIF-2α regulates murine pathological angiogenesis and revascularization processes.

Localized tissue hypoxia is a consequence of vascular compromise or rapid cellular proliferation and is a potent inducer of compensatory angiogenesis. The oxygen-responsive transcriptional regulator hypoxia-inducible factor 2α (HIF-2α) is highly expressed in vascular ECs and, along with HIF-1α, activates expression of target genes whose products modulate vascular functions and angiogenesis. However, the mechanisms by which HIF-2α regulates EC function and tissue perfusion under physiological and pathological conditions are poorly understood. Using mice in which Hif2a was specifically deleted in ECs, we demonstrate here that HIF-2α expression is required for angiogenic responses during hindlimb ischemia and for the growth of autochthonous skin tumors. EC-specific Hif2a deletion resulted in increased vessel formation in both models; however, these vessels failed to undergo proper arteriogenesis, resulting in poor perfusion. Analysis of cultured HIF-2α-deficient ECs revealed cell-autonomous increases in migration, invasion, and morphogenetic activity, which correlated with HIF-2α-dependent expression of specific angiogenic factors, including delta-like ligand 4 (Dll4), a Notch ligand, and angiopoietin 2. By stimulating Dll4 signaling in cultured ECs or restoring Dll4 expression in ischemic muscle tissue, we rescued most of the HIF-2α-dependent EC phenotypes in vitro and in vivo, emphasizing the critical role of Dll4/Notch signaling as a downstream target of HIF-2α in ECs. These results indicate that HIF-1α and HIF-2α fulfill complementary, but largely nonoverlapping, essential functions in pathophysiological angiogenesis.