Systemic treatment in EGFR-ALK NSCLC patients:second line therapy and beyond

Lung cancer is the most frequently diagnosed cancer and a leading cause of cancer mortality worldwide, with adenocarcinoma being the most common histological subtype. Deeper understanding of the pathobiology of non-small cell lung cancer(NSCLC) has led to the development of small molecules that target genetic mutations known to play critical roles in progression to metastatic disease and to influence response to targeted therapies. The principle goal of precision medicine is to define those patient populations most likely to respond to targeted therapies. However, the cancer genome landscape is composed of relatively few "mountains" [representing the most commonly mutated genes like KRAS, epidermal growth factor(EGFR), and anaplastic lymphoma kinase(ALK)] and a vast number of "hills"(representing low frequency but potentially actionable mutations). Low-frequency lesions that affect a druggable gene product allow a relatively small population of cancer patients for targeted therapy to be selected.

Exploiting the potential of the ubiquitin-proteasome system in overcoming tyrosine kinase inhibitor resistance in chronic myeloid leukemia

The advent of tyrosine kinase inhibitors(TKI)targeting BCR-ABL has drastically changed the treatment approach of chronic myeloid leukemia(CML),greatly prolonged the life of CML patients,and improved their prognosis.However,TKI resistance is still a major problem with CML patients,reducing the efficacy of treatment and their quality of life.TKI resistance is mainly divided into BCR-ABL-dependent and BCR-ABL-independent resistance.Now,the main clinical strategy addressing TKI resistance is to switch to newly developed TKIs.However,data have shown that these new drugs may cause serious adverse reactions and intolerance and cannot address all resistance mutations.Therefore,finding new therapeutic targets to overcome TKI resistance is crucial and the ubiquitin-proteasome system(UPS)has emerged as a focus.The UPS mediates the degradation of most proteins in organisms and controls a wide range of physiological processes.In recent years,the study of UPS in hematological malignant tumors has resulted in effective treatments,such as bortezomib in the treatment of multiple myeloma and mantle cell lymphoma.In CML,the components of UPS cooperate or antagonize the efficacy of TKI by directly or indirectly affecting the ubiquitination of BCR-ABL,interfering with CML-related signaling pathways,and negatively or positively affecting leukemia stem cells.Some of these molecules may help overcome TKI resistance and treat CML.In this review,the mechanism of TKI resistance is briefly described,the components of UPS are introduced,existing studies on UPS participating in TKI resistance are listed,and UPS as the therapeutic target and strategies are discussed.