Reviews & Analysis

Various BRAF alterations are found and function as oncogenic drivers across diverse cancer types. BRAF inhibitor-based therapy has improved outcomes for patients with cancers harbouring BRAF^V600 mutations, although resistance develops in most, and the current inhibitors are not effective against other types of BRAF alterations. In this Review, the authors describe the mechanisms underlying oncogenic BRAF signalling, as well as pan-cancer and lineage-specific mechanisms of intrinsic, adaptive and acquired resistance to BRAF inhibitors. They also discuss novel RAF inhibitors and drug combinations designed to overcome these resistance mechanisms and/or expand the applicability of molecularly targeted therapy to a broader range of BRAF-mutant cancers.

Several novel personalized therapies focus on targeting neoantigens. Such strategies require the identification of suitable vaccine neoepitopes or neoantigen-specific T cell receptor (TCR) clonotypes. Herein, we discuss a recently published report that describes a combined transcriptional and phenotype signature, NeoTCR_PBL, that enables the minimally invasive identification of rare neoantigen-specific TCRs from peripheral blood that might enable more-effective T cell-based therapies against cancer.

Lung cancer is a disease typically associated with tobacco smoking; however, lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths globally. Moreover, smoking rates are declining around the world and therefore LCINS is likely to increase as a proportion of all lung cancers over time. Thus, understanding the aetiology and features of LCINS is increasingly important. Herein, the authors review the emerging data on the epidemiology, clinical characteristics and molecular features of LCINS as well as the genetic and environmental risk factors for this disease. They also summarize the unique diagnostic and management paradigms of LCINS.

Despite dramatic progress over the past decade, only around 50% of patients with advanced-stage melanoma derive durable benefit from immune-checkpoint inhibitors (ICIs) and/or BRAF and MEK (BRAF/MEK) inhibitors. Over the past few years, adoptive cell therapy with tumour-infiltrating lymphocytes (TILs) has demonstrated encouraging efficacy including in patients with disease progression on ICIs or BRAF/MEK inhibitors. In this Review, the authors summarize the role of TIL therapies in the management of these patients and describe future research strategies that might improve safety or efficacy.

Antibody–drug conjugates (ADCs) are effective cancer drugs that have been approved for more than 20 specific indications. Nonetheless, acquired resistance and adverse events both limit the effectiveness of these agents. In this Review, the authors describe the development of novel ADC designs, including bispecific ADCs, probody–drug conjugates, immune-stimulating ADCs, protein-degrader ADCs and dual-drug ADCs. all of which have the potential to address these challenges and provide more effective ADCs.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells that accumulate in the tumour microenvironment, where they exert various immunosuppressive mechanisms as well as a variety of other tumour-promoting effects. Herein, the authors provide an overview of MDSC generation and their accumulation in tumours, describe the interplay between MDSCs and various other cell types found in tumours, and review the mechanisms by which MDSCs promote tumour development and progression, metastasis, and resistance to treatment. They also discuss the effects of established treatment modalities on MDSCs as well as implications for the development of novel therapeutic strategies targeting these cells.

The discovery of ERBB2 as a gene frequently amplified and/or overexpressed in breast cancers and of its product HER2 as a biomarker has spurred the development of various targeted therapies. As a result, the prognosis of patients with advanced-stage HER2-positive breast cancer has greatly improved in the past decades. The authors of this Review describe the development of the current treatment landscape for these patients and discuss how to address resistance to further improve outcomes.

Recent results from the phase III PHILA trial demonstrate a benefit in terms of progression-free survival derived from the addition of pyrotinib to first-line chemotherapy plus trastuzumab in patients with metastatic HER2-positive breast cancer. Dual HER2 blockade with pyrotinib and trastuzumab is an effective therapeutic strategy but might increase the risk of gastrointestinal toxicity; therefore, the risk-to-benefit ratio should be carefully evaluated.

p53, encoded by TP53, the commonest mutated gene in cancer, is an appealing target for systemic anticancer therapies including those designed to restore p53 function. Thus far, and despite promising preclinical data and several clinical trials, no p53-restoring systemic therapy has been approved for therapeutic use. Despite this limited success, several research efforts are ongoing. In this Review, the authors summarize the role of p53 in cancer with a focus on the complexity of p53 function and how this relates to clinical attempts to restore at least some of these functions.

Cyclin-dependent kinase (CDK) 4/6 inhibitors in combination with endocrine therapy have become the standard-of-care therapy for patients with advanced-stage hormone receptor-positive breast cancer. However, this success has created several challenges, such as the need to better understand resistance to these agents and develop novel therapies accordingly. Here, the authors provide an update on the clinical activity of the established CDK4/6 inhibitors along with a summary of ongoing research efforts attempting to address the new challenges created by the success of these agents.

Recent results from the FLAURA2 and MARIPOSA-2 trials underline the continued role of chemotherapy in the treatment of patients with EGFR-mutated non-small-cell lung cancer in the era of targeted therapies. Herein, we argue that the most appropriate and rational sequence and/or combination of therapies remains a matter of discussion.

The current standard-of-care adjuvant treatment for patients with colorectal cancer is chemotherapy selected on the basis of conventional histopathological staging criteria; however, the clinical benefit from these regimens is limited. The authors of this Perspective discuss strategies to minimize toxicity and monitor efficacy of these regimens, and propose new tools for disease staging that could enable more personalized treatment decisions.

Neoadjuvant cisplatin-based combination chemotherapy followed by radical cystectomy with pelvic lymphadenectomy is the current standard therapy for cisplatin-eligible patients with muscle-invasive bladder cancer (MIBC). A phase II trial testing treatment intensification by adding the immune-checkpoint inhibitor nivolumab to chemotherapy has yielded promising complete response rates, which suggests that bladder-preserving treatment could become attainable in selected patients. This trial heralds a new era in demonstrating the feasibility of bladder preservation for selected patients with MIBC.

Patients with advanced-stage urothelial cancer (aUC) continue to have poor long-term survival outcomes. However, developments in the past 5 years, most notably the availability of maintenance therapy with the anti-PD-1 antibody avelumab, are beginning to change this issue. In this Review, the authors provide an overview of the treatment of patients with aUC, including considerations of the various promising new therapeutic modalities and how they might improve clinical outcomes.

Identifying patients who are likely to benefit from immune-checkpoint inhibitors remains one of the major challenges in immunotherapy. Cancer immunogenomics is an emerging field that bridges genomics and immunology. The authors of this Review provide an overview of the computational approaches currently available to analyse bulk tissue and single-cell sequencing data from cancer, stromal and immune cells.

Despite some success in patients with certain B cell malignancies and relapsed and/or refractory multiple myeloma, studies testing chimeric antigen receptor (CAR) T cells in patients with advanced-stage solid tumours have been largely unsuccessful, with a few notable exceptions. In this Perspective, the author provides some possible reasons for the failures of most CAR T cell-based approaches and suggests strategies that might address some of these challenges.

Hepatocellular carcinoma (HCC) is among the most common causes of cancer-related death globally, and despite improvements in prevention and treatment strategies, continued increases in HCC incidence and mortality are predicted. Cirrhosis remains the major risk factor for HCC, although the underlying aetiology is shifting from virus-related to non-viral liver diseases. In this Review, the authors discuss the changing trends in HCC epidemiology and their implications for screening, prevention and therapy, including opportunities to further improve the management of patients with, or at high risk of, HCC.

PRO-TECT is a randomized trial that innovatively integrated financial toxicity screening into a pre-existing digital symptom-monitoring programme, enabling longitudinal detection of financial toxicity. Such a strategy provides an unobtrusive and cost-effective method for early detection and mitigation of financial toxicity by aligning the needs of patients and carers with the resources available in community clinical practices.

According to the precision oncology paradigm, cancer therapies are increasingly being matched to specific sensitizing alterations using a biomarker-directed approach. However, the criteria for determining the actionability of molecular alterations and selecting matched treatments evolve over time. Molecular tumour boards (MTBs) have emerged as means to capitalize on the collective knowledge of various experts to interpret molecular-profiling data and to eliminate subjectivity in treatment selection. This Review describes the components, processes and increasingly important role of MTBs in optimizing the implementation of precision oncology in both clinical trials and clinical practice, as well as current and future considerations for ensuring the sustainability of MTBs and expanding their outreach to underserved populations.

The use of composite end points in clinical trials can expedite drug development and approval, and thus improve patient access to novel treatments, but are often vaguely and heterogeneously defined, with considerable inter-study variation in the component events that are included. The different component events can vary in clinical significance and be differentially affected by treatment but, nevertheless, are rarely reported separately. In this Perspective, Walia et al. define composite outcomes that are commonly used in oncology, discuss the advantages and challenges of using composite end points, and advocate for transparent reporting including a full breakdown of the component events to facilitate accurate interpretation of trial results and the true benefit of an intervention.