Liquid biopsies hold the potential to inform cancer patient prognosis and to guide treatment decisions at the time when direct tumor biopsy may be impractical due to its invasive nature, ...inaccessibility and associated complications. Specifically, circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) have shown promising results as companion diagnostic biomarkers for screening, prognostication and/or patient surveillance in many cancer types. In ovarian cancer (OC), CTC and ctDNA analysis allow comprehensive molecular profiling of the primary, metastatic and recurrent tumors. These biomarkers also correlate with overall tumor burden and thus, they provide minimally-invasive means for patient monitoring during clinical course to ascertain therapy response and timely treatment modification in the context of disease relapse. Here, we review recent reports of the potential clinical value of CTC and ctDNA in OC, expatiating on their use in diagnosis and prognosis. We critically appraise the current evidence, and discuss the issues that still need to be addressed before liquid biopsies can be implemented in routine clinical practice for OC management.
•Standardisation of methodologies is required for thorough evaluation of the clinical utility of CTCs in ovarian cancer.•CTC holds key biological information for understanding the metastatic process.•ctDNA is a promising biomarker for early diagnosis and monitoring of ovarian cancer.•DNA methylation patterns in cell-free DNA have potential for early diagnosis of ovarian cancer.
Identifying the targets of broadly neutralizing antibodies to HIV-1 and understanding how these antibodies develop remain important goals in the quest to rationally develop an HIV-1 vaccine. We ...previously identified a participant in the CAPRISA Acute Infection Cohort (CAP257) whose plasma neutralized 84% of heterologous viruses. In this study we showed that breadth in CAP257 was largely due to the sequential, transient appearance of three distinct broadly neutralizing antibody specificities spanning the first 4.5 years of infection. The first specificity targeted an epitope in the V2 region of gp120 that was also recognized by strain-specific antibodies 7 weeks earlier. Specificity for the autologous virus was determined largely by a rare N167 antigenic variant of V2, with viral escape to the more common D167 immunotype coinciding with the development of the first wave of broadly neutralizing antibodies. Escape from these broadly neutralizing V2 antibodies through deletion of the glycan at N160 was associated with exposure of an epitope in the CD4 binding site that became the target for a second wave of broadly neutralizing antibodies. Neutralization by these CD4 binding site antibodies was almost entirely dependent on the glycan at position N276. Early viral escape mutations in the CD4 binding site drove an increase in wave two neutralization breadth, as this second wave of heterologous neutralization matured to recognize multiple immunotypes within this site. The third wave targeted a quaternary epitope that did not overlap any of the four known sites of vulnerability on the HIV-1 envelope and remains undefined. Altogether this study showed that the human immune system is capable of generating multiple broadly neutralizing antibodies in response to a constantly evolving viral population that exposes new targets as a consequence of escape from earlier neutralizing antibodies.
Circulating tumour DNA (ctDNA) has emerged as a promising blood-based biomarker for monitoring disease status of patients with advanced cancers. In melanoma, ctDNA has been shown to have clinical ...value as an alternative tumour source for the detection clinically targetable mutations for the assessment of response to therapy. This review provides a critical summary of the evidence that gives credence to the utility of ctDNA as a biomarker for monitoring of disease status in advanced melanoma and the steps required for its implementation into clinical settings.
•ctDNA as a biomarker of disease status in advanced melanoma.•ctDNA as an indicator of response to treatment.•ctDNA for monitoring clonal evolution and emergence of resistance.•Epigenetic changes in melanoma ctDNA.•The challenges associated with clinical implementation of ctDNA for melanoma management.
The introduction of targeted therapies for the treatment of BRAF-mutant melanomas have improved survival rates in a significant proportion of patients. Nonetheless, the emergence of resistance to ...treatment remains inevitable in most patients.
Here, we review known and emerging molecular mechanisms that underlay the development of resistance to MAPK inhibition in melanoma cells and the potential strategies to overcome these mechanisms.
Multiple genetic and non-genetic mechanisms contribute to treatment failure, commonly leading to the reactivation of the MAPK pathway. A variety of resistance mechanisms are enabled by the underlying heterogeneity and plasticity of melanoma cells. Moreover, it has become apparent that resistance to targeted therapy is underpinned by early functional adaptations involving the rewiring of cell states and metabolic pathways.
The evidence presented suggest that the use of a combinatorial treatment approach would delay the emergence of resistance and improve patient outcomes.
•Review of known and emerging molecular mechanisms that underlay the development of resistance to MAPK inhibition.•Resistance to targeted therapy is underpinned by early adaptations such as rewiring of cell states and metabolic pathways.•Discussion of potential strategies to overcome these mechanisms.•The use of a combinatorial treatment approach would delay the emergence of resistance and improve patient outcomes.
Broadly neutralizing antibodies are not commonly produced in HIV-1 infected individuals nor by experimental HIV-1 vaccines. When these antibodies do occur, it is important to be able to isolate and ...characterize them to provide clues for vaccine design. CAP206 is a South African subtype C HIV-1-infected individual previously shown to have broadly neutralizing plasma antibodies targeting the envelope gp41 distal membrane proximal external region (MPER). We have now used a fluoresceinated peptide tetramer antigen with specific cell sorting to isolate a human neutralizing monoclonal antibody (mAb) against the HIV-1 envelope gp41 MPER. The isolated recombinant mAb, CAP206-CH12, utilized a portion of the distal MPER (HXB2 amino acid residues, 673-680) and neutralized a subset of HIV-1 pseudoviruses sensitive to CAP206 plasma antibodies. Interestingly, this mAb was polyreactive and used the same germ-line variable heavy (V(H)1-69) and variable kappa light chain (V(K)3-20) gene families as the prototype broadly neutralizing anti-MPER mAb, 4E10 (residues 672-680). These data indicate that there are multiple immunogenic targets in the C-terminus of the MPER of HIV-1 gp41 envelope and suggests that gp41 neutralizing epitopes may interact with a restricted set of naive B cells during HIV-1 infection.
Biomarkers that predict the risk of immune-mediated adverse events (irAEs) among patients with non-small cell lung cancer (NSCLC) may reduce morbidity and mortality associated with these treatments.
...We carried out high resolution human leucocyte antigen (HLA)-I typing on 179 patients with NSCLC treated with anti-program death (PD)-1/program death ligand (PDL)-1. Toxicity data were collected and graded as per common terminology criteria for adverse event (CTCAE) v5.0. We used 14.8-week for landmark analysis to address lead-time bias to investigate the correlation between HLA-I/II zygosity, supertypes and alleles with irAE. Furthermore, we assessed the association for irAE with clinical benefit rate (CBR), progression-free survival (PFS) and overall survival (OS).
Homozygosity at one or more HLA-I loci, but not HLA-II, was associated with a reduced risk of irAE (relative risk (RR) = 0.61, 95% CI 0.33–0.95, P = 0.035) especially pneumonitis or any grade 3 toxicity. Patients with HLA-A03 supertype had a higher risk of developing irAE (RR = 1.42, 95% CI 1.02–2.01, P = 0.039). The occurrence of any irAE was significantly associated with improved CBR (RR = 1.48, P < 0.0001), PFS (HR = 0.45, P = 0.0003) and OS (HR = 0.34, P < 0.0001).
Homozygosity at one or more HLA-I loci may serve as biomarker to predict patients who are unlikely to experience severe irAEs among patients with NSCLC and treated with anti-PD1/PDL1, but less likely to derive clinical benefit. Patients with HLA-I homozygous might benefit from additional therapy.
•Homozygosity at ≥1 human ligand antigen (HLA)-I loci is associated with a reduced risk of immune-related adverse effect (irAE).•Homozygosity at ≥1 HLA-I loci protective against pneumonitis or grade 3 toxicity.•HLA-A3 supertype is associated with an increased risk of irAE.•The occurrence irAE is associated with improved clinical outcomes and survival.
Plasma circulating tumour DNA (ctDNA) has been suggested to be a viable biomarker of response to treatment in patients with high grade serous ovarian carcinoma (HGSOC). TP53 mutations are present in ...more than 90% of HGSOCs but somatic variants are distributed across all exonic regions of the gene, requiring next generation sequencing (NGS) technologies for mutational analysis. In this study, we compared the suitability of the Accel (Swift) and Oncomine (ThermoFisher) panels for identification of TP53 mutations in ctDNA of HGSOC patients (N = 10). Only 6 patients (60%) were found to have TP53 mutations using the ACCEL panel but the addition of molecular tags in the Oncomine panel improved ctDNA detection with at least one mutation detected in all cases (100%). Orthogonal validation of the 14 somatic variants found by Oncomine, using droplet digital PCR, confirmed 79% (11/14) of the identified mutations. Overall, the Oncomine panel with unique molecular identifiers (UMI) appears more useful for ctDNA analysis in HGSOC.
Antibodies against programmed death-1 (PD-1), and its ligand, (PD-L1) have been approved recently for the treatment of small-cell lung cancer (SCLC). Although there are previous reports that ...addressed PD-L1 detection on tumour cells in SCLC, there is no comprehensive meta-analysis on the prevalence of PD-L1 expression in SCLC. We performed a systematic search of the PubMed, Cochrane Library and EMBASE databases to assess reports on the prevalence of PD-L1 expression and the association between PD-L1 expression and overall survival (OS). This meta-analysis included 27 studies enrolling a total of 2792 patients. The pooled estimate of PD-L1 expression was 26.0% (95% CI 17.0-37.0), (22.0% after removing outlying studies). The effect size was significantly heterogeneous (I
= 97.4, 95% CI: 95.5-98.5,
< 0.0001).Positive PD-L1 expression was a favourable prognostic factor for SCLC but not statistically significant (HR = 0.86 (95% CI (0.49-1.50),
= 0.5880; I
= 88.7%,
< 0.0001). Begg's funnel plots and Egger's tests indicated no publication bias across included studies (
> 0.05). Overall, there is heterogeneity in the prevalence of PD-L1 expression in SCLC tumour cells across studies. This is significantly moderated by factors such as immunohistochemistry (IHC) evaluation cut-off values, and assessment of PD-L1 staining patterns as membranous and/or cytoplasmic. There is the need for large size, prospective and multicentre studies with well-defined protocols and endpoints to advance the clinical value of PD-L1 expression in SCLC.
Uveal melanoma (UM) is the most common primary intraocular malignancy affecting adults. Despite successful local treatment of the primary tumour, metastatic disease develops in up to 50% of patients. ...Metastatic UM carries a particularly poor prognosis, with no effective therapeutic option available to date. Genetic studies of UM have demonstrated that cytogenetic features, including gene expression, somatic copy number alterations and specific gene mutations can allow more accurate assessment of metastatic risk. Pre-emptive therapies to avert metastasis are being tested in clinical trials in patients with high-risk UM. However, current prognostic methods require an intraocular tumour biopsy, which is a highly invasive procedure carrying a risk of vision-threatening complications and is limited by sampling variability. Recently, a new diagnostic concept known as "liquid biopsy" has emerged, heralding a substantial potential for minimally invasive genetic characterisation of tumours. Here, we examine the current evidence supporting the potential of blood circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), microRNA (miRNA) and exosomes as biomarkers for UM. In particular, we discuss the potential of these biomarkers to aid clinical decision making throughout the management of UM patients.
Circulating tumor cells (CTCs) are cancer cells shed by the primary tumor or its metastases that circulate in the peripheral blood. CTCs are potential seeds for metastases, and their detection may ...allow early uncovering of metastatic dissemination and disease prognostication. To fully ascertain the biomarker potential of melanoma CTCs, sensitive and reliable methods are required. Melanoma-specific transcript analysis has been widely utilized as a standard approach for measuring the presence of CTCs. Here we describe a method for the analysis of CTCs through the detection of specific transcripts in CTC-enriched fractions.
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