Diagnostic sensitivity of pleural fluid cytology in malignant pleural effusions: systematic review and meta-analysis.

BACKGROUND: Pleural fluid cytology is an important diagnostic test used for the investigation of pleural effusions. There is considerable variability in the reported sensitivity for the diagnosis of malignant pleural effusions (MPE) in the literature. OBJECTIVE: The purpose of this review is to determine the diagnostic sensitivity of pleural fluid cytology for MPE, both overall and by tumour type, to better inform the decision-making process when investigating pleural effusions. DATA SOURCES: A literature search of EMBASE and MEDLINE was performed by four reviewers. Articles satisfying inclusion criteria were evaluated for bias using the QUADAS-2 tool. DATA EXTRACTION: For quantitative analysis, we performed a metaanalysis using a binary random-effects model to determine pooled sensitivity. Subgroup analysis was performed based on primary cancer site and meta-regression by year of publication. SYNTHESIS: Thirty-six studies with 6057 patients with MPE were included in the meta-analysis. The overall diagnostic sensitivity of pleural fluid cytology for MPE was 58.2% (95% CI 52.5% to 63.9%; range 20.5%-86.0%). There was substantial heterogeneity present among studies (I2 95.5%). For primary thoracic malignancies, sensitivity was highest in lung adenocarcinoma (83.6%; 95% CI 77.7% to 89.6%) and lowest in lung squamous cell carcinoma (24.2%; 95% CI 17.0% to 31.5%) and mesothelioma (28.9%; 95% CI 16.2% to 41.5%). For malignancies with extrathoracic origin, sensitivity was high for ovarian cancer (85.2%; 95% CI 74.2% to 96.1%) and modest for breast cancer (65.3%; 95% CI 49.8% to 80.8%). CONCLUSIONS: Pleural fluid cytology has an overall sensitivity of 58.2% for the diagnosis of MPE. Clinicians should be aware of the high variability in diagnostic sensitivity by primary tumour type as well as the potential reasons for false-negative cytology results.PROSPERO registration numberCRD42021231473.

Two common variants of human papillomavirus type 16 E6 differentially deregulate sugar metabolism and hypoxia signalling in permissive human keratinocytes.

Human papillomavirus type 16 (HPV16) is responsible for most cancers attributable to HPV infection and naturally occurring variants of the HPV16 E6 oncoprotein predispose individuals to varying risk for developing cancer. Population studies by us and others have demonstrated that the common Asian-American E6 (AAE6) variant is a higher risk factor for cervical cancer than the E6 of another common variant, the European prototype (EPE6). However, a complete understanding of the molecular processes fundamental to these epidemiological findings is still lacking. Our previously published functional studies of these two E6 variants showed that AAE6 had a higher immortalization and transformation potential than EPE6. Proteomic analysis revealed markedly different protein patterns between these variants, especially with respect to key cellular metabolic enzymes. Here, we tested the Warburg effect and hypoxia signalling (hallmarks of cancer development) as plausible mechanisms underlying these observations. Lactate and glucose production were enhanced in AAE6-transduced keratinocytes, likely due to raised levels of metabolic enzymes, but independent of hypoxia-inducible factor 1 alpha (HIF-1α) activity. The HIF-1α protein level and activity were elevated by AAE6 in hypoxic conditions, leading to a hypoxia-tolerant phenotype with enhanced migratory potential. The deregulation of HIF-1α was caused by the AAE6 variant's ability to augment mitogen-activated protein kinase/extracellular related kinase signalling. The present study reveals prominent underlying mechanisms of the AAE6's enhanced oncogenic potential.

Functional variants of human papillomavirus type 16 demonstrate host genome integration and transcriptional alterations corresponding to their unique cancer epidemiology.

BACKGROUND: Human papillomaviruses (HPVs) are a worldwide burden as they are a widespread group of tumour viruses in humans. Having a tropism for mucosal tissues, high-risk HPVs are detected in nearly all cervical cancers. HPV16 is the most common high-risk type but not all women infected with high-risk HPV develop a malignant tumour. Likely relevant, HPV genomes are polymorphic and some HPV16 single nucleotide polymorphisms (SNPs) are under evolutionary constraint instigating variable oncogenicity and immunogenicity in the infected host. RESULTS: To investigate the tumourigenicity of two common HPV16 variants, we used our recently developed, three-dimensional organotypic model reminiscent of the natural HPV infectious cycle and conducted various "omics" and bioinformatics approaches. Based on epidemiological studies we chose to examine the HPV16 Asian-American (AA) and HPV16 European Prototype (EP) variants. They differ by three non-synonymous SNPs in the transforming and virus-encoded E6 oncogene where AAE6 is classified as a high- and EPE6 as a low-risk variant. Remarkably, the high-risk AAE6 variant genome integrated into the host DNA, while the low-risk EPE6 variant genome remained episomal as evidenced by highly sensitive Capt-HPV sequencing. RNA-seq experiments showed that the truncated form of AAE6, integrated in chromosome 5q32, produced a local gene over-expression and a large variety of viral-human fusion transcripts, including long distance spliced transcripts. In addition, differential enrichment of host cell pathways was observed between both HPV16 E6 variant-containing epithelia. Finally, in the high-risk variant, we detected a molecular signature of host chromosomal instability, a common property of cancer cells. CONCLUSIONS: We show how naturally occurring SNPs in the HPV16 E6 oncogene cause significant changes in the outcome of HPV infections and subsequent viral and host transcriptome alterations prone to drive carcinogenesis. Host genome instability is closely linked to viral integration into the host genome of HPV-infected cells, which is a key phenomenon for malignant cellular transformation and the reason for uncontrolled E6 oncogene expression. In particular, the finding of variant-specific integration potential represents a new paradigm in HPV variant biology.

Hypoxia-inducible factor 1 and its role in viral carcinogenesis.

The advent of modern molecular biology has allowed for the discovery of several mechanisms by which oncoviruses promote carcinogenesis. Remarkably, nearly all human oncogenic viruses increase levels of the transcription factor hypoxia-inducible factor 1 (HIF-1). In this review, we highlight HIF-1׳s significance in viral oncogenesis, while providing an in-depth analysis of its activation mechanisms by the following oncoviruses: human papillomaviruses (HPVs), hepatitis B/C viruses (HBV/HCVs), Epstein-Barr virus (EBV), Kaposi׳s sarcoma-associated herpes virus (KSHV), and human T-cell lymphotropic virus (HTLV-1). We discuss virus-induced HIF-1׳s role in transcriptional upregulation of metabolic, angiogenic, and microenvironmental factors that are integral for oncogenesis. Admittedly, conclusive evidence is lacking as to whether activation of HIF-1 target genes is necessary for malignant transformation or merely a result thereof. In addition, a complete understanding of host-virus interactions, the effect of viral genomic variation, and the clinical (and potential therapeutic) relevance of HIF-1 in viral oncogenesis warrant further investigation.