Identifying Thoracic Malignancies Through Pleural Fluid Biomarkers: A Predictive Multivariate Model

Liquid Biopsy in Lung Cancer: Biomarkers for the Management of Recurrence and Metastasis

Liquid biopsies have emerged as a promising tool for the detection of metastases as well as local and regional recurrence in lung cancer. Liquid biopsy tests involve analyzing a patient's blood, urine, or other body fluids for the detection of biomarkers, including circulating tumor cells or tumor-derived DNA/RNA that have been shed into the bloodstream. Studies have shown that liquid biopsies can detect lung cancer metastases with high accuracy and sensitivity, even before they are visible on imaging scans. Such tests are valuable for early intervention and personalized treatment, aiming to improve patient outcomes. Liquid biopsies are also minimally invasive compared to traditional tissue biopsies, which require the removal of a sample of the tumor for further analysis. This makes liquid biopsies a more convenient and less risky option for patients, particularly those who are not good candidates for invasive procedures due to other medical conditions. While liquid biopsies for lung cancer metastases and relapse are still being developed and validated, they hold great promise for improving the detection and treatment of this deadly disease. Herein, we summarize available and novel approaches to liquid biopsy tests for lung cancer metastases and recurrence detection and describe their applications in clinical practice.

Diagnosing pleural effusions using mass spectrometry-based multiplexed targeted proteomics quantitating mid- to high-abundance markers of cancer, infection/inflammation and tuberculosis

Pleural effusion (PE) is excess fluid in the pleural cavity that stems from lung cancer, other diseases like extra-pulmonary tuberculosis (TB) and pneumonia, or from a variety of benign conditions. Diagnosing its cause is often a clinical challenge and we have applied targeted proteomic methods with the aim of aiding the determination of PE etiology. We developed a mass spectrometry (MS)-based multiple reaction monitoring (MRM)-protein-panel assay to precisely quantitate 53 established cancer-markers, TB-markers, and infection/inflammation-markers currently assessed individually in the clinic, as well as potential biomarkers suggested in the literature for PE classification. Since MS-based proteomic assays are on the cusp of entering clinical use, we assessed the merits of such an approach and this marker panel based on a single-center 209 patient cohort with established etiology. We observed groups of infection/inflammation markers (ADA2, WARS, CXCL10, S100A9, VIM, APCS, LGALS1, CRP, MMP9, and LDHA) that specifically discriminate TB-PEs and other-infectious-PEs, and a number of cancer markers (CDH1, MUC1/CA-15-3, THBS4, MSLN, HPX, SVEP1, SPINT1, CK-18, and CK-8) that discriminate cancerous-PEs. Some previously suggested potential biomarkers did not show any significant difference. Using a Decision Tree/Multiclass classification method, we show a very good discrimination ability for classifying PEs into one of four types: cancerous-PEs (AUC: 0.863), tuberculous-PEs (AUC of 0.859), other-infectious-PEs (AUC of 0.863), and benign-PEs (AUC: 0.842). This type of approach and the indicated markers have the potential to assist in clinical diagnosis in the future, and help with the difficult decision on therapy guidance.

Development of risk prediction models for lung cancer based on tumor markers and radiological signs

Background

Accurate prediction of malignancy risk for pulmonary lesions with pleural effusion improves early diagnosis of lung cancer. This study aimed to develop and validate a model to predict lung cancer.

Methods

Clinical data of 536 patients with pulmonary diseases were collected. The risk factors were identified by regression analysis. Three prediction models were developed. The predictive performances of the models were measured by the area under the curves (AUCs) and calibrated with 1000 bootstrap samples to minimize the over‐fitting bias. The net benefits of the models were evaluated by decision curve analysis. Finally, a separate cohort of 134 patients was used to validate the models externally.

Results

Seven independent risk factors were identified from 18 clinical variables, which included the pleural fluid carcinoembryonic antigen (CEA), serum cytokeratin‐19 fragment (CYFRA 21‐1), the ratio of CEA in the pleural fluid to serum, extrathoracic cancer history (>5 years), tumor size, vessel convergence, and lobulation. The AUCs of the three models were 0.976, 0.927, and 0.944 in the training set and 0.930, 0.845, and 0.944 in the external set, respectively. The accuracies of the three models were 89.6%, 81.4%, and 88.8%. Model 1 showed the best iteration fit (R² = 0.84, 0.68, and 0.73) and a higher net benefit on decision curve analysis when compared to the other two models.

Conclusion

The advantageous model could assess the risk of lung cancer in patients with pleural effusion and act as a useful tool for early identification of lung cancer.

Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment

BACKGROUND

Pleural effusion is common in routine medical practice and can be due to many different underlying diseases. Precise differential diagnostic categorization is essential, as the treatment and prognosis of pleural effusion largely depend on its cause.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and on the authors' personal experience.

RESULTS

The most common causes of pleural effusion are congestive heart failure, cancer, pneumonia, and pulmonary embolism. Pleural fluid puncture (pleural tap) enables the differentiation of a transudate from an exudate, which remains, at present, the foundation of the further diagnostic work-up. When a pleural effusion arises in the setting of pneumonia, the potential devel- opment of an empyema must not be overlooked. Lung cancer is the most common cause of malignant pleural effusion, followed by breast cancer. Alongside the treatment of the underlying disease, the specific treatment of pleural effusion ranges from pleurodesis, to thoracoscopy and video-assisted thoracoscopy (with early consultation of a thoracic surgeon), to the placement of a permanently indwelling pleural catheter.

CONCLUSION

The proper treatment of pleural effusion can be determined only after meticulous differential diagnosis. The range of therapeutic options has recently become much wider. More data can be expected in the near future concerning diagnostic test- ing for the etiology of the effusion, better pleurodetic agents, the development of interventional techniques, and the genetic background of the affected patients.

The clinical utility of joined detection of cancer ratio, cancer ratio plus, Interferon gamma (IFN-ϒ) & Carcinoembryonic antigen (CEA) in differentiating lymphocytic pleural effusions

Background

The differentiation between malignant (MPE) and tuberculous (TPE) pleural effusions should be considered in any patient with an exudative lymphocytic pleural effusion. A rapid precise diagnosis is valuable as the treatment and prognosis are totally different. The histopathological proof may shorten the time to differential diagnosis. But it may be invasive and costly. The aim of this study is to validate the clinical reliability of joined detection of cancer ratio (serum LDH to pleural ADA), cancer ratio plus (cancer ratio to percentage of pleural fluid lymphocytic count), pleural interferon gamma (pIFN-ϒ), and pleural carcinoembryonic antigen (pCEA) values to differentiate between lymphocytic pleural effusions.

Results

Seventy-eight patients were included with mean age ± SD 53.09 ± 9.56 years old, 49 males and 29 females, diagnosed as 47 MPE, 24 TPE, and 7 others. Cancer ratio at cutoff value of ≥ 22 and cancer ration plus at cutoff value of ≥ 41 can discriminate MPE from any other cause with sensitivity (91.5%, 93.6%), specificity (87.5%, 91.7%), and diagnostic accuracy (90.1%, 92.9%) respectively. When the levels of pCEA and pIFN-ϒ were combined with cutoff value of cancer ratio, there were powerful diagnostic differentiating results.

Conclusions

Cancer ratio and cancer ratio plus offered valid, efficient, non-invasive, and easy measuring diagnostic tools. On diagnostic uncertainty, the add-on of pCEA in cases of suspected MPE, and pIFN-ϒ in cases of suspected TPE has a trustable diagnostic efficacy with no need for further investigations.

The value of apolipoprotein E in distinguishing benign and malignant unilateral pleural effusions

Pleural effusion (PE) remains insurmountable challenge and public health problem, requiring novel noninvasive biomarkers for accurate diagnosis. The aim of this study was to assess the clinical significance of apolipoprotein E (Apo-E) in PE, in order to determine its potential use as a diagnostic biomarker for malignant PE (MPE).PE samples were obtained from 127 patients and the etiology of PE was determined by multiple diagnostic techniques. Apo-E levels were then measured in the pleural fluid samples.58 PE patients were diagnosed with tumors, while 69 were tumor-free. Apo-E levels in MPE patients were significantly higher than those with benign PE (BPE) (P < .05). An Apo-E cut-off of 69.96 ng/mL yielded sensitivity and specificity of 79.31% and 73.91% respectively for MPE detection. The area under the curve for Apo-E was 0.793 (95% confidence interval: 0.712 to 0.860), which was smaller than that of carcinoembryonic antigen (CEA) (Z = 2.081, P<.05). In addition, the combination of Apo-E and CEA detection yielded a higher sensitivity of 87.90% and specificity of 95.65% in diagnosing MPE.In conclusion, Apo-E levels in PE may be a potential biomarker for the detection of MPE. The combined detection of Apo-E and CEA could improve the diagnostic sensitivity and specificity for MPE. These findings provide a simple and convenient method for clinical screening and detection of PE.

Biomarkers in the diagnosis of pleural diseases: a 2018 update

The use of biomarkers on pleural fluid (PF) specimens may assist the decision-making process and enhance clinical diagnostic pathways. Three paradigmatic examples are heart failure, tuberculosis and, particularly, malignancy. An elevated PF concentration of the amino-terminal fragment of probrain natriuretic peptide (>1500 pg/ml) is a hallmark of acute decompensated heart failure. Adenosine deaminase, interferon-γ and interleukin-27 are three valuable biomarkers for diagnosing tuberculous pleurisy, yet only the first has been firmly established in clinical practice. Diagnostic PF biomarkers for malignancy can be classified as soluble-protein based, immunocytochemical and nucleic-acid based. Soluble markers (e.g. carcinoembryonic antigen (CEA), carbohydrate antigen 15-3, mesothelin) are only indicative of cancer, but not confirmatory. Immunocytochemical studies on PF cell blocks allow: (a) to distinguish mesothelioma from reactive mesothelial proliferations (e.g. loss of BAP1 nuclear expression, complemented by the demonstration of p16 deletion using fluorescence in situ hybridization, indicate mesothelioma); (b) to separate mesothelioma from adenocarcinoma (e.g. calretinin, CK 5/6, WT-1 and D2-40 are markers of mesothelioma, whereas CEA, EPCAM, TTF-1, napsin A, and claudin 4 are markers of carcinoma); and (c) to reveal tumor origin in pleural metastases of an unknown primary site (e.g. TTF-1 and napsin A for lung adenocarcinoma, p40 for squamous lung cancer, GATA3 and mammaglobin for breast cancer, or synaptophysin and chromogranin A for neuroendocrine tumors). Finally, PF may provide an adequate sample for analysis of molecular markers to guide patients with non-small cell lung cancer to appropriate targeted therapies. Molecular testing must include, at least, mutations of epidermal growth-factor receptor and BRAF V600E, translocations of rat osteosarcoma and anaplastic lymphoma kinase, and expression of programmed death ligand 1.

Malignant Pleural Effusion: From Diagnostics to Therapeutics

Malignant pleural effusion is a common complication of cancer and denotes a poor prognosis. It usually presents with dyspnea and a unilateral large pleural effusion. Thoracic computed tomography scans and ultrasound are helpful in distinguishing malignant from benign effusions. Pleural fluid cytology is diagnostic in about 60% of cases. In cytology-negative disease, pleural biopsies are helpful. Current management is palliative. Previously, first-line treatment for recurrent symptomatic malignant pleural effusion was chest drain insertion and talc pleurodesis, with indwelling pleural catheter insertion reserved for patients with trapped lung or failed talc pleurodesis. However, catheter insertion is an increasingly acceptable first-line treatment.

Diagnostic value of soluble B7-H4 and carcinoembryonic antigen in distinguishing malignant from benign pleural effusion

OBJECTIVE

To explore the diagnostic value of joint detection of soluble B7-H4 (sB7-H4) and carcinoembryonic antigen (CEA) in identifying malignant pleural effusion (MPE) from benign pleural effusion (BPE).

METHODS

A total of 97 patients with pleural effusion specimens were enrolled from The First Affiliated Hospital of Zhengzhou University between June 2014 and December 2015. All cases were categorized into malignant pleural effusion group (n = 55) and benign pleural effusion group (n = 42) according to etiologies. Enzyme-linked immunosorbent assay was applied to examine the levels of sB7-H4 in pleural effusion and meanwhile CEA concentrations were detected by electro-chemiluminescence immunoassays. Receiver operating characteristic (ROC) curve was established to assess the diagnostic value of sB7-H4 and CEA in pleural effusion. The correlation between sB7-H4 and CEA levels was analyzed by Pearson's product-moment.

RESULTS

The concentrations of sB7-H4 and CEA in MPE exhibited obviously higher than those of BPE ([60.08 ± 35.04] vs. [27.26 ± 9.55] ng/ml, P = .000; [41.49 ± 37.16] vs. [2.41 ± 0.94] ng/ml, P = .000). The AUC area under ROC curve of sB7-H4 and CEA was 0.884 and 0.954, respectively. Two cutoff values by ROC curve analysis of sB7-H4 36.5 ng/ml and CEA 4.18 ng/ml were obtained, with a corresponding sensitivity (81.82%, 87.28%), specificity (90.48%, 95.24%), accuracy (85.57%, 90.72%), positive predictive value (PPV) (91.84%, 96.0%), negative predictive value (NPV) (79.17%, 85.11%), positive likelihood ratio (PLR) (8.614, 18.327), and negative likelihood ratio (NLR) (0.201, 0.134). When sB7-H4 and CEA were combined to detect pleural effusion, it obtained a higher sensitivity 90.91% and specificity 97.62%. Furthermore, correlation analysis result showed that the level of sB7-H4 was correlated with CEA level (r = .770, P = .000).

CONCLUSIONS

sB7-H4 was a potentially valuable tumor marker in the differentiation between BPE and MPE. The combined detection of sB7-H4 and CEA could improve the diagnostic sensitivity and specificity for MPE.

Differentiating Malignant from Tubercular Pleural Effusion by Cancer Ratio Plus (Cancer Ratio: Pleural Lymphocyte Count)

Background. We performed prospective validation of the cancer ratio (serum LDH : pleural ADA ratio), previously reported as predictive of malignant effusion retrospectively, and assessed the effect of combining it with “pleural lymphocyte count” in diagnosing malignant pleural effusion (MPE). Methods. Prospective cohort study of patients hospitalized with lymphocyte predominant exudative pleural effusion in 2015. Results. 118 patients, 84 (71.2%) having MPE and 34 (28.8%) having tuberculous pleural effusion (TPE), were analysed. In multivariate logistic regression analysis, cancer ratio, serum LDH : pleural fluid lymphocyte count ratio, and “cancer ratio plus” (ratio of cancer ratio and pleural fluid lymphocyte count) correlated positively with MPE. The sensitivity and specificity of cancer ratio, ratio of serum LDH : pleural fluid lymphocyte count, and “cancer ratio plus” were 0.95 (95% CI 0.87–0.98) and 0.85 (95% CI 0.68–0.94), 0.63 (95% CI 0.51–0.73) and 0.85 (95% CI 0.68–0.94), and 97.6 (95% CI 0.90–0.99) and 94.1 (95% CI 0.78–0.98) at the cut-off level of >20, >800, and >30, respectively. Conclusion. Without incurring any additional cost, or requiring additional test, effort, or time, cancer ratio maintained and “cancer ratio plus” improved the specificity of cancer ratio in identifying MPE in the prospective cohort.