Multicenter evaluation of a new progastrin-releasing peptide (ProGRP) immunoassay across Europe and China

Assessing the diagnostic utility of serum tumor markers for lung cancer detection in patients with interstitial pneumonia

BACKGROUND

The prevalence of lung cancer among individuals afflicted with interstitial pneumonia (IP) stands at approximately 20%. The early detection of lung cancer via chest computed tomography (CT) surveillance proves challenging in IP patients. Our investigation sought to identify a potential biomarker capable of providing early indications of the presence of lung tumors in such patients.

MATERIALS AND METHODS

We examined the attributes of serum tumor markers, imaging characteristics, and histological findings in individuals diagnosed with IP, both with and without concurrent lung cancer.

RESULTS

106 patients diagnosed with IP were included in the study, comprising 36 individuals with concurrent lung cancer and 70 patients solely diagnosed with IP. Serum concentrations of CEA and CA12-5 were notably elevated in IP patients with lung cancer, compared to those with IP alone. Logistic regression analyses revealed that, in comparison to IP patients within the first quartile of CEA levels, the relative risk of developing lung cancer associated with IP escalated by 4.0-fold, 3.1-fold, 11.0-fold, and 13.3-fold in the second, third, fourth, and fifth quartiles, respectively. Upon controlling for gender and age, statistical significance in risk was observed solely for the fourth and fifth quartiles. Receiver operating characteristic (ROC) curve analysis conducted in patients diagnosed with ILD-CA identified a CEA cutoff point of 6.9 ng/mL, demonstrating sensitivities of 61.1% and specificities of 78.5%. The area under the curve was calculated as 0.7(95% CI: 0.63-0.81).

CONCLUSION

The serum levels of CEA were notably elevated in IP patients with concurrent lung cancer in contrast to those who were just suffering from IP. The heightened serum CEA levels correlate with an escalated risk of cancer occurrence among IP patients, suggesting that serum CEA levels could potentially serve as an indicative marker for the presence of cancer in IP patients.

Clinical practice guidelines for molecular tumor marker, 2nd edition review part 2

In recent years, rapid advancement in gene/protein analysis technology has resulted in target molecule identification that may be useful in cancer treatment. Therefore, "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" was published in Japan in September 2021. These guidelines were established to align the clinical usefulness of external diagnostic products with the evaluation criteria of the Pharmaceuticals and Medical Devices Agency. The guidelines were scoped for each tumor, and a clinical questionnaire was developed based on a serious clinical problem. This guideline was based on a careful review of the evidence obtained through a literature search, and recommendations were identified following the recommended grades of the Medical Information Network Distribution Services (Minds). Therefore, this guideline can be a tool for cancer treatment in clinical practice. We have already reported the review portion of "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" as Part 1. Here, we present the English version of each part of the Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition.

Novel Tools for Single Comparative and Unified Evaluation of Qualitative and Quantitative Bioassays: SS/PV-ROC and SS-J/PV-PSI Index-ROC Curves with Integrated Concentration Distributions, and SS-J/PV-PSI Index Cut-Off Diagrams

Background: This investigation is both a study of potential non-invasive diagnostic approaches for the bladder cancer biomarker UBC® Rapid test and a study including novel comparative methods for bioassay evaluation and comparison that uses bladder cancer as a useful example. The objective of the paper is not to investigate specific data. It is used only for demonstration, partially to compare ROC methodologies and also to show how both sensitivity/specificity and predictive values can be used in clinical diagnostics and decision making. This study includes ROC curves with integrated cut-off distribution curves for a comparison of sensitivity/specificity (SS) and positive/negative predictive values (PPV/NPV or PV), as well as SS-J index/PV-PSI index-ROC curves and SS-J/PV-PSI index cut-off diagrams (J = Youden, PSI = Predictive Summary Index) for the unified direct comparison of SS-J/PV results achieved via quantitative and/or qualitative bioassays and an identification of optimal separate or unified index cut-off points. Patients and Methods: According to the routine diagnostics, there were 91 patients with confirmed bladder cancer and 1152 patients with no evidence of bladder cancer, leading to a prevalence value of 0.073. This study performed a quantitative investigation of used-up test cassettes from the visual UBC® Rapid qualitative point-of-care assay, which had already been applied in routine diagnostics. Using a photometric reader, quantitative data could also be obtained from the test line of the used cassettes. Interrelations between SS and PV values were evaluated using cumulative distribution analysis (CAD), SS/PV-ROC curves, SS-J/PV-PSI index-ROC curves, and the SS-J/PV-PSI index cut-off diagram. The maximum unified SS-J/PV-PSI index value and its corresponding cut-off value were determined and calculated with the SS-J/PV-PSI index cut-off diagram. Results: The use of SS/PV-ROC curves with integrated cut-off concentration distribution curves provides improved diagnostic information compared to "traditional" ROC curves. The threshold distributions integrated as curves into SS/PV-ROC curves and SS-J/PV-PSI index-ROC curves run in opposite directions. In contrast to the SS-ROC curves, the PV-ROC and the novel PV-PSI index-ROC curves had neither an area under the curve (AUC) nor a range from 0% to 100%. The cut-off level of the qualitative assay was 7.5 µg/L, with a sensitivity of 65.9% and a specificity of 63.3%, and the PPV was 12.4% and the NPV was 95.9%, at a threshold value of 12.5 µg/L. Based on these set concentrations, the reader-based evaluation revealed a graphically estimated 5% increase in sensitivity and a 13% increase in specificity, as compared to the visual qualitative POC test. In the case of predictive values, there was a gain of 8% for PPV and 10% for NPV. The index values and cut-offs were as follows: visual SS-J index, 0.328 and 35 µg/L; visual PV-PSI index, 0.083 and 5.4 µg/L; maximal reader Youden index, 0.0558 and 250 µg/L; and maximal PV-PSI index, 0.459 and 250 µg/L, respectively. The maximum unified SS-J/PV-PSI index value was 0.32, and the cut-off was 43 µg/L. The reciprocal SS-J index correctly detected one out of three patients, while the reciprocal PV-PSI index gave one out of twelve patients a correct diagnosis. Conclusions: ROC curves including cut-off distribution curves supplement the information lost in "traditionally plotted" ROC curves. The novel sets of ROC and index-ROC curves and the new SS/PV index cut-off diagrams enable the simultaneous comparison of sensitivity/specificity and predictive value profiles of diagnostic tools and the identification of optimal cut-off values at maximal index values, even in a unifying SS/PV approach. Because the curves within an SS-J/PV-PSI index cut-off diagram are distributed over the complete cut-off range of a quantitative assay, this field is open for special clinical considerations, with the need to vary the mentioned clinical diagnostic parameters. Complete or partial areas over the x-axis (AOX) can be calculated for summarized quantitative or qualitative effectivity evaluations with respect to single and/or unified SS-J and PV-PSI indices and with respect to single, several, or several unified assays. The SS-J/PV-PSI index-AOX approach is a new tool providing additional joint clinical information, and the reciprocal SS-J indices can predict the number of patients with a correct diagnosis and the number of persons who need to be examined in order to correctly predict a diagnosis of the disease. These methods could be used in applications like medical or plant epidemiology, machine learning algorithms, and neural networks.

Relevance of tumor markers for prognosis and predicting therapy response in non-small cell lung cancer patients: A CEPAC-TDM biomarker substudy

BACKGROUND

Protein tumor markers are released in high amounts into the blood in advanced non-small cell lung cancer (NSCLC).

OBJECTIVE

To investigate the relevance of serum tumor markers (STM) for prognosis, prediction and monitoring of therapy response in NSCLC patients receiving chemotherapy.

METHODS

In a biomarker substudy of a prospective, multicentric clinical trial (CEPAC-TDM) on 261 advanced NSCLC patients, CYFRA 21-1, CEA, SCC, NSE, ProGRP, CA125, CA15-3 and HE4 were assessed in serial serum samples and correlated with radiological response after two cycles of chemotherapy and overall (OS) and progression-free survival (PFS).

RESULTS

While pretherapeutic STM levels at staging did not discriminate between progressive and non-progressive patients, CYFRA 21-1, CA125, NSE and SCC at time of staging did, and yielded AUCs of 0.75, 0.70, 0.69 and 0.67 in ROC curves, respectively. High pretherapeutic CA15-3 and CA125 as well as high CYFRA 21-1, SCC, CA125 and CA15-3 levels at staging were prognostic for shorter PFS and OS -also when clinical variables were added to the models.

CONCLUSIONS

STM at the time of first radiological staging and pretherapeutic CA15-3, CA125 are predictive for first-line treatment response and highly prognostic in patients with advanced NSCLC.

Circulating lung cancer biomarkers: From translational research to clinical practice

Fundamental studies on biomarkers as well as developed assays for their detection can provide valuable information facilitating clinical decisions. For patients with lung cancer, there are established circulating biomarkers such as serum progastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCC-Ag), carcinoembryonic antigen (CEA), and cytokeratin-19 fragment (CYFRA21-1). There are also molecular biomarkers for targeted therapy such as epidermal growth factor receptor (EGFR) gene, anaplastic lymphoma kinase (ALK) gene, KRAS gene, and BRAF gene. However, there is still an unmet need for biomarkers that can be used for early detection and predict treatment response and survival. In this review, we describe the lung cancer biomarkers that are currently being used in clinical practice. We also discuss emerging preclinical and clinical studies on new biomarkers such as omics-based biomarkers for their potential clinical use to detect, predict, or monitor subtypes of lung cancer. Additionally, between-method differences in tumor markers warrant further development and improvement of the standardization and harmonization for each assay.

Blood protein biomarkers in lung cancer

Lung cancer has consistently ranked first as the cause of cancer-associated mortality. The 5-year survival rate has risen slowly, and the main obstacle to improving the prognosis of patients has been that lung cancer is usually diagnosed at an advanced or incurable stage. Thus, early detection and timely intervention are the most effective ways to reduce lung cancer mortality. Tumor-specific molecules and cellular elements are abundant in circulation, providing real-time information in a noninvasive and cost-effective manner during lung cancer development. These circulating biomarkers are emerging as promising tools for early detection of lung cancer and can be used to supplement computed tomography screening, as well as for prognosis prediction and treatment response monitoring. Serum and plasma are the main sources of circulating biomarkers, and protein biomarkers have been most extensively studied. In this review, we summarize the research progress on three most common types of blood protein biomarkers (tumor-associated antigens, autoantibodies, and exosomal proteins) in lung cancer. This review will potentially guide researchers toward a more comprehensive understanding of candidate lung cancer protein biomarkers in the blood to facilitate their translation to the clinic.

A continuous responder algorithm to optimize clinical management of small-cell lung cancer with progastrin-releasing peptide as a simple blood test

This study aimed to investigate whether changes in progastrin-releasing peptide (ProGRP) levels correlate with treatment response and can be used to optimize clinical management of patients with small-cell lung cancer. Patients with small-cell lung cancer (any stage) receiving chemotherapy were eligible. ProGRP was measured in serum/plasma at baseline and after each chemotherapy cycle using the Elecsys^® ProGRP assay (Roche Diagnostics). Treatment response was assessed by computed tomography scan. The primary objective was to examine whether changes in ProGRP levels correlated with computed tomography scan results after two cycles of chemotherapy. The prognostic value of ProGRP among patients receiving first-line chemotherapy was also assessed. Overall, 261 patients from six centers were eligible. Among patients with elevated baseline ProGRP (>100 pg/mL), a ProGRP decline after Cycle 2 was associated with nonprogression (area under the curve: 84%; 95% confidence interval: 72.8-95.1; n = 141). ProGRP changes from baseline to end of Cycle 1 were predictive of response, as determined by computed tomography scan 3 weeks later (area under the curve: 87%; 95% confidence interval: 74.1-99.2; n = 137). This was enhanced by repeat measurements, with a 92% area under the curve (95% confidence interval: 85.3-97.8) among patients with ProGRP data after both Cycles 1 and 2 (n = 123); if a patient experienced a ≥25% decline in ProGRP after Cycle 1, and ProGRP remained stable or decreased after Cycle 2, the probability of finding progression on the interim computed tomography scan at the end of Cycle 2 was almost zero (sensitivity: 100%, specificity: 71%). Both ProGRP levels at baseline and at the end of first-line chemotherapy were prognostic; the latter provided a moderately improved hazard ratio of 2.43 (95% confidence interval: 1.33-4.46; n = 110) versus 1.87 (95% confidence interval: 1.04-3.37; n = 216). In summary, for patients with small-cell lung cancer and elevated baseline ProGRP levels, ProGRP may be a simple, reliable, and repeatable tool for monitoring response to chemotherapy and provide valuable prognostic information.

Selective application of neuroendocrine markers in the diagnosis and treatment of small cell lung cancer

AIMS

Here, we explored the potential application and selection of neuroendocrine biomarkers in the diagnosis and treatment of small cell lung cancer.

METHODS

We retrospectively analyzed 118 patients with small cell lung cancer (SCLC), 166 patients with non-small cell lung cancer (NSCLC), 33 patients with benign lung disease (BLD), and 200 healthy individuals admitted to Zhejiang Provincial People's Hospital between January 1, 2015 and May 31, 2019. All the patients were newly diagnosed with either SCLC, NSCLC, or BLD and previously untreated. Peripheral blood levels of ProGRP, NSE, CEA, and CYFRA21-1 were analyzed during the follow-up treatment, and 2-fold upper limit of reference intervals were defined as effective elevation. We used paired results to analyze the diagnostic efficiency of proGRP and NSE on SCLC.

RESULTS

In the 118 SCLC patients, proGRP levels were significantly higher compared with NSE levels. The diagnostic efficiencies of NSE and ProGRP for SCLC were 0.8554 and 0.9053, respectively. The combined diagnostic efficiency (0.9426) was higher relative to NSE, but there was no significant difference compared with proGRP. The effective elevation rate of proGRP was 45.3% higher than that of NSE in the limited stage of SCLC. In the extensive disease of SCLC patients, 70.7% cases had more than 10-fold increase in proGRP value, whereas 56.9% cases had less than 5-fold increase in NSE value. Compared with pre-treatment, the median concentrations of proGRP increased by 204.0% higher than that of NSE (71.3%) in the progressive group. Besides, the dynamic change in imaging characteristics and tumor size had a strong correlation with the levels of proGRP.

SIGNIFICANCE

ProGRP is a reliable neuroendocrine biomarker in SCLC. The effective elevation of proGRP has a potential diagnostic and efficacy value in the evaluation of SCLC. However, the combined detection of proGRP and NSE does not significantly improve the diagnosis of lung cancer.

Metabolomic profiling of dried blood spots reveals gender-specific discriminant models for the diagnosis of small cell lung cancer

The accurate diagnosis of small cell lung cancer (SCLC) at initial presentation is essential to ensure appropriate treatment. No validated blood biomarkers that could distinguish SCLC from non-small cell lung cancer (NSCLC) has yet been developed. Dried blood spot (DBS) microsampling has gained increasing interest in biomarkers discovery. In this study, we first performed metabolomic profiling of DBS samples from 37 SCLC, 40 NSCLC, and 37 controls. Two gender-specific multianalyte discriminant models were established for males and females, respectively to distinguish SCLC from NSCLC and controls. The receiver operator characteristic (ROC) curve analysis showed the diagnostic accuracy of 95% (95% CI: 83%-100%) in males SCLC using five metabolites in DBS and 94% (95% CI: 74%-100%) for females using another set of five metabolites. The robustness of the models was confirmed by the random permutation tests (P < 0.01 for both). The performance of the discriminant models was further evaluated using a validation cohort with 78 subjects. The developed discriminant models yielded an accuracy of 91% and 81% for males and females, respectively, in the validation cohort. Our results highlighted the potential clinical utility of the metabolomic profiling of DBS as a convenient and effective approach for the diagnosis of SCLC.

Increased Progastrin-Releasing Peptide Expression is Associated with Progression in Gastric Cancer Patients

PURPOSE

The purpose of this study was to assess the diagnostic and prognostic value of serum progastrin-releasing peptide (ProGRP) in patients with gastric cancer (GC).

MATERIALS AND METHODS

A total of 150 patients with GC (89 males and 61 females) were recruited, including those with stage I (n=28), stage II (n=33), stage III (n=50), and stage IV (n=39) disease; 50 healthy controls and 66 patients with benign gastric diseases were also enrolled. Levels of serum ProGRP, carcinoembryonic antigen (CEA), and carbohydrate antigen 72-4 (CA72-4) were measured in all subjects.

RESULTS

Serum ProGRP levels were significantly higher in GC patients than in controls (p<0.001), and ProGRP was significantly correlated with tumor size, tumor node metastasis stage, differentiation, invasion depth, and lymph node metastasis (p< 0.005). ProGRP levels were significantly decreased after chemotherapy (p<0.001). Receiver operating characteristic curves revealed a sensitivity and specificity for serum ProGRP in GC of 85.9% and 81.2%, respectively. ProGRP levels were positively correlated with CA72-4 and CEA (r=0.792 and 0.688, p<0.05, respectively). Combined detection of ProGRP, CEA, and CA72-4 showed the best diagnostic power for GC.

CONCLUSION

ProGRP may be useful as a potential biomarker for GC diagnosis and therapy.

Evaluation of chemiluminescent immunoassay quantitative detection for pro-gastrin-releasing peptide (ProGRP) in serum and plasma

OBJECTIVE

To evaluate a newly developed Hybiome ProGRP chemiluminescent assay.

METHODS

Analytical sensitivity, precision, recovery, and equivalency of serum and plasma, serum stability, and complement interference of the Hybiome ProGRP assay were evaluated. Serum specimens from 318 individuals including 38 small cell lung cancer (SCLC), 65 non-small cell lung cancer (NSCLC), 53 benign lung diseases, and 162 healthy controls were assessed using the Hybiome ProGRP assay and Roche Elecsys ProGRP assay, and the results were compared.

RESULTS

The Hybiome ProGRP assay showed good analytical sensitivity, precision, and accuracy, and it showed equivalence between serum and plasma and serum stability. The methodological comparison results showed good correlation between the Hybiome and Roche assays (slope, 0.9889; intercept, 1.28). Both the Hybiome and Roche assays showed good ability to distinguish between SCLC and NSCLC. Based on 95% specificity in the NSCLC cohort, a clinical differentiation cut-off for separating SCLC from NSCLC patients was 114 pg/mL for the Hybiome assay and 117 pg/mL for the Roche assay; the AUC was 0.9166 and the sensitivity was 71.05% for Hybiome and 0.9045 and 76.32% for Roche, respectively.

CONCLUSION

The Hybiome ProGRP chemiluminescent assay shows good analytical performance and good correlation with the Roche Elecsys ProGRP assay.

Diagnostic value of ProGRP for small cell lung cancer in different stages

Background

To investigate the roles of gastrin-releasing peptide (ProGRP) in the diagnosis of small cell lung cancer (SCLC).

Methods

We retrospectively analyzed data from 11,206 patients with clinical suspicion of lung cancer from January 1, 2015 to May 31, 2018. ProGRP and neuron-specific enolase (NSE) were detected in peripheral blood, and receiver operating characteristic curve (ROC) was used for analysis.

Results

ROC indicated that the cutoff values of ProGRP and NSE were 66 ng/L and 18 µg/L respectively, and the diagnosis efficacy of ProGRP was greater than that of NSE (sensitivity: 86.5% vs. 78.8%; specificity: 96.5% vs. 86.3%, respectively) in the diagnosis of SCLC. Moreover, the median level of ProGRP in SCLC increased with the accompanying stages (P<0.001). Further analysis showed that diagnostic efficacy can be improved by using different cutoff values in different stages, but not stage I and II. The cut-off values of ProGRP in the diagnosis of SCLC in stage I-II, III and IV were 56, 71 and 99 ng/L respectively. In addition, the sensitivity (96.6% vs. 95.8% and 98.3% vs. 94.8%) and concordance rate (χ² =1,526.9 and 988.7, both P<0.001) of detecting SCLC was improved by using different cutoff values compared with the only criteria of ProGRP being ≥66 ng/L in stage III and IV, but not stage I-II. Additionally in stage III and IV, the concordance rates of ProGRP ≥71 ng/L and ProGRP ≥99 ng/L were also higher than ProGRP ≥300 ng/L (both P<0.001), which was conventionally indicated for SCLC.

Conclusions

ProGRP has significantly higher sensitivity and specificity than NSE in the diagnosis of SCLC. Furthermore, special thresholds for every stage may be more reasonable for the diagnosis of SCLC.

Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers

Some biomarkers for functioning and non-functioning neuroendocrine neoplasms (NENs) are currently available. Despite their application in clinical practice, results should be interpreted cautiously. Considering the variable sensitivity and specificity of these parameters, there is an unmet need for novel biomarkers to improve diagnosis and predict patient outcome. Nowadays, several new biomarkers are being evaluated and may become future tools for the management of NENs. These biomarkers include (1) peptides and growth factors; (2) DNA and RNA markers based on genomics analysis, for example, the so-called NET test, which has been developed for analyzing gene transcripts in circulating blood; (3) circulating tumor/endothelial/progenitor cells or cell-free tumor DNA, which represent minimally invasive methods that would provide additional information for monitoring treatment response and (4) improved imaging techniques with novel radiolabeled somatostatin analogs or peptides. Below we summarize some future directions in the development of novel diagnostic and predictive/prognostic biomarkers in NENs. This review is focused on circulating and selected tissue markers.

Tissue and Blood Biomarkers in Lung Cancer: A Review

Lung cancer is the most common cause of cancer-related death, worldwide. Historically, lung cancer has been divided into two main histological types: small cell and nonsmall cell (NSC) type with the latter being subdivided into adenocarcinoma, squamous cell type, and large cell type. The treatment of the NSC lung cancer (NSCLC), especially the adenocarcinoma subtype, has been transformed in the last decade by the availability of predictive biomarkers for molecularly targeted therapies. Currently, for patients with advanced adenocarcinomas, testing for sensitizing mutations in epidermal growth factor receptor (EGFR) is mandatory prior to the administration of anti-EGFR inhibitors such as erlotinib, gefitinib, afatinib, or osimertinib. For patients unable to provide tumor tissue, EGFR mutational analysis may be performed on plasma. For predicting response to crizotinib, testing for ALK and ROS1 gene rearrangement is necessary. The presence of ALK rearrangements is also a prerequisite for treatment with ceritinib, alectinib, or brigatinib. For predicting response to single agent pembrolizumab in the first-line treatment of patients with advanced adenocarcinoma or squamous cell NSCLCs, PD-L1 should be measured by an approved assay (e.g., PD-L1 IHC 22C3 pharmDx method). Although not widely used, serum biomarkers such as neuron-specific enolase, progastrin-releasing peptide, carcinoembryonic antigen, CYFRA 21-1, and squamous cell carcinoma antigen may help in the differential diagnosis of lung cancer when a tissue diagnosis is not possible. Serum biomarkers may also be of use in determining prognosis and monitoring response to systemic therapies. With the increasing use of biomarkers, personalized treatment especially for patients with adenocarcinoma-type NSCLC is finally on the horizon.

Reference intervals for serum progastrin-releasing peptide in healthy Chinese adults with electrochemiluminescence immunoassay

BACKGROUND

Reliable reference intervals for serum progastrin-releasing peptide (ProGRP) in healthy Chinese adults with electrochemiluminescence immunoassay (ECLIA) are still lacking in the Chinese population.

OBJECTIVES

The study aims to establish reference intervals for ProGRP with ECLIA in apparently healthy Chinese adults.

METHODS

A total of 384 apparently healthy individuals from six representative geographical regions in China were enrolled: 200 males and 184 females with a mean age of 43.4±12.2 years, and an age range from 21 to 85 years. Serum ProGRP levels were analyzed on Cobas e601 automatic immunoassay analyzer with ECLIA. Reference intervals for serum ProGRP with ECLIA were determined following CLSI C28-A3 guidelines using a nonparametric method.

RESULTS

In an apparently healthy Chinese population, the reference intervals for serum ProGRP with ECLIA were ⩽53.92 ng/L for adults aged 21-70 years and ⩽75.69 ng/L for adults aged >70 years, respectively.

CONCLUSIONS

The reference values for serum ProGRP with ECLIA in an apparently healthy Chinese population were established according to the CLSI C28-A3 document, providing a reference for the clinical work.

Pro-gastrin-releasing peptide (ProGRP) as a biomarker in small-cell lung cancer diagnosis, monitoring and evaluation of treatment response

Lung cancer belongs to malignant tumors that possess the highest rates of morbidity and mortality in the world. A number of morphological, biological and clinical features justify the distinction of small-cell carcinoma with respect to the other histological types of lung cancer. The predominant neuroendocrine phenotype is critical for the selection of biomarkers used in diagnostics, monitoring and evaluation of treatment response; early onset relapses in patients with small-cell lung cancer (SCLC) and the evaluation of their prognosis. Although for a long time the neuron-specific enolase (NSE) was considered to be the marker of choice for this tumor, it is now increasingly important to pay attention to concentrations of pro-gastrin-releasing peptide (ProGRP). The results of this marker have been implicated in the differential diagnosis of non-small lung cancer and SCLC, chemotherapy and radiotherapy monitoring as well as evaluation of treatment response. The subject of this series of studies is to determine the usefulness of ProGRP in the evaluation of patients’ prognosis and its predictive value. The current aim for the optimization of the effectiveness of biochemical diagnostics of SCLC is recommended by complementary ProGRP and NSE studies. The present work is a summary of the latest reports regarding diagnostic utility of these markers in SCLC.

Biomarkers along the continuum of care in lung cancer

Blood-based biomarkers are valuable diagnostic tools for the management of lung cancer patients. They support not only differential diagnosis and histological subtyping, but are also applied for estimation of prognosis, stratification for specific therapies, monitoring of therapy response, surveillance monitoring and early detection of residual or progressive disease. Early diagnosis of lung cancer in high risk populations (screening) is a promising future indication but poses high medical and economic challenges to marker performance. The five mostly used classical 'tumor markers' show characteristic profiles of sensitivity and specificity for non-small cell lung cancer (NSCLC) like cytokeratin 19-fragments (CYFRA 21-1), carcino-embryonic antigen (CEA) and squamous cancer cell antigen (SCCA) as well as for small cell lung cancer (SCLC) like progastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE). Combined use and pattern recognition approaches enable highly accurate diagnosis, subtyping and therapy monitoring. For the interpretation of serial measurements on an individual level, marker-specific algorithms have to be developed. So-called companion diagnostics identify druggable molecular changes in signaling pathways of tumor tissue that can be addressed by targeted therapies. New highly sensitive technologies enable the convenient and serial molecular characterization on circulating tumor DNA (ctDNA) in the blood, too. This approach is helpful when biopsies are not available and to overcome tumor molecular heterogeneity and plasticity. As only a portion of patients have such druggable molecular changes, future strategies will imply the combined use of classical and new ctDNA-based biomarkers to optimize the management of lung cancer patients during the course of disease.

Utility of proGRP as a tumor marker in the medullary thyroid carcinoma

Background:

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor caused by a malignant transformation in the parafollicular C-cells of the thyroid, where calcitonin (CT) is released. Nowadays the main tumor markers (TM) used in the diagnosis and follow-up of MTC patients are CT and carcinoembryonic antigen (CEA). Nonetheless, progastrin releasing peptide (proGRP) has been recently proposed as a TM useful in the MTC. Our aims were to investigate the release of proGRP in thyroid tumors, its role in the assessment of advanced MTC and its utility in the differential diagnosis between MTC and non-MTC thyroid tumors.

Methods:

Serum samples from 22 patients with MTC and 16 with non-MTC were collected. Patients were classified into advanced cancer or no evidence of disease (NED). ProGRP was performed by Architect (Abbot Diagnostics), CT by Liaison (Diasorin) and CEA by Cobas E601(Roche Diagnostics).

Results:

ProGRP median concentration in advanced MTC was significantly higher (1398.4 pg/mL) when compared with non-MTC, either in advanced disease (24.9 pg/mL) or NED (14.6 pg/mL). In non-MTC patients, proGRP median concentration was below its cutoff level (50 pg/mL). Similar to CT, proGRP was able to detect 88.9% of MTC patients, but with a slightly lower specificity of 76.9%. Using proGRP together with CT the sensitivity increased to 100%.

Conclusions:

The low prevalence of this malignancy strongly recommends further collaborative studies, mainly focused on monitoring proGRP during tyrosine kinase inhibitors treatment for early detection of resistance and assessing its usefulness to avoid the observed false positive fluctuations that occur with CT and CEA.

Clinically Meaningful Use of Blood Tumor Markers in Oncology

Before the introduction of modern imaging techniques and the recent developments in molecular diagnosis, tumor markers (TMs) were among the few available diagnostic tools for the management of cancer patients. Easily obtained from serum or plasma samples, TMs are minimally invasive and convenient, and the associated costs are low. Single TMs were traditionally used but these have come under scrutiny due to their low sensitivity and specificity when used, for example, in a screening setting. However, recent research has shown superior performance using a combination of multiple TMs as a panel for assessment, or as part of validated algorithms that also incorporate other clinical factors. In addition, newer TMs have been discovered that have an increased sensitivity and specificity profile for defined malignancies. The aim of this review is to provide a concise overview of the appropriate uses of both traditional and newer TMs and their roles in diagnosis, prognosis, and the monitoring of patients in current clinical practice. We also look at the future direction of TMs and their integration with other diagnostic modalities and other emerging serum based biomarkers, such as circulating nucleic acids, to ultimately advance diagnostic performance and improve patient management.

Assays for Qualification and Quality Stratification of Clinical Biospecimens Used in Research: A Technical Report from the ISBER Biospecimen Science Working Group

This technical report presents quality control (QC) assays that can be performed in order to qualify clinical biospecimens that have been biobanked for use in research. Some QC assays are specific to a disease area. Some QC assays are specific to a particular downstream analytical platform. When such a qualification is not possible, QC assays are presented that can be performed to stratify clinical biospecimens according to their biomolecular quality.

Progastrin-releasing peptide as a diagnostic and therapeutic biomarker of small cell lung cancer

BACKGROUND

Progastrin-releasing peptide (proGRP) is a recently identified biomarker of small cell lung cancer (SCLC). We evaluated the usefulness of plasma proGRP level as a tumor marker for diagnosis and treatment monitoring in patients with SCLC.

METHODS

Plasma samples were collected prospectively from 452 [212 non-small cell lung cancer (NSCLC), 105 SCLC, and 135 other diseases] patients who visited the hospital for tissue diagnosis. Plasma proGRP levels were measured using a two-step automated immunoassay.

RESULTS

The median proGRP level was significantly higher in patients with SCLC (892.7 pg/mL) than those with NSCLC (32.6 pg/mL, P<0.001) and other diseases (26.6 pg/mL, P<0.001). At cutoff level of 63 pg/mL, proGRP shows 85.7% sensitivity, 90.2% specificity, 72.5% positive predictive value and 95.4% negative predictive value in patients with SCLC. The area under the curve values were 0.93 for distinguishing SCLC from NSCLC, and 0.943 for distinguishing SCLC from the other conditions. Median proGRP level was higher in extensive disease (1,055.2 pg/mL) than limited disease (253.8 pg/mL, P=0.005). Median OS was significantly shorter in patients with extensive disease (6.0±0.7 months) than limited disease (12.7±4.5 months, P<0.01). Among the 39 patients with SCLC who were followed, the median proGRP levels of the 23 responders decreased after chemotherapy (P<0.001).

CONCLUSIONS

Plasma proGRP level could be a useful diagnostic and therapeutic monitoring biomarker for patients with SCLC and the initial level may help with SCLC tumor staging.

New ARCHITECT plasma pro-gastrin-releasing peptide assay for diagnosing and monitoring small-cell lung cancer

Background:

Progastrin-releasing peptide (ProGRP) is a potential marker for small-cell lung cancer (SCLC) in serum; however, it may be more stable in plasma. We investigated a new plasma assay (ProGRPp) and its usefulness in diagnosing and monitoring SCLC.

Methods:

The marker concentrations were determined on the ARCHITECT i system.

Results:

The assay could distinguish SCLC from non-small-cell lung cancer (NSCLC: area under the curve 0.931, 95% CI 0.893–0.969; cross-validated accuracy 0.813; sensitivity 84.0%, specificity 96.3% at 140 pg ml⁻¹ cutoff). The probability of SCLC when ProGRPp was >140 pg ml⁻¹ was 91.8%, after adjusting for age, gender, and renal dysfunction. The NSCLC patients with ProGRPp >140 pg ml⁻¹ were at high risk (odds ratio=37.0, P<0.001) for tumours with neuroendocrine features. False negatives in SCLC were associated with a lack of thyroid transcription factor-1 (P<0.001). A decrease of ProGRPp to <140 pg ml⁻¹ during chemotherapy was significantly associated with the image-based response (P<0.001), and independently affected progression-free survival (PFS, relative risk=2.51, P=0.04) and overall survival (OS, relative risk=4.38, P=0.003), after adjustment for imaging response, performance status, and stage.

Conclusions:

The ProGRPp assay is specific and sensitive for diagnosing SCLC. Changes in ProGRPp during chemotherapy are significantly associated with image-based response, PFS, and OS.

Circulating HMGB1 and RAGE as Clinical Biomarkers in Malignant and Autoimmune Diseases

High molecular group box 1 (HMGB1) is a highly conserved member of the HMG-box-family; abundantly expressed in almost all human cells and released in apoptosis; necrosis or by activated immune cells. Once in the extracellular space, HMGB1 can act as a danger associated molecular pattern (DAMP), thus stimulating or inhibiting certain functions of the immune system; depending on the “combinatorial cocktail” of the surrounding milieu. HMGB1 exerts its various functions through binding to a multitude of membrane-bound receptors such as TLR-2; -4 and -9; IL-1 and RAGE (receptor for advanced glycation end products); partly complex-bound with intracellular fragments like nucleosomes. Soluble RAGE in the extracellular space, however, acts as a decoy receptor by binding to HMGB1 and inhibiting its effects. This review aims to outline today’s knowledge of structure, intra- and extracellular functions including mechanisms of release and finally the clinical relevance of HMGB1 and RAGE as clinical biomarkers in therapy monitoring, prediction and prognosis of malignant and autoimmune disease.