Lung tumor markers of cytokeratin origin: an overview

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

In vitro vascularized immunocompetent patient-derived model to test cancer therapies

This work describes a patient-derived tumoroid model (PDTs) to support precision medicine in lung oncology. The use of human adipose tissue-derived microvasculature and patient-derived peripheral blood mononuclear cells (PBMCs) permits to achieve a physiologically relevant tumor microenvironment. This study involved ten patients at various stages of tumor progression. The vascularized, immune-infiltrated PDT model could be obtained within two weeks, matching the requirements of the therapeutic decision. Histological and transcriptomic analyses confirmed that the main features from the original tumor were reproduced. The 3D tumor model could be used to determine the dynamics of response to antiangiogenic therapy and platinum-based chemotherapy. Antiangiogenic therapy showed a significant decrease in vascular endothelial growth factor (VEGF)-A expression, reflecting its therapeutic effect in the model. In an immune-infiltrated PDT model, chemotherapy showed the ability to decrease the levels of lymphocyte activation gene-3 protein (LAG-3), B and T lymphocyte attenuator (BTLA), and inhibitory receptors of T cells functions.

Increased circulating cytokeratin 19 fragment levels in preterm neonates receiving mechanical ventilation are associated with poor outcome

Invasive mechanical ventilation and oxygen toxicity are postnatal contributors to chronic lung disease of prematurity, also known as bronchopulmonary dysplasia (BPD). Cyfra 21-1 is a soluble fragment of cytokeratin 19, which belongs to the cytoskeleton stabilizing epithelial intermediate filaments. As a biomarker of structural integrity, Cyfra 21-1 might be associated with airway injury and lung hypoplasia in neonates. Serum Cyfra 21-1 concentrations for 80 preterm and 80 healthy term newborns were measured within 48 h after birth. Preterm infants with the combined endpoint BPD/mortality had significantly higher Cyfra 21-1 levels compared with those without fulfilling BPD/mortality criteria (P = 0.01). Also, severe RDS (>grade III) was associated with higher Cyfra levels (P = 0.01). Total duration of oxygen therapy was more than five times longer in neonates with high Cyfra 21-1 levels (P = 0.01). Infants with higher Cyfra 21-1 values were more likely to receive mechanical ventilation (50% vs. 17.5%). However, the duration of mechanical ventilation was similar between groups. The median Cyfra value was 1.93 ng/mL (IQR: 1.68-2.53 ng/mL) in healthy term neonates and 8.5 ng/mL (IQR: 3.6-16.0 ng/mL) in preterm infants. Using ROC analysis, we calculated a Cyfra cutoff > 8.5 ng/mL to predict BPD/death with an AUC of 0.795 (P = 0.004), a sensitivity of 88.9%, and a specificity of 55%. Mortality was predicted with a cutoff > 17.4 ng/mL (AUC: 0.94; P = 0.001), a sensitivity of 100%, and a specificity of 84%. These findings suggest that Cyfra 21-1 concentration might be useful to predict poor outcome in premature infants.

Diagnostic potential of extracellular vesicle-associated microRNA-10b and tumor markers for lung adenocarcinoma

MicroRNAs (miRNAs/miRs) in extracellular vesicles (EVs) are potential diagnostic markers. The purpose of the present study was to investigate potential EV miRNA biomarkers for lung adenocarcinoma (LUAD). Potential miRNAs were identified by searching public databases and verified by examining clinical samples. The diagnostic value of EV-associated miR-10b, plasma miR-10b and tumor markers (TMs), including α-fetoprotein (AFP), neuron-specific enolase, carcinoembryonic antigen (CEA), cytokeratin 19 fragment 21-1 (CYFRA211), pro-gastrin-releasing-peptide, carbohydrate antigen (CA)125, CA153, CA199 and CA724, was evaluated via receiver operating characteristic curve analysis. By searching the Gene Expression Omnibus and The Cancer Genome Atlas databases, miR-10b was identified as a potential biomarker. The analysis of clinical samples suggested that EV-associated miR-10b from plasma was significantly differentially expressed between LUAD and control samples. EV-associated miR-10b could function as a diagnostic marker for LUAD, with an AUC of 0.998, which was higher than the AUCs for TMs such as AFP, CEA, CYFRA211, CA125, CA153, CA199, CA724, pro-gastrin-releasing-peptide and neuron-specific enolase. In conclusion, EV-associated miR-10b may be a potential diagnostic biomarker for LUAD that is superior to plasma miR-10b and TMs.

The Prognostic Value of Preoperative Serum Tumor Markers in Non-Small Cell Lung Cancer Varies With Radiological Features and Histological Types

Objectives

To assess the association between common-used serum tumor markers and recurrence of lung adenocarcinoma and squamous cell carcinoma separately and determine the prognostic value of serum tumor markers in lung adenocarcinoma featured as ground glass opacities.

Methods

A total of 2,654 non-small cell lung cancer patients undergoing surgical resection between January 2008 and September 2014 were analyzed. The serum levels of carcinoma embryonic antigen (CEA), cytokeratin 19 fragment (CYFRA21-1), neuron-specific enolase (NSE), carbohydrate antigen 125 (CA125), carbohydrate antigen 153 (CA153) and carbohydrate antigen 199 (CA199) were tested preoperatively. Survival analyses were performed with COX proportional hazard regression.

Results

Among patients with lung adenocarcinoma, elevated preoperative serum CEA(HR=1.246, 95%CI:1.043-1.488, P=0.015), CYFRA21-1(HR=1.209, 95%CI:1.015-1.441, P=0.034) and CA125(HR=1.361, 95%CI:1.053-1.757, P=0.018) were significantly associated with poorer recurrence free survival (RFS). Elevated preoperative serum CA199 predicted worse RFS in patients diagnosed with lung squamous cell carcinoma (HR=1.833, 95%CI: 1.216-2.762, P=0.004). Preoperative serum CYFRA21-1(HR=1.256, 95%CI:1.044-1.512, P=0.016) and CA125(HR=1.373, 95%CI: 1.050-1.795, P=0.020) were independent prognostic factors for patients with adenocarcinoma presenting as solid nodules while serum CEA (HR=2.160,95%CI:1.311-3.558, P=0.003) and CA125(HR=2.475,95%CI:1.163-5.266, P=0.019) were independent prognostic factors for patients with adenocarcinoma featured as ground glass opacities.

Conclusions

The prognostic significances of preoperative serum tumor markers in non-small cell lung cancer were associated with radiological features and histological types.

Serum SCCA, Cyfra 21–1, EGFR and Cyclin D1 Levels in Patients with Oral Squamous Cell Carcinoma

Objectives

To determine the concentrations of SCCA, Cyfra 21–1, EGFR and Cyclin D1 in serum of patients with oral squamous cell carcinoma, and investigate their diagnostic value and their relationship with clinical stage, histological differentiation and lymph node metastasis.

Methods

Seventy hospitalized patients with oral squamous cell carcinoma and 72 healthy individuals were included in the study. Venous blood was collected from all study participants, in the oral carcinoma patients before tumor resection. One week after surgery, venous blood was collected again from 20 patients. Serum marker levels were determined by enzyme-linked immunosorbent assay (ELISA).

Results

The serum SCCA, EGFR and Cyclin D1 concentrations were significantly higher in patients with oral squamous cell carcinoma than in healthy controls, while there was no significant difference in Cyfra 21–1 levels between patients and controls. The serum SCCA concentration decreased after surgery, but there was no significant difference in the serum Cyfra 21–1, EGFR and Cyclin D1 concentrations before and after surgery. Serum SCCA, Cyfra 21–1, EGFR and Cyclin D1 concentrations were not correlated with clinical stage, histological differentiation and lymph node metastasis. When SCCA, EGFR and Cyclin D1 were measured separately, EGFR had the highest diagnostic sensitivity and accuracy and Cyclin D1 had the highest specificity; when any two of the markers were tested in combination, the combined detection of EGFR and Cyclin D1 had the highest sensitivity, specificity and accuracy.

Conclusions

SCCA, EGFR and Cyclin D1 may prove to be useful tumor markers in oral squamous cell carcinoma. The combined determination of EGFR and Cyclin D1 may be of value in the diagnosis of oral squamous cell carcinoma. Serum SCCA may be used as an adjunct in monitoring treatment response.

Biosensors Incorporating Bimetallic Nanoparticles

This article presents a review of electrochemical bio-sensing for target analytes based on the use of electrocatalytic bimetallic nanoparticles (NPs), which can improve both the sensitivity and selectivity of biosensors. The review moves quickly from an introduction to the field of bio-sensing, to the importance of biosensors in today's society, the nature of the electrochemical methods employed and the attendant problems encountered. The role of electrocatalysts is introduced with reference to the three generations of biosensors. The contributions made by previous workers using bimetallic constructs, grouped by target analyte, are then examined in detail; following which, the synthesis and characterization of the catalytic particles is examined prior to a summary of the current state of endeavor. Finally, some perspectives for the future of bimetallic NPs in biosensors are given.

Prognostic and predictive biomarkers in early stage NSCLC: CTCs and serum/plasma markers

Resection of early stage non-small cell lung cancer (NSCLC) offers patients the best hope of cure, however recurrence rates post-resection remain high suggesting the presence of micro-metastatic disease at the time of surgery undetected by standard staging methods. A critical step in the metastatic cascade is the entry of tumor cells into the circulation enabling their distribution to and seeding of distant organs. This review explores the evidence for predictive and prognostic circulating biomarkers in the early stage NSCLC population. We summarize studies that have explored a variety of targets including circulating proteins, nucleic acids and more recently circulating tumor cells (CTCs) as potentially clinically relevant biomarkers in the early stage setting. Circulating biomarkers may add clinically relevant information about the biological behavior of tumors over and above that provided by pathological staging. Improvement in the stratification of patients according to the likelihood of metastatic relapse after radical treatments such as surgical resection could allow more effective targeting of systemic therapies such as adjuvant chemotherapy.

Lung Cancer Biomarkers

Lung cancer is the most frequently occurring cancer in the world and continually leads in mortality among cancers. The overall 5-year survival rate for lung cancer has risen only 4% (from 12% to 16%) over the past 4 decades, and late diagnosis is a major obstacle in improving lung cancer prognosis. Survival of patients undergoing lung resection is greater than 80%, suggesting that early detection and diagnosis of cancers before they become inoperable and lethal will greatly improve mortality. Lung cancer biomarkers can be used for screening, detection, diagnosis, prognosis, prediction, stratification, therapy response monitoring, and so on. This review focuses on noninvasive diagnostic and prognostic biomarkers. For that purpose, our discussion in this review will focus on biological fluid-based biomarkers. The body fluids include blood (serum or plasma), sputum, saliva, BAL, pleural effusion, and VOC. Since it is rich in different cellular and molecular elements and is one of the most convenient and routine clinical procedures, serum or plasma is the main source for the development and validation of many noninvasive biomarkers. In terms of molecular aspects, the most widely validated ones are proteins, some of which are used in the clinical sector, though in limited accessory purposes. We will also discuss the lung cancer (protein) biomarkers in clinical trials and currently in the validation phase with hundreds of samples. After proteins, we will discuss microRNAs, methylated DNA, and circulating tumor cells, which are being vigorously developed and validated as potential lung cancer biomarkers. The main aim of this review is to provide researchers and clinicians with an understanding of the potential noninvasive lung cancer biomarkers in biological fluids that have recently been discovered.

Tissue Expression of Low and High Molecular Weight Cytokeratins in Lung Carcinoma Sections: Its Correlation with Some Clinic-Pathological Features

The tissue expression of low (LMW) and high (HMW) molecular weight cytokeratins and Ber-EP4 antigen in both small (SCLC) and non-small (NSCLC) cell lung carcinomas, as well as its correlation with a variety of clinic-pathological features, was evaluated. In general, 43/52 (82.7%) of NSCLC sections showed the expression of at least one type of cytokeratin while only 7/16 (43.7%) of SCLC were stained with both LMW cytokeratin and pan-cytokeratins antibodies. Remarkably, 18/52 (34.6%) of NSCLC were positive to both types of cytokeratins. However, none of SCLC showed this pattern of expression. In NSCLC patients, the increasing levels of HMW cytokeratins expression, as shown by 34βE12 antibody, correlated with the occurrence of disease recurrence (P=0.0057; Fisher’s exact test). Consequently, the expression of HMW cytokeratins was found to be associated with a poor 4-year overall survival of NSCLC patients (P=0.0315; Log rank test), not taking into account the histopathological classification of tumors. Similar results were obtained when 8-year overall survival was assessed (P=0.0103; Log rank test). Our results could suggest the assessment of HMW cytokeratins in a larger series of NSCLC samples in order to confirm the potential prognostic value of them.

Clinical diagnostic utility of CA 15-3 for the diagnosis of malignant pleural effusion: A meta-analysis

Malignant pleural effusion (MPE) is one of the most common pleura-associated conditions observed in clinical practice. The development of MPE usually defines advanced cancer with a poor prognosis. Carbohydrate antigen 15-3 (CA 15-3), as an effective pleural fluid biomarker, has been an object of ongoing research in the detection of MPE. The aim of this meta-analysis was to establish the overall diagnostic accuracy of the measurement of pleural CA 15-3 for diagnosing MPE. The databases Medline (using PubMed as the search engine), Embase, Ovid, Web of Science and Cochrane database (up to December 2013) were searched to identify relevant studies. No lower date limit was applied. All literature published in English was reviewed. Sensitivity, specificity, likelihood ratio and diagnostic odds ratio (DOR) were pooled using a random-effect model. Summary receiver operating characteristic (SROC) curve analysis was conducted to evaluate the overall diagnostic value. The methodological quality was assessed in line with the Quality Assessment for Studies of Diagnostic Accuracy statement. Twenty-one studies with a total of 2,861 cases were included in present meta-analysis. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and DOR of CA 15-3 in the diagnosis of MPE were 0.58 [95% confidence interval (CI), 0.56–0.61], 0.91 (95% CI, 0.90–0.93), 8.93 (95% CI, 4.45–17.93), 0.46 (95% CI, 0.37–0.56) and 24.89 (95% CI, 10.39–59.63), respectively. In addition, the area under the curve (AUC) was 0.84. In conclusion, due to the significantly high specificity of pleural CA 15-3 in detecting MPE, it may play a pivotal role in screening to identify patients who may benefit from further invasive pathologic examination, particularly in those presenting clinical manifestations of MPE but with negative cytological findings of the pleural fluid. However, ruling out MPE by testing CA15-3 alone is not recommended due to its limited sensitivity, and it is recommended that the results of CA15-3 assays are interpreted in parallel with conventional test results and other clinical findings.

Evaluation of tumor markers carcinoembryonic antigen, cytokeratin 19 fragment and cancer-associated antigen 72-4 in neoplastic and non-neoplastic canine effusions differentiation

The concentration of tumor markers in body fluids can be used for diagnosis and prognosis of patients. This study aimed to investigate the performance of tumor markers cytokeratin 19 fragment (CYFRA 21-1), cancer-associated antigen 72-4 (CA 72-4) and carcinoembryonic antigen (CEA) in the neoplastic and non-neoplastic canine effusions. In thirty-two neoplastic (n=16) and non-neoplastic (n=16) samples of canine thoracic or abdominal effusions, tumor markers were measured. Significant statistical difference was found only for the CYFRA 21-1 marker. The levels were significantly higher for the neoplastic group. The lack of significance between groups for markers CA 72-4 and CEA can be explained by the presence of other diseases in the non-neoplastic group, causing elevated levels of these markers. This study concludes that CYFRA 21-1 performed well, showing good sensitivity, specificity and accuracy in the diagnosis of neoplastic effusions in dogs. However, further investigations are necessary in patients with malignancy as those with benign effusions.

Significance of tumor markers in lung cancer

The objective was to test the utility of the cytokeratins CYFRA 21-1, tissue polypeptide specific antigen (TPS), Neuron specific enolase (NSE) and Carcino Embryonic antigen (CEA) in patients with lung cancer and in the pleural fluid of the patients with lung cancer and also the predicting ability of these tumor markers with respect to the histological types [including non small cell lung cancer (NSCLC) and small cell lung cancer (SCLC)] and pathological stages. 40 normal subjects and 222 cases of histological proven lung cancer were studied. The findings suggest that TPS and CYFRA 21-1, are useful serum markers for the diagnosis of NSCLC and NSE seems to be useful tumor marker for monitoring course of patients especially SCLC. The combined use of these cytokeratin markers TPS and CYFRA 21-1 may provide additional information for prognosis.

LC/LC-MS/MS of an innovative prostate human epithelial cancer (PHEC) in vitro model system

This work describes the proteomic characterization of a novel in vitro prostate cancer model system, the clonal prostatic human epithelial cancer (PHEC) cell lines. The model is composed of three cell lines representing the three progressive cancer states found in vivo: non-tumorigenic, tumorigenic, and metastatic. The cell lines were evaluated for differential protein expression between states using two dimensional liquid:liquid chromatographic separation followed by mass spectral identification. The proteins from cellular extracts were first separated using liquid:liquid primary separation based on their isoelectric points and hydrophobicity. The resulting peptide fractions were applied to liquid chromatography-mass spectrometry (LC-MS) separation for mass determination and protein identification based on Mascot database inquiry. Over 200 proteins that change expression over the course of progression of this in vitro prostate cancer model were discovered during the comparative analysis of the three cell lines. The importance of these proteins on prostate cancer progression remains to be elucidated with further characterizations. The combination of the two dimensional liquid:liquid separation and mass spectral identifications was used to successfully analyze differential protein expression between multiple cell lines.

Decline of serum CYFRA21-1 during chemoradiotherapy of NSCLC: a probable predictive factor for tumor response

We investigated the predictive value of decline in the serum levels of tumor markers on tumor response during the chemoradiotherapy (CRT) in patients with non-small cell lung cancer (NSCLC). The serum levels of cytokeratin 19 fragment antigen 21-1 (CYFRA21-1), neurone-specific enolase and carcinoembryonic antigen were measured by enzyme-linked immunosorbent assays, while the tumor responses were assessed according to the World Health Organization response criteria. The relationship between the changes of serum level of tumor markers and the radiologic response were analyzed. The effective rates (CR + PR) in CYFRA21-1 (pretreatment serum level) high and low groups were 45.8% (33/72) and 66.7% (24/36), respectively (p=0.032). Independent sample t test showed that the relationship between the response of CYFRA21-1 and the radiologic objective response are significantly different (p=0.008). The best cutoff value of the decline ratio of CYFRA21-1 was established as 18.48% by ROC curve. CYFRA 21-1 responses appeared to be reliable surrogate markers to predict chemoradiotherapy efficacy in patients with NSCLC, an average drop of 18.48% in serum CYFRA21-1 appears to provide the predictive information for the sensitivity of CRT.

Elevated serum levels of TPS and CYFRA 21-1 predict poor prognosis in advanced non-small-cell lung cancer patients treated with gefitinib

Serum concentrations of tissue polypeptide-specific antigen (TPS) and Cytokeratin-19-Fragments (CYFRA 21-1) before operation or chemotherapy have been proved to be a useful prognostic tool for patients with NSCLC, but the related data for advanced NSCLC patients treated with gefitinib are limited. We retrospectively reviewed 122 advanced NSCLC patients treated with gefitinib between April 2002 and August 2007. Multiple clinical factors including pretreatment serum levels of TPS and CYFRA 21-1, age, gender, performance status (PS), smoking history, stage, histology, the number of prior chemotherapy and the patients' clinical outcomes were analyzed. Patients without elevated serum TPS levels had a more RR (36.8%) than those with elevated serum TPS levels (18.5%) (P = 0.023), nevertheless, a similar result was not seen in patients with normal CYFRA 21-1 levels. For patients with normal vs. high TPS levels, the median survival times (MSTs) were 15.9 vs. 7.3 months (P = 0.001). For patients with normal vs. high CYFRA 21-1, the MSTs were 15.4 vs. 7.5 months (P = 0.003). Moreover, for patients with both elevated, vs. one elevated and both normal TPS and CYFRA 21-1 levels, the MSTs were 5.4 vs. 11.4 months (P = 0.001), and 16.5 months (P < 0.001), respectively. In multivariate analysis, TPS (P = 0.001) and CYFRA 21-1 (P = 0.005) alone or combination (P < 0.001) remained significant correlation to survival. In NSCLC patients with gefitinib therapy, pretreatment serum levels of TPS and CYFRA 21-1 alone or combined might be independent prognostic factors, and the pretreatment serum TPS level may predict the tumor response.

Platelet linoleic acid is a potential biomarker of advanced non-small cell lung cancer

New parameters that could be used as tumor markers for lung cancer would be valuable. Our aim was to analyze the fatty acid profiles of total lipids from erythrocytes and platelets from patients with advanced non-small cell lung cancer (NSCLC), chronic obstructive pulmonary disease (COPD) and asthma to reveal the fatty acids that could be used as NSCLC biomarkers. In our study, 50, 15 and 15 patients with advanced NSCLC, COPD and asthma and 50 healthy subjects were enrolled. Fatty acid profiles were investigated using gas chromatography/mass spectrometry followed by ROC (receiver operating characteristics) curves analysis to gain information about biomarkers. Sialic acid (SA) and cytokeratins were measured by the thiobarbituric acid and immunoradiometric methods respectively. Useful fatty acid markers were as follows: erythrocytes, 22:0 and linoleic acid (LA, 18:2n6); platelets, 16:0, 18:0, and LA. At the cutoff value to obtain maximum accuracy, the best biomarker was platelet LA, with higher diagnostic yields than the commonly used markers SA or cytokeratins (100%, 76%, 75% and 86% sensitivity, specificity, positive predictive value and accuracy, respectively). These findings suggest that platelet LA might be used as a biomarker of NSCLC in relation to different aspects of the disease process that now needs to be explored.

Drug-selected human lung cancer stem cells: cytokine network, tumorigenic and metastatic properties

Background

Cancer stem cells (CSCs) are thought to be responsible for tumor regeneration after chemotherapy, although direct confirmation of this remains forthcoming. We therefore investigated whether drug treatment could enrich and maintain CSCs and whether the high tumorogenic and metastatic abilities of CSCs were based on their marked ability to produce growth and angiogenic factors and express their cognate receptors to stimulate tumor cell proliferation and stroma formation.

Methodology/Findings

Treatment of lung tumor cells with doxorubicin, cisplatin, or etoposide resulted in the selection of drug surviving cells (DSCs). These cells expressed CD133, CD117, SSEA-3, TRA1-81, Oct-4, and nuclear β-catenin and lost expression of the differentiation markers cytokeratins 8/18 (CK 8/18). DSCs were able to grow as tumor spheres, maintain self-renewal capacity, and differentiate. Differentiated progenitors lost expression of CD133, gained CK 8/18 and acquired drug sensitivity. In the presence of drugs, differentiation of DSCs was abrogated allowing propagation of cells with CSC-like characteristics. Lung DSCs demonstrated high tumorogenic and metastatic potential following inoculation into SCID mice, which supported their classification as CSCs. Luminex analysis of human and murine cytokines in sonicated lysates of parental- and CSC-derived tumors revealed that CSC-derived tumors contained two- to three-fold higher levels of human angiogenic and growth factors (VEGF, bFGF, IL-6, IL-8, HGF, PDGF-BB, G-CSF, and SCGF-β). CSCs also showed elevated levels of expression of human VEGFR2, FGFR2, CXCR1, 2 and 4 receptors. Moreover, human CSCs growing in SCID mice stimulated murine stroma to produce elevated levels of angiogenic and growth factors.

Conclusions/Significance

These findings suggest that chemotherapy can lead to propagation of CSCs and prevention of their differentiation. The high tumorigenic and metastatic potentials of CSCs are associated with efficient cytokine network production that may represent a target for increased efficacy of cancer therapy.

Proteomic analysis of lamellar bodies isolated from rat lungs

Background

Lamellar bodies are lysosome-related secretory granules and store lung surfactant in alveolar type II cells. To better understand the mechanisms of surfactant secretion, we carried out proteomic analyses of lamellar bodies isolated from rat lungs.

Results

With peptide mass fingerprinting by Matrix Assisted Laser Desorption/Ionization – Time of Flight mass spectrometry, 44 proteins were identified with high confidence. These proteins fell into diverse functional categories: surfactant-related, membrane trafficking, calcium binding, signal transduction, cell structure, ion channels, protein processing and miscellaneous. Selected proteins were verified by Western blot and immunohistochemistry.

Conclusion

This proteomic profiling of lamellar bodies provides a basis for further investigations of functional roles of the identified proteins in lamellar body biogenesis and surfactant secretion.

Erythrocyte and platelet phospholipid fatty acids as markers of advanced non-small cell lung cancer: comparison with serum levels of sialic acid, TPS and Cyfra 21-1

The phospholipid fatty acid profiles of erythrocytes and platelets from fifty patients with advanced non-small cell lung cancer were investigated using gas chromatography/mass spectrometry, followed by "ROC" curves analysis to gain novel biomarker information. Sialic acid and cytokeratins were also examined. Potentially useful fatty acid markers: Erythrocytes: phosphatidylcholine, 18:2n6 and 20:4n6; phosphatidylethanolamine, 22:4n6 and 22:6n3 + 24:1n9. Platelets: phosphatidylcholine, 22.0; phosphatidylethanolamine, 22:5n3 + 24:0. At the cut-off value to obtain maximum accuracy, the best biomarkers were found in platelets: phosphatidylserine + phosphatidylinositol (PS + PI), 21:0; sphyngomyelin: 20:1n9 and 22:1n9. All these fatty acids showed similar/higher diagnostic yields than the commonly used markers sialic acid or cytokeratins.

Evaluation of serum and pleural levels of the tumor markers CEA, CYFRA21-1 and CA 15-3 in patients with pleural effusion

OBJECTIVE

To determine the levels of the tumor markers carcinoembryonic antigen (CEA), cytokeratin 19 fragment (CYFRA21-1) and carbohydrate antigen 15-3 (CA 15-3) in the blood and pleural fluid of patients with benign or malignant pleural effusion, evaluating the sensitivity of each marker in these fluids.

METHODS

We prospectively evaluated 85 patients with pleural effusion. The study of the pleural fluid observed the criteria established in the literature. Levels of the markers were determined using electrochemiluminescence. The sensitivity was determined on the condition that the specificity was > or = 90%.

RESULTS

Of the 85 cases, 36 (42.4%) were malignant, 30 (35.3%) were benign, and the results were inconclusive in 19 (22.3%). In the malignant cases, the CEA and CYFRA21-1 levels were higher in the pleural fluid than in the blood, which was not observed for CA 15-3. In the benign cases, the CYFRA21-1 levels were higher in the pleural fluid than in the blood, whereas the opposite was found for CEA and CA 15-3. There were significant differences between malignant and benign cases for all markers, in pleural fluid and blood. In the pleural fluid, the sensitivity of CEA, CYFRA21-1 and CA 15-3 was 69.4, 69.4 and 66.7%, respectively, and the combined sensitivity was 80.6%. In the blood, the sensitivity was 57.1%, 71.4% and 48.6% for CEA, CYFRA21-1 and CA 15-3, respectively, and the combined sensitivity was 77%.

CONCLUSION

The results suggest that these markers might be useful in the differentiation between malignant and benign pleural effusion.

Detection of epithelial cell death in the body by cytokeratin 18 measurement

Cell death is as important as cell division in both physiological and pathological processes. Three major types of cell death have been described: apoptosis, autophagy and necrosis. Apoptosis is a form of programmed cell death, mediated by caspases. Autophagy is an evolutionarily conserved process involving lysosomes, implicated in both cell survival and death. Necrosis is believed to be an unregulated process, followed by release of intracellular components. The epithelial-specific intermediate filament cytokeratin 18 (Kl8) has different fates depending on the type of cell death. During apoptosis, K18 is cleaved at two sites into three fragments, one of which is specifically recognized by the monoclonal antibody, M30. During autophagy K18 is reported to stay uncleaved. Necrotic cells are considered to release K18. Thus, serum levels of different forms of K18 would reflect the type of cell death occurring in the body. Two enzyme-linked immunosorbent assays have been developed: one for the cleaved fragments of K18 and the other for total K18. Detection of serum levels of cleaved and total K18 showed that the ratios between cleaved and total K18 were highly variable among patients with endometrial cancer. Monitoring serum levels of cleaved and total K18 during chemotherapy showed an association between increases in total K18 levels and clinical responses. Monitoring serum levels of K18 may be a promising approach for early detection of therapeutic effects and the levels of different forms of K18 might indicate the mode of cell death occurring in the body.

Newly developed assay measuring cytokeratins 8, 18 and 19 in serum is correlated to survival and tumor volume in patients with esophageal carcinoma

Esophageal carcinoma is the seventh most common cause of cancer-related death in the Western world. In Sweden, approximately 400 new esophageal carcinomas are diagnosed yearly. Cytokeratins (CK) are specific for epithelial cells and the expression profile usually remains unchanged even when the epithelium undergoes malignant transformation. In the present study, MonoTotal, a newly developed RIA-assay detecting circulating CK 8, 18 and 19 fragments, was investigated in sera from patients with esophageal carcinoma. Serum samples from 40 patients with esophageal carcinoma were collected. The median value of circulating CK 8, 18 and 19 measured with MonoTotal was 378 U/L (range 53-6843) and with regard to the defined cut-off (< 75 U/L), 39/40 (98%) patients were shown to have elevated levels of circulating CK 8, 18 and 19. Patients with localized disease had a median value of circulating CK 8, 18 and 19 of 305 U/L (mean: 500 U/L), whereas the corresponding value for metastatic disease was 771 U/L (mean: 1506 U/L). This difference was statistically significant (P = 0.016). Circulating CK 8, 18 and 19, according to cut-off, were not associated with survival in univariate analysis (P = 0.34). However, continuous values of circulating levels of CK 8, 18 and 19 were associated with survival (P = 0.000083) in univariate as well as in the multivariate analysis (P = 0.03). In conclusion, circulating CK 8, 18 and 19 correlates with increased tumor burden and might, in conjunction with other clinical parameters, aid the clinician in estimating the prognosis of the individual patient.

Using protein microarray as a diagnostic assay for non-small cell lung cancer

RATIONALE

Phenotypic and genotypic heterogeneity of lung cancer likely precludes the identification of a single predictive marker and suggests the importance of identifying and measuring multiple markers.

OBJECTIVES

We describe the use of a fluorescent protein microarray to identify and measure multiple non-small cell lung cancer-associated antibodies and show how simultaneous measurements can be combined into a single diagnostic assay.

METHODS

T7 phage cDNA libraries of non-small cell lung cancer were first biopanned with plasma samples from normal subjects and patients with non-small cell lung cancer to enrich the component of tumor-associated proteins, and then applied to microarray slides. Two hundred twelve immunogenic phage-expressed proteins were identified from roughly 4,000 clones, using high-throughput screening with patient plasmas and assayed with 40 cancer and 41 normal plasma samples. Twenty patient and 21 normal plasma samples were randomly chosen and used for statistical determination of the predictive value of each putative marker. Statistical analysis identified antibody reactivity to seven unique phage-expressed proteins that were significantly different (p < 0.01) between patient and normal groups. The remaining 20 patient and 20 normal plasma samples were used as an independent test of the predictive ability of the selected markers.

MAIN RESULTS

Measurements of the 5 most predictive phage proteins were combined in a logistic regression model that achieved 90% sensitivity and 95% specificity in prediction of patient samples, whereas leave-one-out statistical analysis achieved 88.9% diagnostic accuracy among all 81 samples.

CONCLUSION

Our data indicate that antibody profiling is a promising approach that could achieve high diagnostic accuracy for non-small cell lung cancer.

Culture of feline corneal epithelial cells and infection with feline herpesvirus-1 as an investigative tool

OBJECTIVE

To isolate and characterize pure cultures of feline corneal epithelial cells and to assess the extent and nature of feline herpesvirus (FHV)-1 infection in these cells.

SAMPLE POPULATION

Healthy eyes from 23 recently euthanatized cats.

PROCEDURE

Stroma and epithelium of the rostral portion of the cornea were surgically isolated, and epithelial cells were detached from the stroma by enzymatic incubation. Epithelial cells were cultured in hormone-supplemented media. Cells were passaged, and cytokeratin expression was assessed. Cells were then infected with FHV-1, and cytopathic effects were determined.

RESULTS

Cell cultures were readily established from samples obtained from each eye and could be maintained through 6 passages. Cultured cells expressed cytokeratins 3 and 12 but not other cytokeratins. Infection with FHV-1 was rapid and caused widespread cytopathic effects.

CONCLUSIONS AND CLINICAL RELEVANCE

Feline corneal cells cultured in vitro during multiple passages maintain consistent morphologic characteristics and intermediate filament expression. They are susceptible to infection with FHV-1 and may provide a useful in vitro model for investigation of ocular drugs.

Biomarkers in non-small cell lung cancer prevention

Identification of biomarkers is one of the most promising approaches for the detection of early malignant or even premalignant lesions with the chance of diagnosing early stages of non-small cell lung cancer that could be treated curatively. Alterations of chromosomes (3p, 5q, 9p), genes (Rb, C-myc, C-mos, hTERT), proteins (p16, p53, K-ras, hnRNP A2/B1, MCM2, EGFR, erbB-2, erbB-3, erbB-4) and others can be found in lung cancer. Some of these occur at early stages of the disease and few could serve as potential screening markers. The actual literature is reviewed and the relevance of the different biomarkers for early lung cancer detection is discussed.

Apoptotic markers in cancer

In cancer, apoptotic processes occur both spontaneously and induced by antitumor therapies. Qualitative and quantitative changes in cancer cell death along with proliferative alterations are essential determinants in the pathogenesis and progression of malignant disease and its responsiveness to therapy. Besides detecting apoptosis by invasive means in tumor tissue, apoptotic products can be quantified in the circulation. Although circulating apoptotic products usually lack organ and tumor specificity, they contribute in the assessment of disease extent or aggressiveness. The ease of drawing blood facilitates the serial measurement of circulating apoptotic markers to monitor antitumor treatment and predict early response to therapy. This review describes the features of apoptotic and necrotic cell death along with the role the balance between the rates of cell death and cell proliferation plays in the progression of malignancy. The intracellular pathways mediating apoptosis are next summarized. The focus then shifts to the apoptotic markers found in the circulation and their diagnostic, prognostic, predictive, and management utility in cancer.

The Prospect of Biologic Staging of Non–Small-Cell Lung Cancer

The reductionistic approach to cancer research has led to an enormous amount of information and publications regarding the molecular biologic processes that take place in cancer tissue. However, the specific influence of this information on clinical practice has been limited. With the advent of new reductionistic tools like the transcriptomic and proteomic technologies, many would argue that further advances in the field of lung cancer research will be dominated by advances on the technical level. However, we anticipate that the most revolutionary advances will be those at a conceptual level. Medical science has always been reductionistic in essence, reducing and analyzing the composing elements of our complex biologic machinery, overlooking the fact that the interrelation among a set of simple determinants creates a new dimension of characteristics and functions. Problems emerging from a reductionistic approach are heterogeneity and variability. This review addresses the current conceptual problems in the field of lung cancer biology and provides a new conceptual model based on recent publications.

Serum levels of tissue polypeptide specific antigen are correlated with hepatocyte cytokeratin expression in alcoholic liver disease

BACKGROUND

Serum levels of the tumor marker tissue polypeptide specific antigen (TPS, cytokeratin 18 fragments) are increased in patients with alcoholic liver disease, particularly in cases of alcoholic hepatitis. Mallory bodies, characteristic of alcoholic hepatitis, are cytokeratin 8 and 18 aggregates. The study was aimed at investigating the possible relationship of serum TPS levels with hepatocyte cytokeratin expression in patients with alcoholic liver disease.

METHODS

Twenty-four patients with alcoholic liver disease were studied. Immunohistochemical staining for cytokeratins 8 and 18 was performed in liver specimens by means of CAM 5.2 monoclonal antibody. The number of hepatocytes containing CAM 5.2-reactive cytokeratin inclusions was compared with serum TPS levels.

MAIN RESULTS AND CONCLUSIONS

The vast majority of alcoholics (95%) showed increased (>100 units/liter) serum TPS levels. Serum TPS levels were significantly correlated with the number of hepatocyte cytokeratin inclusions. Serum TPS levels can predict hepatocyte cytokeratin expression in patients with alcoholic liver disease.

Clinical equivalence of two cytokeratin markers in mon-small cell lung cancer: a study of tissue polypeptide antigen and cytokeratin 19 fragments

STUDY OBJECTIVES

We have longstanding experience with tissue polypeptide antigen (TPA), a tumor marker of the cytokeratin (CK) family. In the mid-1990s, a new CK marker, CK 19 fragments (CYFRA 21-1), became popular and widely accepted. This is the first study specifically designed to compare the two markers.

DESIGN

Analysis of a single institution database over a 3-year period (ie, 1998 to 2000).

SETTING

Community-based hospital and second referral level institution for a province of 500,000 people.

PATIENTS

The study included 180 new consecutive patients (143 men) with pathologically documented non-small cell lung cancer (NSCLC), who were observed during and after treatment, and eventually were assessed for status.

INTERVENTIONS

Anthropometric, clinical, and laboratory data, including TPA and CYFRA 21-1 serum levels, were recorded prospectively. Standard nonparametric tests, Kaplan-Meyer survival analyses, Cox proportional hazards models, receiver-operating characteristic (ROC) curves, and estimates were used for statistical analysis.

MEASUREMENTS AND RESULTS

A total of 1,299 twin TPA and CYFRA 21-1 serum assays (180 performed at diagnosis and 1,119 performed during or after treatment) were obtained. Intermarker correlation tests revealed incredibly high Spearman rho indexes, ranging from 0.935 at diagnosis to 0.813 to 0.921 at the different follow-up times. The substantial equivalence of the two tests explained all the other results, as follows: their similar profile of correlation with the other variables (objective treatment response: TPA rho, 0.456; CYFRA 21-1 rho, 0.463; follow-up performance status: rho range, 0.424 to 0.435); their superimposable capability to predict important clinical situations (eg, recognizing a metastatic disease at diagnosis with areas under the ROC curve of 0.742 and 0.706, respectively); their nearly identical prognostic significance (the D statistic of the goodness-of-fit of a multivariate survival model: TPA, 851.0; CYFRA 21-1, 851.6).

CONCLUSIONS

In most of their traditional clinical applications the two serum tests are equivalent because of their virtual identity. We strongly recommend using a CK test in the evaluation of each NSCLC patient. The choice between TPA and CYFRA 21-1 can be based on nonclinical factors, such as the laboratory experience or preference, and the cost of the two kits.

Clinical relevance of molecular markers in lung cancer

The last two decades have seen an exponential growth of our knowledge on the molecular biology of cellular processes and neoplastic transformation. There is high expectation that these advances will be translated into further improvement in the care of cancer patients, especially in the areas of prevention, diagnosis and treatment. Realizing that the histopathological classification of lung cancer has reached its limit in providing additional critical information to further improve treatment strategy, numerous molecular aberrations occurring in lung cancers have been explored as potential new diagnostic markers and markers for molecular sub-staging. Despite extensive studies, most results remain largely controversial. This manuscript will briefly review molecular/genetic changes that have been investigated as candidate diagnostic, prognostic and predictive markers and as biomarkers for early detection in lung cancer. A more concerted and global approach to study the clinical relevance of molecular changes in lung cancers is required in the future.

Lung tumour markers in oncology practice: a study of TPA and CA125

Several substances mark the course of lung cancer and may reliably help the clinician in decision-making. This is the first clinical study specifically designed to compare tissue polypeptide antigen and CA 125 tumour associated antigen. Three hundred and eighty-four new lung cancer patients (309 males) were studied at their first clinical presentation and then strictly followed-up. Anthropometric, clinical and laboratory data - including tissue polypeptide antigen and CA 125 tumour associated antigen serum levels - were prospectively recorded. A total of 1000 tissue polypeptide antigen and CA 125 tumour associated antigen serum assays (384 pre-treatment and 616 posttreatment assays) were performed. Both tissue polypeptide antigen and CA 125 tumour associated antigen correlated significantly with the T, N and M stage descriptors at diagnosis (Rho: 0.200, 0.203, 0.263 and 0.181, 0.240, 0.276, respectively), and then with the objective response to treatment (Rho: 0.388 and 0.207, respectively). A pleural neoplastic involvement was mainly associated to an increase of CA 125 tumour associated antigen (Rho: 0.397). Both tissue polypeptide antigen and CA 125 tumour associated antigen were strongly predictive of the patients' outcome, as assessed by the univariate analysis of survival (log-rank test: 37.24 and 29.01) and several Cox' proportional hazards regression models. The two marker tests are similarly helpful and appear complementary, given the low inter-marker correlation and their independent prognostic capability.