Usefulness of monitoring the circulating Krebs von den Lungen-6 levels to predict the clinical outcome of patients with advanced nonsmall cell lung cancer treated with epidermal growth factor receptor tyrosine kinase inhibitors

Research progress of KL-6 in respiratory system diseases

This article comprehensively elucidates the discovery of Krebs von den Lungen-6 (KL-6), its structural features, functional mechanisms, and the current research status in various respiratory system diseases. Discovered in 1985, KL-6 was initially considered a tumor marker, but its elevated levels in interstitial lung disease (ILD) led to its recognition as a relevant serum marker for ILD. KL-6 is primarily produced by type 2 alveolar epithelial cell regeneration. Over the past 30 years since the discovery of KL-6, the number of related research papers has steadily increased annually. Following the coronavirus disease 2019 (COVID-19) pandemic, there has been a sudden surge in relevant literature. Despite KL-6's potential as a biomarker, its value in the diagnosis, treatment, and prognosis varies across different respiratory diseases, including ILD, idiopathic pulmonary fibrosis (IPF), COVID-19, and lung cancer. Therefore, as an important serum biomarker in respiratory system diseases, the value of KL-6 still requires further investigation.

Clinical characteristics and outcome of lung cancer in patients with fibrosing interstitial lung disease

BACKGROUND

Lung cancer (LC) is an important comorbidity of interstitial lung disease (ILD) and has a poor prognosis. The clinical characteristics and outcome of each ILD subtype in LC patients have not been sufficiently investigated. Therefore, this study aimed to evaluate the difference between idiopathic pulmonary fibrosis (IPF) and non-IPF ILD as well as prognostic factors in patients with ILD-LC.

METHODS

The medical records of 163 patients diagnosed with ILD-LC at Asan Medical Center from January 2018 to May 2023 were retrospectively reviewed. Baseline characteristics and clinical outcomes were compared between the IPF-LC and non-IPF ILD-LC groups, and prognostic factors were analyzed using the Cox proportional-hazard model.

RESULTS

The median follow-up period was 11 months after the cancer diagnosis. No statistically significant differences were observed in clinical characteristics and mortality rates (median survival: 26 vs. 20 months, p = 0.530) between the groups. The independent prognostic factors in patients with ILD-LC were higher level of Krebs von den Lungen-6 (≥ 1000 U/mL, hazard ratio [HR] 1.970, 95% confidence interval [CI] 1.026-3.783, p = 0.025) and advanced clinical stage of LC (compared with stage I, HR 3.876 for stage II, p = 0.025, HR 5.092 for stage III, p = 0.002, and HR 5.626 for stage IV, p = 0.002). In terms of treatment, surgery was the significant factor for survival (HR 0.235; 95% CI 0.106-0.520; p < 0.001).

CONCLUSIONS

No survival difference was observed between IPF-LC and non-IPF ILD-LC patients. A higher level of Krebs von den Lungen-6 may act as a prognostic marker in ILD-LC patients.

Prognostic value of blood-based protein biomarkers in non-small cell lung cancer: A critical review and 2008-2022 update

BACKGROUND

Therapeutic possibilities for non-small cell lung cancer (NSCLC) have considerably increased during recent decades.

OBJECTIVE

To summarize the prognostic relevance of serum tumor markers (STM) for early and late-stage NSCLC patients treated with classical chemotherapies, novel targeted and immune therapies.

METHODS

A PubMed database search was conducted for prognostic studies on carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA 21-1), neuron-specific enolase, squamous-cell carcinoma antigen, progastrin-releasing-peptide, CA125, CA 19-9 and CA 15-3 STMs in NSCLC patients published from 2008 until June 2022.

RESULTS

Out of 1069 studies, 141 were identified as meeting the inclusion criteria. A considerable heterogeneity regarding design, patient number, analytical and statistical methods was observed. High pretherapeutic CYFRA 21-1 levels and insufficient decreases indicated unfavorable prognosis in many studies on NSCLC patients treated with chemo-, targeted and immunotherapies or their combinations in early and advanced stages. Similar results were seen for CEA in chemotherapy, however, high pretherapeutic levels were sometimes favorable in targeted therapies. CA125 is a promising prognostic marker in patients treated with immunotherapies. Combinations of STMs further increased the prognostic value over single markers.

CONCLUSION

Protein STMs, especially CYFRA 21-1, have prognostic potential in early and advanced stage NSCLC. For future STM investigations, better adherence to comparable study designs, analytical methods, outcome measures and statistical evaluation standards is recommended.

Clinical significance of KL-6 in immune-checkpoint inhibitor treatment for non-small cell lung cancer

PURPOSE

Krebs von den Lungen-6 (KL-6) functions as a tumor marker, as well as a diagnostic tool for interstitial pneumonia (IP). However, the significance of KL-6 in the immune-checkpoint inhibitor (ICI) treatment of non-small cell lung cancer (NSCLC), especially in patients without IP, is unknown.

METHODS

This multicenter, retrospective study, which included patients with advanced NSCLC who received ICI therapy, analyzed the association between serum KL-6 values and ICI efficacy and the association between serum KL-6 values and ICI-induced interstitial lung disease (ILD) occurrence, focusing primarily on patients without IP.

RESULTS

In total, 322 patients had available KL-6 values before ICI therapy. Among 202 patients without IP who received ICI monotherapy, the high-KL-6 group (≥ 500 U/mL) showed significantly shorter progression-free survival (PFS) and overall survival (OS) than the low-KL-6 group (< 500 U/mL) (median: 2.1 vs. 3.6 months, p = 0.048; median: 9.2 vs. 14.5 months, p = 0.035). There was no significant difference in response rate between the KL-6 high and low groups (19% vs. 29%, p = 0.14). In the multivariate analysis, high KL-6 was a significant predictor of poor PFS (hazard ratio [HR], 1.52; 95% confidence interval [CI] 1.10-2.11, p = 0.012) and OS (HR, 1.51; 95% CI 1.07 - 2.13, p = 0.019) for patients treated with ICI monotherapy. There was no significant difference in the occurrence rate of ILD between the high KL-6 and low KL-6 groups in patients with (20% vs. 15%, p = 1.00) or without IP (12% vs. 12%, p = 1.00).

CONCLUSION

In ICI monotherapy for NSCLC without IP, elevated serum KL-6 levels were associated with poorer outcomes.

Establishment and validation of nomogram for predicting immuno checkpoint inhibitor related pneumonia

Objective

Cancer is one of the main causes of death worldwide. Although immunotherapy brings hope for cancer treatment, it is also accompanied by immune checkpoint inhibitor-related adverse events (irAEs). Immune checkpoint inhibitor pneumonia (CIP) is a potentially fatal adverse event, but there is still a lack of effective markers and prediction models to identify patients at increased risk of CIP.

Methods

A total of 369 cancer patients treated between 2017 and 2022 with immune checkpoint inhibitors at Shengjing Hospital of China Medical University and Liaoning People's Hospital were recruited for this study. Independent variables were selected by differences and binary logistic regression analysis, and a risk assessment nomogram was constructed for CIP risk. The accuracy and discriminative abilities of the nomogram were evaluated by calibration plots, receiver operating characteristic curves (ROCs) and decision curve analyses (DCAs).

Results

Binary logistic regression analysis showed that smoking history, acute phase proteins [interleukin (IL-6) and C-reactive protein (CRP)], CD8 + T lymphocyte count and serum alveolar protein [surface protein-A (SP-A) and Krebs Von den Lungen-6 (KL-6)] were significantly associated with CIP risk. A nomogram consisting of these variables was established and validated by different analyses.

Conclusions

We developed an effective risk nomogram for CIP prediction in immune-checkpoint inhibitor administrated cancer patients, which will further assist early detection of immunotherapy-related adverse events.

Apalutamide-induced severe interstitial lung disease: A report of two cases from Japan

Apalutamide, a competitive inhibitor of the androgen receptor, is being increasingly used for the treatment of prostate cancer. There have been few reports of interstitial lung disease in clinical trials of apalutamide. However, two cases of apalutamide-induced interstitial lung disease with respiratory failure in Japanese males, who were successfully treated with high-dose corticosteroids, are presented here. These cases suggest that clinicians should be alert to the potentially life-threatening risk of pulmonary toxicity associated with apalutamide treatment.

The role of mucin 1 in respiratory diseases

Recent evidence has demonstrated that mucin 1 (MUC1) is involved in many pathological processes that occur in the lung. MUC1 is a transmembrane protein mainly expressed by epithelial and hematopoietic cells. It has a receptor-like structure, which can sense the external environment and activate intracellular signal transduction pathways through its cytoplasmic domain. The extracellular domain of MUC1 can be released to the external environment, thus acting as a decoy barrier to mucosal pathogens, as well as serving as a serum biomarker for the diagnosis and prognosis of several respiratory diseases such as lung cancer and interstitial lung diseases. Furthermore, bioactivated MUC1-cytoplasmic tail (CT) has been shown to act as an anti-inflammatory molecule in several airway infections and mediates the expression of anti-inflammatory genes in lung diseases such as chronic rhinosinusitis, chronic obstructive pulmonary disease and severe asthma. Bioactivated MUC1-CT has also been reported to interact with several effectors linked to cellular transformation, contributing to the progression of respiratory diseases such as lung cancer and pulmonary fibrosis. In this review, we summarise the current knowledge of MUC1 as a promising biomarker and drug target for lung disease.

Novel Perspectives Regarding the Pathology, Inflammation, and Biomarkers of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute inflammation of the lung resulting from damage to the alveolar-capillary membrane, and it is diagnosed using a combination of clinical and physiological variables. ARDS develops in approximately 10% of hospitalised patients with pneumonia and has a mortality rate of approximately 40%. Recent research has identified several biomarkers associated with ARDS pathophysiology, and these may be useful for diagnosing and monitoring ARDS. They may also highlight potential therapeutic targets. This review summarises our current understanding of those clinical biomarkers: (1) biomarkers of alveolar and bronchiolar injury, (2) biomarkers of endothelial damage and coagulation, and (3) biomarkers for treatment responses.

Markers Useful in Monitoring Radiation-Induced Lung Injury in Lung Cancer Patients: A Review

In 2018, lung cancer was the most common cancer and the most common cause of cancer death, accounting for a 1.76 million deaths. Radiotherapy (RT) is a widely used and effective non-surgical cancer treatment that induces remission in, and even cures, patients with lung cancer. However, RT faces some restrictions linked to the radioresistance and treatment toxicity, manifesting in radiation-induced lung injury (RILI). About 30–40% of lung cancer patients will develop RILI, which next to the local recurrence and distant metastasis is a substantial challenge to the successful management of lung cancer treatment. These data indicate an urgent need of looking for novel, precise biomarkers of individual response and risk of side effects in the course of RT. The aim of this review was to summarize both preclinical and clinical approaches in RILI monitoring that could be brought into clinical practice. Next to transforming growth factor-β1 (TGFβ1) that was reported as one of the most important growth factors expressed in the tissues after ionizing radiation (IR), there is a group of novel, potential biomarkers—microRNAs—that may be used as predictive biomarkers in therapy response and disease prognosis.

Prognostic and Clinicopathological Significance of MUC Family Members in Colorectal Cancer: A Systematic Review and Meta-Analysis

Objective

To assess the association between MUC expression levels in colorectal cancer (CRC) tissues and prognosis and investigate the associations between MUC expression levels and CRC clinicopathological characteristics.

Methods

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception through September 13, 2019, to identify studies investigating the association between MUC expression levels in CRC tissues and prognosis. Pooled hazard ratios (HRs) or odds ratio (ORs) with 95% confidence intervals (CIs) were used to evaluate associations between MUC expression levels and prognosis or clinicopathological characteristics, respectively. The heterogeneity between studies was assessed by the I² values, whereas the likelihood of publication bias was assessed by Egger's linear regression and Begg's rank correlation test.

Results

Among 33 included studies (n = 6032 patients), there were no associations between combined MUC phenotype expression levels and overall survival (OS) or disease-free survival (DFS)/relapse-free survival (RFS) in patients with CRC. In subgroup analyses, the upregulated MUC1 expression (HR = 1.50; 95% CI, 1.29–1.74; P < 0.00001) was associated with poor OS. However, the upregulated MUC2 expression (HR = 0.64; 95% CI, 0.52–0.79; P < 0.00001) was associated with better OS. Furthermore, a high level of MUC1 expression (HR = 1.99; 95% CI, 0.99–3.99; P = 0.05) was associated with shorter DFS/RFS. However, patients with a low level of MUC2 tumors showed better DFS/RFS than patients with a high level of MUC2 tumors (HR = 0.71; 95% CI, 0.49–1.04; P = 0.08; P = 0.0.009, I² = 67%) and MUC5AC expression (HR = 0.56; 95% CI, 0.38–0.82; P = 0.003) was associated with longer DFS/RFS. In addition, a high level of MUC1 expression was associated with CRC in the rectum, deeper invasion, lymph node metastasis, distant metastasis, advanced tumor stage, and lymphatic invasion. A high level of MUC2 expression had a protective effect. High secretion of MUC5AC is associated with colon cancer compared with rectal cancer.

Conclusion

The protein expression of MUC1 might be a poor biomarker in colorectal cancer and might play a role in tumor transformation and metastasis. However, the protein expression of MUC2 expression might have a protective effect. Furthermore, randomized controlled trials (RCTs) of large patients are needed to confirm the results.

Whole genome sequencing to identify predictive markers for the risk of drug-induced interstitial lung disease

Drug-induced interstitial lung disease (DIILD) is a serious side effect of chemotherapy in cancer patients with an extremely high mortality rate. In this study, to identify genetic variants with greater risk of DIILD, we carried out whole genome sequencing (WGS) of germline DNA samples from 26 patients who developed DIILD, and conducted a case-control association study between these 26 cases and general Japanese population controls registered in the integrative Japanese Genome Variation Database (iJGVD) as a screening study. The associations of 42 single nucleotide variants (SNVs) showing P < 0.0001 were further validated using an independent cohort of 18 DIILD cases as a replication study. A further combined analysis of the screening and replication studies showed a possible association of two SNVs, rs35198919 in intron 1 of the chromosome 22 open reading frame 34 (C22orf34) and rs12625311 in intron 1 of the teashirt zinc finger homeobox 2 (TSHZ2), with DIILD (P_combined = 1.87 × 10⁻⁵ and 5.16 × 10⁻⁵, respectively). Furthermore, in a subgroup analysis of epidermal growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI)-induced interstitial lung disease (ILD), we observed seven candidate SNVs that were possibly associated with ILD (P < 0.00001). This is the first study to identify genetic markers for the risk of DIILD using WGS. Collectively, our novel findings indicate that these SNVs may be applicable for predicting the risk of DIILD in patients receiving chemotherapy.

Analytical and Clinical Performance of the Nanopia Krebs von den Lungen 6 Assay in Korean Patients With Interstitial Lung Diseases

BACKGROUND

Krebs von den Lungen 6 (KL-6) is a sensitive marker for diagnosing, monitoring, and predicting the prognoses of interstitial lung diseases (ILDs). This study aimed to evaluate the performance of the Nanopia KL-6 assay (Sekisui Medical, Tokyo, Japan) and to test the relationship between KL-6 concentrations and clinical results.

METHODS

In total, 230 patients diagnosed as having ILDs were enrolled. All underwent high-resolution computed tomography (HRCT) followed by the pulmonary function test (PFT). We also enrolled 116 disease controls and 200 healthy controls. Evaluation of the Nanopia KL-6 assay involved determination of precision, linearity, and limit of quantification (LOQ). Results from the Nanopia KL-6 assay were compared with those from ELISA and correlated with the HRCT and PFT results.

RESULTS

The within-laboratory precisions were <2% of CV, and linearity was acceptable between 52.2 and 4,966.5 U/mL. The LOQ was 45.2 U/mL. Nanopia and ELISA results were strongly correlated (r=0.979). The average concentration of KL-6 was greater in ILD patients (711.5 U/mL) than in the disease (168.4 U/mL) and healthy (209.4 U/mL) controls. Serum KL-6 concentrations were strongly and moderately correlated with the extent of lung involvement and presence of typical HRCT abnormalities, respectively, and moderately correlated with PFT parameters.

CONCLUSIONS

The overall analytical and clinical performance of the Nanopia KL-6 assay was acceptable. Our study is the first to compare assay platforms and show correlations between KL-6 concentrations and HRCT or PFT results in Korean ILD patients.

Quantitative proteomics analysis identifies MUC1 as an effect sensor of EGFR inhibition

Tumor responses to cancer therapeutics are generally monitored every 2-3 months based on changes in tumor size. Dynamic biomarkers that reflect effective engagement of targeted therapeutics to the targeted pathway, so-called "effect sensors", would fulfill a need for non-invasive, drug-specific indicators of early treatment effect. Using a proteomics approach to identify effect sensors, we demonstrated MUC1 upregulation in response to epidermal growth factor receptor (EGFR)-targeting treatments in breast and lung cancer models. To achieve this, using semi-quantitative mass spectrometry, we found MUC1 to be significantly and durably upregulated in response to erlotinib, an EGFR-targeting treatment. MUC1 upregulation was regulated transcriptionally, involving PI3K-signaling and STAT3. We validated these results in erlotinib-sensitive human breast and non-small lung cancer cell lines. Importantly, erlotinib treatment of mice bearing SUM149 xenografts resulted in increased MUC1 shedding into plasma. Analysis of MUC1 using serial blood sampling may therefore be a new, relatively non-invasive tool to monitor early and drug-specific effects of EGFR-targeting therapeutics.

The extent of ground-glass attenuation is a risk factor of chemotherapy-related exacerbation of interstitial lung disease in patients with non-small cell lung cancer

OBJECTIVES

Chemotherapy-related acute exacerbation (AE) of interstitial lung disease (ILD) is observed in certain patients with non-small cell lung cancer (NSCLC) who have ILD. Although the prognosis of AE-ILD is extremely poor, there are no established risk factors for its occurrence. Therefore, we retrospectively investigated whether high-resolution computed tomography (HRCT) findings could identify risk factors for AE-ILD.

MATERIALS AND METHODS

Between January 2005 and December 2016, 35 patients with NSCLC who received chemotherapy at Hiroshima University Hospital and were diagnosed with ILD on HRCT were enrolled. The extent of ground-glass attenuation (GGA), reticulation, honeycomb appearance, and emphysema, as well as the presence of micronodules, traction bronchiectasis, and consolidation were evaluated in five levels of the lung bilaterally. The HRCT scores of GGA, reticulation, honeycomb appearance, and emphysema were determined by the following formula: 100 × sum of the extent of the HRCT findings/lung area.

RESULTS

Thirty-five patients underwent various first- to fifth-line chemotherapy regimens. Nine patients (25.7%) developed AE-ILD. The median HRCT scores of GGA and reticulation were significantly higher in patients with AE-ILD than in those without. On univariate analysis, a GGA area score ≥ 24.8, reticulation area score ≥ 19.5, and KL-6 level ≥ 946 U/mL were significant risk factors. Multivariate logistic analysis revealed that only a GGA area score ≥ 24.8 was an independent risk factor of AE-ILD.

CONCLUSIONS

The GGA area on HRCT is a risk factor for chemotherapy-related AE-ILD. Therefore, this parameter can be used to predict the risk of AE-ILD before administering chemotherapy.

MUC1 overexpression predicts worse survival in patients with non-small cell lung cancer: evidence from an updated meta-analysis

Background

Previous studies on the prognostic role of MUC1 expression in non-small cell lung cancer (NSCLC) remain controversial. We conducted a meta-analysis to appraise the clinicopathological and prognostic effect of MUC1 in NSCLC patients.

Materials and Methods

Searches of PubMed, EMBASE and CNKI (Chinese National Knowledge Infrastructure) were conducted and relevant studies were extracted. The pooled hazard ratio (HR) or odds ratio (OR) with 95% confidence intervals (CIs) were used to estimate effects. Heterogeneity among studies and publication bias were also evaluated.

Results

A total of 15 studies with 1,682 patients were included in this meta-analysis. The pooled HRs indicated that elevated MUC1 expression was associated with poorer overall survival (HR = 2.12, 95% CI: 1.47–3.05; P < 0.001) and progression-free survival (HR = 2.00, 95% CI: 1.53-2.62; P < 0.001) in patients with NSCLC. Significant associations were also found in patients treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) (HR = 3.16, 95% CI: 2.21–4.52, P < 0.001) and with a platinum-based regimen (HR = 4.35, 95% CI: 2.45–7.72, P < 0.001). Additionally, MUC1 overexpression was significantly associated with performance status (OR = 2.32, 95% CI: 1.13–4.73, P = 0.021).

Conclusions

MUC1 could be a valuable biomarker of the prognoses of NSCLC patients.

Enteroaggregative Escherichia coli Adherence Fimbriae Drive Inflammatory Cell Recruitment via Interactions with Epithelial MUC1

Enteroaggregative Escherichia coli (EAEC) causes diarrhea and intestinal inflammation worldwide. EAEC strains are characterized by the presence of aggregative adherence fimbriae (AAF), which play a key role in pathogenesis by mediating attachment to the intestinal mucosa and by triggering host inflammatory responses. Here, we identify the epithelial transmembrane mucin MUC1 as an intestinal host cell receptor for EAEC, demonstrating that AAF-mediated interactions between EAEC and MUC1 facilitate enhanced bacterial adhesion. We further demonstrate that EAEC infection also causes elevated expression of MUC1 in inflamed human intestinal tissues. Moreover, we find that MUC1 facilitates AAF-dependent migration of neutrophils across the epithelium in response to EAEC infection. Thus, we show for the first time a proinflammatory role for MUC1 in the host response to an intestinal pathogen.

EAEC is a clinically important intestinal pathogen that triggers intestinal inflammation and diarrheal illness via mechanisms that are not yet fully understood. Our findings provide new insight into how EAEC triggers host inflammation and underscores the pivotal role of AAFs—the principal adhesins of EAEC—in driving EAEC-associated disease. Most importantly, our findings add a new dimension to the signaling properties of the transmembrane mucin MUC1. Mostly studied for its role in various forms of cancer, MUC1 is widely regarded as playing an anti-inflammatory role in response to infection with bacterial pathogens in various tissues. However, the role of MUC1 during intestinal infections has not been previously explored, and our results describe the first report of MUC1 as a proinflammatory factor following intestinal infection.

MUC1 in lung adenocarcinoma: cross-sectional genetic and serological study

Background

Mucin 1 (MUC1) contributes to the growth and metastasis of various cancers, including lung cancer, and MUC1 gene length polymorphisms are associated with susceptibility to lung cancer and its prognosis. In contrast, the association between rs4072037, a single nucleotide polymorphism in MUC1, and lung cancer has not been well studied.

Methods

In the present study, we determined the rs4072037 genotype and measured serum KL-6 levels to evaluate the association between lung adenocarcinoma (ADC) and rs4072037 or serum KL-6 levels. DNA samples were available for 172 patients and these were included in the genomic analyses. In addition, 304 patients were included in the serum analyses. Furthermore, 276 healthy volunteers were included in both genomic and serum analyses.

Results

The rs4072037 genotype was not associated with susceptibility to lung ADC or its prognosis. Interestingly, serum KL-6 levels significantly differed according to rs4072037 genotype in those with T1 or T2 (P < 0.001), N0 or N1 (P = 0.002) and M0 (P < 0.001), but not in those with T3 or T4 (P = 0.882), N2 or N3 (P = 0.616) and M1a or M1b (P = 0.501). Serum KL-6 levels were significantly associated with the presence of lung ADC, as well as with its progression and prognosis, indicating the crucial involvement of KL-6/MUC1 in the development of lung cancer and its progression.

Conclusion

Based on these findings, we conclude that rs4072037 does not have a significant impact on the pathogenesis or prognosis of lung ADC, whereas serum KL-6 levels, which might reflecting the molecular length of MUC1, are significantly associated with lung ADC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3272-y) contains supplementary material, which is available to authorized users.

Blood Biomarkers in Idiopathic Pulmonary Fibrosis

PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease of unknown origin whose incidence has been increasing over the latest decade partly as a consequence of population ageing. New anti-fibrotic therapy including pirfenidone and nintedanib have now proven efficacy in slowing down the disease. Nevertheless, diagnosis and follow-up of IPF remain challenging.

METHODS

This review examines the recent literature on potentially useful blood molecular and cellular biomarkers in IPF. Most of the proposed biomarkers belong to chemokines (IL-8, CCL18), proteases (MMP-1 and MMP-7), and growth factors (IGBPs) families. Circulating T cells and fibrocytes have also gained recent interest in that respect. Up to now, though several interesting candidates are profiling there has not been a single biomarker, which proved to be specific of the disease and predictive of the evolution (decline of pulmonary function test values, risk of acute exacerbation or mortality).

CONCLUSION

Large scale multicentric studies are eagerly needed to confirm the utility of these biomarkers.

Mucin-1 correlates with survival, smoking status, and growth patterns in lung adenocarcinoma

Mucin-1 (MUC1) affects cancer progression in lung adenocarcinoma, and its aberrant expression pattern has been correlated with poor tumor differentiation and impaired prognosis. In this study, the immunohistochemical expression of MUC1 and Mucin-4 (MUC4) was analyzed in a series of 106 surgically operated stage I-IV pulmonary adenocarcinomas. MUC1 immunohistochemistry was evaluated according to the Nagai classification, and the immunohistochemical profile of the tumors was correlated with detailed clinical and histological data. The effect of cigarette smoke on MUC1 expression in lung cancer cell lines was examined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunoelectron microscopy (IEM). In contrast to the normal apical localization of MUC1, a basolateral and cytoplasmic (depolarized) MUC1 expression pattern was frequently encountered in the high-grade subtypes, i.e., solid predominant adenocarcinoma and the cribriform variant of acinar predominant adenocarcinoma (p < 0.001), and was rarely observed in tumors containing a non-predominant lepidic component (p < 0.001). Furthermore, the altered staining pattern of MUC1 correlated with stage (p = 0.002), reduced overall survival (p = 0.031), and was associated with smoking (p < 0.001). When H1650 adenocarcinoma cells were exposed to cigarette smoke and analyzed by RT-qPCR and IEM, the levels of the MUC1 transcript and protein were elevated (p = 0.042). In conclusion, MUC1 participates in the pathogenesis of lung adenocarcinoma and associates with smoking both in vitro and in vivo. In lung adenocarcinoma, depolarized MUC1 protein expression correlated with histological growth patterns, stage, and patient outcome.

Effects of the multiple O-glycosylation states on antibody recognition of the immunodominant motif in MUC1 extracellular tandem repeats

The conformational impact of the clusteredO-glycans strongly influences recognition by antibodies of the cancer-relevant epitope in the MUC1 extracellular tandem repeat domain.

Tecemotide in unresectable stage III non-small-cell lung cancer in the phase III START study: updated overall survival and biomarker analyses

BACKGROUND

Tecemotide is a MUC1-antigen-specific cancer immunotherapy. The phase III START study did not meet its primary end point but reported notable survival benefit with tecemotide versus placebo in an exploratory analysis of the predefined patient subgroup treated with concurrent chemoradiotherapy. Here, we attempted to gain further insight into the effects of tecemotide in START.

PATIENTS AND METHODS

START recruited patients who did not progress following frontline chemoradiotherapy for unresectable stage III non-small-cell lung cancer. We present updated overall survival (OS) data and exploratory analyses of OS for baseline biomarkers: soluble MUC1 (sMUC1), antinuclear antibodies (ANA), neutrophil/lymphocyte ratio (NLR), lymphocyte count, and HLA type.

RESULTS

Updated OS data are consistent with the primary analysis: median 25.8 months (tecemotide) versus 22.4 months (placebo) (HR 0.89, 95% CI 0.77-1.03, P = 0.111), with ∼20 months additional median follow-up time compared with the primary analysis. Exploratory analysis of the predefined subgroup treated with concurrent chemoradiotherapy revealed clinically relevant prolonged OS with tecemotide versus placebo (29.4 versus 20.8 months; HR 0.81, 95% CI 0.68-0.98, P = 0.026). No improvement was seen with sequential chemoradiotherapy. High sMUC1 and ANA correlated with a possible survival benefit with tecemotide (interaction P = 0.0085 and 0.0022) and might have future value as biomarkers. Interactions between lymphocyte count, NLR, or prespecified HLA alleles and treatment effect were not observed.

CONCLUSION

Updated OS data support potential treatment benefit with tecemotide in patients treated with concurrent chemoradiotherapy. Exploratory biomarker analyses suggest that elevated sMUC1 or ANA levels correlate with tecemotide benefit.

CLINICALTRIALSGOV NUMBER

NCT00409188.

Prognostic value of serum cytokeratin 19 fragments (Cyfra 21-1) in patients with non-small cell lung cancer

The role of serum CYFRA 21-1 level in patients with non-small cell lung cancer (NSCLC) remains to be defined. To re-evaluate the impact of serum CYFRA 21-1 in NSCLC survival, we performed this meta-analysis. Databases were searched to identify relevant studies reported after the publication of a meta-analysis in 2004. Totally, 31 studies with 6394 patients were included in this meta-analysis. The pooled Hazard ratios (HRs) indicated that high CYFRA 21-1 level was associated with poor prognosis on overall survival (OS) in patients with NSCLC (HR = 1.60; 95%CI = 1.36–1.89; P < 0.001). The pooled HRs were 2.18 (95%CI = 1.70, 2.80; P = 0.347) for patients at stage I–IIIA and 1.47 (95%CI = 1.02, 2.11; P < 0.001) for stage IIIB–IV. When stratified by surgical intervention, pooled HRs were 1.94 (95%CI = 1.42–2.67; P < 0.001) for studies with surgery and 1.24 (95%CI = 0.79–1.95; P < 0.001) for studies without surgery. Significant associations were also found in the patients treated with EGFR-TKIs (HR = 1.83; 95%CI = 1.31–2.58; P = 0.011) and platinum-based regimen (HR = 1.53; 95%CI = 1.18–1.99; P = 0.001). Meta-analysis of CYFRA 21-1 related to PFS was performed and pooled HR was 1.41 (95%CI = 1.19–1.69; P < 0.001). Our results indicate that high level of serum CYFRA 21-1 is a negative prognostic indicator of patients with NSCLC.

Expressions of MUC1 and vascular endothelial growth factor mRNA in blood are biomarkers for predicting efficacy of gefitinib treatment in non-small cell lung cancer

Background

Gefitinib, an EGFR-tyrosine kinase inhibitor, significantly improve prognosis in patients with advanced non-small cell lung cancer (NSCLC). The aim of this study was to evaluate the usefulness of MUC1 and vascular endothelial growth factor (VEGF) mRNA expression in peripheral blood as means of predicting benefit from gefitinib therapy in NSCLC patients.

Methods

MUC1 and VEGF mRNA expressions were detected in peripheral blood of 66 patients with advanced NSCLC before (B0) and 4 weeks after treatment (B4w) with gefitinib, using real-time quantitative-PCR assay. Correlations between blood MUC1 and VEGF mRNA expression at B0 and B4w and the response to gefitinib treatment and survival were analyzed.

Results

Blood levels of MUC1 and VEGF mRNA at B0 and at B4w were significantly higher in patients with progressive disease than in those with partial response and stable disease. Furthermore, blood MUC1 and VEGF mRNA positivity at two time points were strongly associated with shorter progression-free survival (PFS) and overall survival (OS) (P = 0.005 and P = 0.008 at B0, and P < 0.001 and P = 0.001 at B4w, respectively, for MUC1; P = 0.004 and P = 0.009 at B0, and P = 0.001 and P < 0.001 at B4w, respectively, for VEGF). Multivariate analyses demonstrated that blood MUC1 and VEGF mRNA positivity at B0 and B4w were independent factors for predicting worse PFS and OS.

Conclusions

MUC1 and VEGF mRNA positivity in blood seem to be indicators of unfavorable response and poor PFS and OS in patients with advanced NSCLC treated with gefitinib and may be promising noninvasive and repeatable markers for predicting efficacy of gefitinib treatment.

A straightforward protocol for the preparation of high performance microarray displaying synthetic MUC1 glycopeptides

BACKGROUND

Human serum MUC1 peptide fragments bearing aberrant O-glycans are secreted from columnar epithelial cell surfaces and known as clinically important serum biomarkers for the epithelial carcinoma when a specific monoclonal antibody can probe disease-relevant epitopes. Despite the growing importance of MUC1 glycopeptides as biomarkers, the precise epitopes of most anti-MUC1 monoclonal antibodies remains unclear.

METHODS

A novel protocol for the fabrication of versatile microarray displaying peptide/glycopeptide library was investigated for the construction of highly sensitive and accurate epitope mapping assay of various anti-MUC1 antibodies.

RESULTS

Selective imine-coupling between aminooxy-functionalized methacrylic copolymer with phosphorylcholine unit and synthetic MUC1 glycopeptides-capped by a ketone linker at N-terminus provided a facile and seamless protocol for the preparation of glycopeptides microarray platform. It was demonstrated that anti-KL-6 monoclonal antibody shows an extremely specific and strong binding affinity toward MUC1 fragments carrying sialyl T antigen (Neu5Acα2,3Galβ1,3GalNAcα1→) at Pro-Asp-Thr-Arg motif when compared with other seven anti-MUC1 monoclonal antibodies such as VU-3D1, VU-12E1, VU-11E2, Ma552, VU-3C6, SM3, and DF3. The present microarray also uncovered the occurrence of IgG autoantibodies in healthy human sera that bind specifically with sialyl T antigen attached at five potential O-glycosylation sites of MUC1 tandem repeats.

CONCLUSION

We established a straightforward strategy toward the standardized microarray platform allowing highly sensitive and accurate epitope mapping analysis by reducing the background noise due to nonspecific protein adsorption.

GENERAL SIGNIFICANCE

The present approach would greatly accelerate the discovery research of new class autoantibodies as well as the development of therapeutic mAbs reacting specifically with disease-relevant epitopes.

Site-specific conformational alteration induced by sialylation of MUC1 tandem repeating glycopeptides at an epitope region for the anti-KL-6 monoclonal antibody

Protein O-glycosylation is an essential step for controlling structure and biological functions of glycoproteins involving differentiation, cell adhesion, immune response, inflammation, and tumorigenesis and metastasis. This study provides evidence of site-specific structural alteration induced during multiple sialylation at Ser/Thr residues of the tandem repeats in human MUC1 glycoprotein. Systematic nuclear magnetic resonance (NMR) study revealed that sialylation of the MUC1 tandem repeating glycopeptide, Pro-Pro-Ala-His-Gly-Val-Thr-Ser-Ala-Pro-Asp-Thr-Arg-Pro-Ala-Pro-Gly-Ser-Thr-Ala with core 2-type O-glycans at five potential glycosylation sites, afforded a specific conformational change at one of the most important cancer-relevant epitopes (Pro-Asp-Thr-Arg). This result indicates that disease-relevant epitope structures of human epithelial cell surface mucins can be altered both by the introduction of an inner GalNAc residue and by the distal sialylation in a peptide sequence-dependent manner. These data demonstrate the feasibility of NMR-based structural characterization of glycopeptides synthesized in a chemical and enzymatic manner in examining the conformational impact of the distal glycosylation at multiple O-glycosylation sites of mucin-like domains.

Utility of KL-6/MUC1 in the clinical management of interstitial lung diseases

Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. Because injury and/or regeneration of type II pneumocytes are prominent histological features of ILDs, substances derived from type II pneumocytes have been the focus of research investigating potential biomarkers for ILD. One important biomarker for ILD is the high-molecular-weight glycoprotein, Krebs von den Lungen-6 (KL-6). KL-6 is now classified as a human MUC1 mucin protein, and regenerating type II pneumocytes are the primary cellular source of KL-6/MUC1 in the affected lungs of patients with ILD. KL-6/MUC1 is detectable in the serum of patients with ILD, and extensive investigations performed primarily in Japan have revealed that serum KL-6/MUC1 is elevated in 70-100% of patients with various ILDs, including idiopathic interstitial pneumonias, collagen vascular disease-associated interstitial pneumonia, hypersensitivity pneumonia, radiation pneumonitis, drug-induced ILDs, acute respiratory distress syndrome, pulmonary sarcoidosis, and pulmonary alveolar proteinosis. The results from these various studies have supported the utility of KL-6/MUC1 as a serum biomarker for detecting these various ILDs. Moreover, KL-6/MUC1 serum levels have been demonstrated to be useful for evaluating disease activity and predicting the clinical outcomes of various ILD types. Based on these observations, we believe that KL-6/MUC1 is currently one of the best and most reliable serum biomarkers available for ILD management.

Interferon (alpha, beta and omega) receptor 2 is a prognostic biomarker for lung cancer

OBJECTIVES

It has been reported that the type I interferon receptor subunit, interferon (alpha, beta and omega) receptor 2 (IFNAR2), is overexpressed in several malignancies, primarily adenocarcinomas (ADCs); however, the biological significance of IFNAR2 in human lung cancer has not yet been studied.

METHODS

Immunohistochemical analysis of 113 surgically resected lung specimens was performed, and the results were evaluated in association with clinical variables, including survival. Serum concentrations of IFNAR2 were also determined by an enzyme-linked immunosorbent assay in 157 lung cancer patients and 164 healthy volunteers.

RESULTS

IFNAR2 overexpression was observed in all histological types of lung cancer examined. Furthermore, strong IFNAR2 expression was associated with shorter progression-free survival (PFS) and overall survival (OS) (p < 0.0001 and p = 0.0110, respectively) in non-small cell lung cancer patients. Multivariate analyses confirmed its independent prognostic value for PFS and OS (p < 0.0001 and p = 0.0222, respectively). IFNAR2 serum levels were also significantly higher in lung cancer patients than in healthy volunteers (p < 0.0001).

CONCLUSIONS

IFNAR2 overexpression was observed in various histological types of lung cancer, and appears to be associated with lung cancers that behave aggressively. The results of this study strongly support the potential of IFNAR2 to be a prognostic biomarker for lung cancer.

Change in serum KL-6 level from baseline is useful for predicting life-threatening EGFR-TKIs induced interstitial lung disease

Background

A high incidence of interstitial lung disease (ILD) has been reported in patients with advanced non-small cell lung cancer (NSCLC) treated with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), particularly in Japanese populations. A previous report from our laboratory demonstrated that KL-6 was a useful serum biomarker to assess the severity of drug-induced pneumonitis. Based on these observations, this study was conducted to evaluate the risk factors of EGFR-TKIs induced ILD and the usefulness of monitoring serum KL-6 levels in patients who developed EGFR-TKIs induced ILD in a large multi-institutional setting.

Methods

We retrospectively reviewed clinical records and radiographies of 341 patients with advanced NSCLCs who were treated with EGFR-TKIs, and analyzed risk factors for the development of EGFR-TKIs induced ILD. Changes of circulating levels of KL-6 were also evaluated in the patients who developed EGFR-TKIs induced ILD.

Results

Among the 341 patients included in this study, 20 (5.9%) developed EGFR-TKIs induced ILD, and 9 (2.6%) died from ILD. Univariate analyses revealed that only preexisting pulmonary fibrosis was a significant risk factor for the development of EGFR-TKIs induced ILD (p = 0.003). Absolute levels of circulating KL-6 at neither baseline nor the onset of ILD could discriminate between life-threatening and non-life threatening EGFR-TKIs induced ILDs. However, we found that the ratios of serum KL-6 levels just after the onset of EGFR-TKIs induced ILD to those at baseline could quite precisely distinguish survivors from non-survivors (p = 0.006) as well as acute interstitial pneumonia (AIP) pattern from non-AIP pattern (p = 0.005).

Conclusions

The results of this study strongly support the potential of KL-6 as a diagnostic biomarker for life-threatening EGFR-TKIs induced ILD. Monitoring of KL-6 is also useful to evaluate the progression and severity of EGFR-TKIs induced ILD.

Serum KL-6 level and the development of bronchiolitis obliterans syndrome in lung transplant recipients

KL-6 is a glycoprotein expressed by pulmonary epithelial cells, and its serum level has been used as a marker of disease activity in a variety of respiratory illnesses. Previously, we showed that KL-6 was elevated in lung transplant recipients diagnosed with BOS. In this study, we followed serum KL-6 levels and lung functions prospectively in lung transplant recipients who were within the first five-yr post-transplant and had no evidence of BOS at the time of study entry. Mean peak KL-6 levels were 596.16 ± 309.32 U/mL in the nine recipients who developed BOS compared to 352.41 ± 140.68 in 36 recipients who did not (p = 0.05). Six of the nine patients with BOS had an absolute rise in KL-6 above baseline level >200 U/mL compared to two of the 37 who had the same increase in KL-6 but did not develop BOS. Using the 200 U/mL elevation of KL-6 from baseline as a threshold for a positive test would produce a sensitivity of 67%, specificity of 95%, PPV of 75%, and a NPV of 92%. In addition, mean KL-6 levels of patients during acute rejection were not significantly elevated compared to the prerejection mean KL-6 levels (p = 0.71). We conclude that serum KL-6 is a relatively specific marker of BOS in lung transplant recipients.

Mucins carrying selectin ligands as predictive biomarkers of disseminated intravascular coagulation complication in ARDS

BACKGROUND

ARDS patients present with intrapulmonary and systemic coagulation abnormalities. We previously demonstrated that circulating KL-6/MUC1 could predict complications of disseminated intravascular coagulation (DIC) in ARDS. Recent studies indicate that circulating mucin can induce intravascular coagulation via interactions with selectin. We, therefore, investigated whether circulating mucins carrying selectin ligands are associated with DIC in ARDS.

METHODS

We evaluated newly diagnosed patients with ARDS (n = 46) or bacterial pneumonia (n = 17), and healthy control subjects (n = 60). Using serum collected at diagnosis, circulating levels of KL-6/MUC1, KL-6/MUC1 carrying sialyl Lewis(a) (SLAK), KL-6/MUC1 carrying sialyl Lewis(x) (SLXK), and P-selectin glycoprotein ligand-1 (PSGL-1) were measured.

RESULTS

Serum mucins with selectin ligands were significantly elevated in patients with ARDS compared with healthy control subjects. Significantly elevated levels of SLAK and SLXK were found in patients with ARDS subsequently complicated with DIC, as compared with those without DIC. In contrast, serum PSGL-1 levels were significantly decreased in ARDS patients with DIC. Furthermore, SLAK was discovered to be an independent predictor of DIC complication in ARDS. Using cutoff levels obtained by receiver operating characteristic curves, we found that these mucins can be used to distinguish between patients with ARDS with and without subsequently occurring DIC. Among the analyzed mucins, SLAK has the highest sensitivity and specificity for predicting future DIC development.

CONCLUSIONS

These results suggest that mucins with selectin ligands are novel markers for ARDS with future complications of DIC, and KL-6/MUC1 carrying selectin ligands may be involved in the pathogenesis of DIC in patients with ARDS.

An essential epitope of anti-MUC1 monoclonal antibody KL-6 revealed by focused glycopeptide library

Human serum Krebs von den Lungen-6 (KL-6) antigen, a high-molecular-weight glycoprotein classified as a polymorphic epithelial mucin (MUC1), is a biomarker of diseases such as interstitial pneumonia, lung adenocarcinoma, breast cancer, colorectal adenocarcinoma, and hepatocellular carcinoma. Anti-KL-6 monoclonal antibody (anti-KL-6 MAb) is therefore a potential diagnostic and therapeutic reagent. Although glycosylation at Thr/Ser residues of the tandem-repeating MUC1 peptides appears to determine the disease-associated antigenic structures of KL-6, an essential epitope structure recognized by anti-KL-6 MAb remains unclear. In the present study, a novel compound library of synthetic MUC1 glycopeptides allowed the first rapid and precise evaluation of the specific epitope structure of anti-KL-6 MAb by combined use of a tailored glycopeptides library and common ELISA protocol. We demonstrated that the minimal antigenic structure, an essential epitope, recognized by anti-KL-6 MAb is a heptapeptide sequence Pro-Asp-Thr-Arg-Pro-Ala-Pro (PDTRPAP), in which the Thr residue is modified by Neu5Ac alpha2,3Gal beta1,3GalNAc alpha (2,3-sialyl T antigen, core 1-type O-glycan). Anti-KL-6 MAb did not bind with other tumor-relevant antigens, such as GalNAc alpha (Tn), Neu5Ac alpha2,6GalNAc alpha (STn), and Gal beta1,3GalNAc alpha (T), except for Neu5Ac alpha2,3Gal beta1,3(Neu5Ac alpha2,6)GalNAc alpha (2,3/2,6-disialyl T). However, anti-KL-6 MAb could not differentiate the above minimal antigenic glycopeptide from some core 2-based glycopeptides involving this crucial epitope structure and showed a similar binding affinity toward these compounds, indicating that branching at the O-6 position of GalNAc residue does not influence the interaction of anti-KL-6 MAb with some MUC1 glycoproteins involving an essential epitope. Actually, anti-KL-6 MAb reacts with 2,3/2,6-disialyl T having a 2,3-sialyl T component. This is why anti-KL-6 MAb often reacts with various kinds of tumor-derived MUC1 glycoproteins as well as a clinically important MUC1 glycoprotein biomarker of interstitial pneumonia, namely KL-6, originally discovered as a circulating pulmonary adenocarcinoma-associated antigen. In other words, combined use of anti-KL-6 MAb and some probes that can differentiate the sugars substituted at the O-6 position of the GalNAc residue in MUC1 glycopeptides including the PDTRPAP sequence might be a promising diagnostic protocol for individual disease-specific biomarkers. It was also revealed that glycosylation at neighboring Thr/Ser residues outside the immunodominant PDTRPAP motif strongly influences the interaction between anti-KL-6 MAb and MUC1 glycopeptides involving the identified epitope. Our novel strategy will greatly facilitate the processes for the identification of the tumor-specific and strong epitopes of various known anti-MUC1 MAbs and allow for their practical application in the generation of improved antibody immunotherapeutics, diagnostics, and MUC1-based cancer vaccines.