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.

MUC5B promoter polymorphism in Japanese patients with idiopathic pulmonary fibrosis.

BACKGROUND AND OBJECTIVE: A single nucleotide polymorphism (SNP) rs35705950 in the promoter of Mucin 5B (MUC5B) has been reported to be associated with idiopathic pulmonary fibrosis (IPF) mainly in Caucasian populations. This study was conducted to confirm the association between rs35705950 and IPF in a Japanese population. METHODS: Genomic DNA was extracted from blood samples in 384 Japanese and 137 German subjects, and rs35705950 was detected by commercially available genotyping assay. RESULTS: The genotype distributions of rs35705950 in Japanese patients with IPF, nonspecific interstitial pneumonia (NSIP) and healthy subjects (HS) were significantly different from those in the German counterparts (P < 0.001, P < 0.001 and P = 0.010, respectively). The rs35705950 T allele frequencies in patients with IPF, NSIP and HS were 3.4%, 1.7% and 0.8%, respectively in the Japanese, while they were 33.1%, 27.4% and 4.3%, respectively in the German cohort. The T allele frequencies in patients with IPF were significantly higher than those in HS both in the Japanese (P = 0.031) and German (P < 0.001) cohorts. CONCLUSIONS: The association between rs35705950 and IPF was also present in this Japanese cohort, but was not as strong as the German counterpart. To our knowledge, this is the first study to successfully validate the association between rs35705950 and IPF in a Japanese ethnicity.

Differences in serum SP-D levels between German and Japanese subjects are associated with SFTPD gene polymorphisms.

BACKGROUND: Surfactant protein A (SP-A) and SP-D are clinically established in Japan as serum biomarkers for diagnosing interstitial lung diseases (ILDs). Serum SP-D levels are affected by genetic variants. We conducted the present study to examine whether serum SP-A and/or SP-D levels in healthy subjects (HS) and patients with ILDs differ between populations with different genetic backgrounds. METHODS: German subjects (n = 303; 138 patients with idiopathic interstitial pneumonias [IIPs] and 165 HS) and Japanese subjects (n = 369; 94 patients with IIPs and 275 HS) were enrolled. Serum SP-A and SP-D levels were measured using an enzyme-linked immunosorbent assay, and four single-nucleotide polymorphisms (SNPs) in the SFTPD gene were genotyped using genomic DNA extracted from blood samples. RESULTS: In both the German and Japanese cohorts, serum SP-A and SP-D levels were significantly higher in patients with IIPs than in HS. There were no significant differences in SP-A levels between the German and Japanese cohorts; however, we found that serum SP-D levels were significantly higher in the German cohort, both in patients with IIPs and in HS (p < 0.001 and p = 0.005, respectively). Furthermore, the genotype distributions of the four SNPs in the SFTPD gene (rs721917, rs1998374, rs2243639, and rs3088308) were significantly different between German and Japanese cohorts (p < 0.001, p < 0.001, p = 0.022, and p < 0.001, respectively), and univariate linear regression analyses revealed that the genotypes of rs721917, rs1998374, and rs2243639 significantly correlated with serum SP-D levels (p < 0.001, p < 0.001, and p = 0.011, respectively). Furthermore, multivariate analyses revealed that the genotypes of these three SNPs correlated independently with serum SP-D levels (p < 0.001, p = 0.001, and p = 0.038, respectively), whereas ethnicity did not significantly correlate with serum SP-D levels. CONCLUSIONS: In patients with IIPs and HS, serum SP-D, but not SP-A, levels were significantly higher in the German than in the Japanese cohort, in part, because of the different frequencies of SFTPD gene polymorphisms.

Different MUC1 gene polymorphisms in German and Japanese ethnicities affect serum KL-6 levels.

BACKGROUND: KL-6 is a high-molecular-weight glycoprotein classified as human Mucin-1 (MUC1). KL-6 has been reported to be a sensitive biomarker for interstitial lung diseases (ILDs) in the Japanese population. It is also known that polymorphisms in the MUC1 gene affect serum levels of KL-6. This study was conducted to evaluate serum levels of KL-6 and MUC1 polymorphisms in both German and Japanese populations. METHODS: Serum levels of KL-6 were measured in 267 patients with ILDs (152 German and 115 Japanese) and 186 healthy subjects (HS) (76 German and 110 Japanese). In addition, rs4072037 single nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction. The optimal cutoff values for discriminating patients with ILDs from HS was determined by receiver operating characteristic analysis based on ethnicity and rs4072037 genotypes. RESULTS: The serum KL-6 levels in patients with ILDs were significantly higher compared with HS in both the German and the Japanese cohorts (both p<0.001). The discriminating cutoff value of serum KL-6 in the German cohort was significantly higher than the value in the Japanese cohort. The difference in the serum levels of KL-6 was significantly associated with the rs4072037 genotype distribution. CONCLUSIONS: Even in the German cohort, the serum KL6 levels were significantly higher in patients with ILDs than HS. Because of differences in the genotype distribution of rs4072037, the KL-6 cutoff value for the German cohort that discriminated patients with ILDs from HS was significantly higher than the value in the Japanese cohort.

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.

Krebs von den Lungen-6 (KL-6) is a prognostic biomarker in patients with surgically resected nonsmall cell lung cancer.

By immunizing mice with a lung adenocarcinoma cell line, we previously established a murine IgG1 monoclonal antibody that recognizes a sialylated sugar chain designated Krebs von den Lungen-6 (KL-6). KL-6 is a high-molecular-weight glycoprotein classified as a human MUC1 mucin. The aim of this study was to determine whether KL-6 expression in tumors correlates with circulating KL-6 levels and whether circulating KL-6 has any prognostic value in patients with surgically resected non-small cell lung cancer (NSCLC). Immunohistochemical analysis of KL-6 expression was performed on 103 NSCLC tissues, and its associations with serum KL-6 levels and survival were examined. We also evaluated whether KL-6 expression patterns and/or serum KL-6 levels could predict prognosis in these NSCLC patients. Immunohistochemical analysis of KL-6 in NSCLC tissues showed that a depolarized KL-6 expression pattern was associated with a high level of circulating KL-6 and a poor prognosis in NSCLC patients who underwent curative surgery. Furthermore, a high circulating KL-6 level was associated with both poorer progression-free survival (PFS) and overall survival (OS), and multivariate analyses confirmed its independent prognostic value for both PFS and OS (p = 0.041 and 0.023, respectively). Our data suggest that preoperative serum KL-6 level reflects KL-6 expression patterns in NSCLC tissue, and can serve as a useful prognostic biomarker in NSCLC patients who undergo curative surgery.

Levels of surfactant proteins A and D and KL-6 are elevated in the induced sputum of chronic obstructive pulmonary disease patients: a sequential sputum analysis.

BACKGROUND: Recent clinical studies have suggested that serum surfactant protein (SP) A, SP-D and Krebs von den Lungen-6 (KL-6) are potential biomarkers for interstitial lung diseases. Serum levels of SP-A and SP-D have also been found to be elevated in chronic obstructive pulmonary disease (COPD), but their significance has not been evaluated or compared in induced sputum samples obtained directly from the airways. OBJECTIVE: A sequential sputum analysis was conducted to assess the value of SP-A, SP-D and KL-6 levels in COPD. METHODS: The study material consisted of induced sputum samples from 61 subjects, 28 with COPD and 33 with prolonged cough (cough lasting >3 weeks and normal spirometry). Sputum was collected in 3 fractions (3 periods of 5 min each). Sputum levels of these proteins were measured, and receiver operating characteristic curve analysis was carried out to evaluate the sensitivity, specificity and area under the curve (AUC) for each fraction. RESULTS: The levels of SP-A, SP-D and KL-6 were higher in patients with COPD than in those with prolonged cough in each of the fractions. Sputum levels of these proteins correlated inversely with obstruction and positively with ageing, smoking history, sputum macrophages and eosinophils. Sputum fractionation had a relatively minor effect on the levels and AUC of these proteins. CONCLUSION: Sequential sputum analysis from 3 consecutive fractions indicated a significant difference in the levels of SP-A, SP-D and KL-6 between COPD and prolonged cough. However, sputum fractionation itself had a relatively minor effect on the levels of these proteins.

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.

Krebs von den Lungen-6 (KL-6) is a high molecular weight glycoprotein classified in the category of human MUC1 mucin. KL-6 has been reported to serve as a sensitive marker for interstitial pneumonia; however, recent studies have suggested that it can also be used as a tumor marker as its origin shows. To further elucidate the clinicopathological significance of circulating KL-6 in lung cancer, we monitored the circulating KL-6 levels in advanced nonsmall cell lung cancer (NSCLC) patients and analyzed the association between these levels and the clinical outcome of EGFR-TKI treatment. The pretreatment levels of circulating KL-6 were found to be significantly higher in progressive disease (PD) patients than disease-controlled (partial response (PR) and stable disease (SD)) patients. Multivariate analyses revealed the circulating KL-6 level to be an independent prognostic factor for overall survival as well as progression-free survival. In addition to these observations, we found that changes in circulating KL-6 levels at 2 weeks after the start of EGFR-TKI treatment from the baseline could quite precisely discriminate PD cases from PR or SD patients and the clinical outcome of EGFR-TKI in NSCLC patients. These results indicate that the monitoring of circulating KL-6 levels in NSCLC patients is effective for both selecting patients to be treated with EGFR-TKI and predicting the clinical outcome of EGFR-TKI. In addition, the findings suggest that the circulating KL-6 level could be used as a clinically relevant biomarker in patients with NSCLC, particularly those who are candidates for EGFR-TKI treatment.

Characterization of SEZ6L2 cell-surface protein as a novel prognostic marker for lung cancer.

To identify molecules that might serve as biomarkers or targets for development of novel molecular therapies, we have been screening genes encoding transmembrane/secretory proteins that are up-regulated in lung cancers, using cDNA microarrays coupled with purification of tumor cells by laser microdissection. A gene encoding seizure-related 6 homolog (mouse)-like 2 (SEZ6L2) protein, was chosen as a candidate for such molecule. Semi-quantitative RT-PCR and western-blot analyses documented increased expression of SEZ6L2 in the majority of primary lung cancers and lung-cancer cell lines examined. SEZ6L2 protein was proven to be present on the surface of lung-cancer cells by flow cytometrical analysis using anti-SEZ6L2 antibody. Immunohistochemical staining for tumor tissue microarray consisting of 440 archived lung-cancer specimens detected positive SEZ6L2 staining in 327 (78%) of 420 non-small cell lung cancers (NSCLCs) and 13 (65%) of 20 small-cell lung cancers (SCLCs) examined. Moreover, NSCLC patients whose tumors revealed a higher level of SEZ6L2 expression suffered shorter tumor-specific survival compared to those with no SEZ6L2 expression. These results indicate that SEZ6L2 should be a useful prognostic marker of lung cancers.