A Real-World Study in Advanced Non–Small Cell Lung Cancer with KRAS Mutations

BACKGROUND: KRAS gene mutations are well known as a key driver of advanced non–small cell lung cancer (NSCLC). The impact of KRAS-mutant subtypes on the survival benefit from salvage chemotherapy is controversial. Here, we present a real-world study in patients across China with advanced NSCLC with KRAS mutations using a website-based patient self-report system. METHODS: We identified a total of 75 patients diagnosed with KRAS-mutant (determined by molecular sequencing) advanced NSCLC between 2014/5/9 and 2019/5/30. KRAS mutation subtypes were divided into G12C and non-G12C groups for statistical analysis. The clinicopathological characteristics and treatment survival benefit in all patients with a KRAS mutation were evaluated. Programmed death-ligand 1 (PD-L1) expression data were collected from 30 patients in the same cohort. RESULTS: In this study, 23 patients with stage IIIB NSCLC and 52 patients with stage IV NSCLC were enrolled with 58 men and 17 women; the median age was 60 years (39–84). All patients received regular chemotherapy/radiotherapy/targeted therapy/immune therapy as per the disease condition. Four main KRAS mutation subtypes were detected: G12C (33%), G12V (19%), G12A (12%), and G12D (12%). Three predominant KRAS comutations were detected: TP53-KRAS (31%), EGFR-KRAS (11%), and STK11-KRAS (8%). Compared with the KRAS non-G12C mutation subtype, patients with the KRAS G12C mutation had potentially longer progression-free survival (PFS) after first-line chemotherapy (4.7 vs. 2.5 months, p < 0.05). Pemetrexed-based chemotherapy appeared to be superior to taxanes- and gemcitabine-based chemotherapies in all patients (PFS: 5.0 vs. 1.5 and 2.3 months, respectively, p > 0.05). Cox regression analysis showed that the KRAS G12C mutation and pemetrexed-based first-line chemotherapy were positive influencers for PFS after first-line (hazard ratios = 0.31 and 0.55, respectively, P < 0.05), but not second-line chemotherapies. CONCLUSION: The KRAS G12C mutation could be a predictive biomarker for better survival benefit from first-line chemotherapy in patients with advanced NSCLC and KRAS mutations. The first-line chemotherapy regimen could possibly influence the outcome in patients with KRAS mutations. Larger and prospective clinical trials are warranted to confirm our conclusions.     

Prognostic Value of Tissue Inhibitor of Metalloproteinase-2 Expression in Patients with Non–Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Background and Objectives

Tissue inhibitor of metalloproteinase-2 (TIMP-2) is a small secretory glycoprotein with anti–matrix metalloproteinase activity. Data on the value of TIMP-2 as a prognostic factor in non–small cell lung cancer (NSCLC) are discordant and remain controversial. A systematic review and meta-analysis was performed to explore this issue.

Methods

We identified the relevant literature by searching the PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure, SinoMed, and Wanfang Data databases (search terms: “non-small cell lung cancer” or “NSCLC” or “Lung Carcinoma, Non-Small-Cell”, “Tissue Inhibitor of Metalloproteinase-2” or “TIMP-2”, and “prognosis” or “prognostic” or “survive”) for updates prior to March 1, 2014. The pooled hazard ratio (HR) of overall survival with a 95% confidence interval (95% CI) was used to evaluate the strength of the association between positive TIMP-2 expression and survival in patients with NSCLC.

Results

We included 12 studies in our systematic review; five studies involving 399 patients with NSCLC were meta-analyzed. The pooled HR of all included patients was 0.57 (95% CI: 0.43–0.77), and the HRs of subgroup analysis according to stage (I–IV), testing method (immunohistochemistry) and high TIMP-2 expression percentage (<50%) were 0.63 (95% CI: 0.43–0.92), 0.55 (95% CI: 0.41–0.74), and 0.50 (95% CI: 0.28–0.88), respectively. These data suggested that high TIMP-2 expression is associated with favorable prognosis in NSCLC. The meta-analysis did not reveal heterogeneity or publication bias.

Conclusions

TIMP-2 expression indicates favorable prognosis in patients with NSCLC; as a protective factor, it could help predict outcome and may guide clinical therapy in the future.     

PD-L1 Expression and Survival among Patients with Advanced Non–Small Cell Lung Cancer Treated with Chemotherapy

BACKGROUND: Recent clinical trial results have suggested that programmed cell death ligand 1 (PD-L1) expression measured by immunohistochemistry may predict response to anti–programmed cell death 1 (PD-1) therapy. Results on the association between PD-L1 expression and survival among patients with advanced non–small cell lung cancer (NSCLC) treated with chemotherapy are inconsistent. MATERIAL AND METHODS: We evaluated the relationship between PD-L1 expression and overall survival (OS) among 204 patients with advanced NSCLC treated at Aarhus University Hospital, Aarhus, Denmark, from 2007 to 2012. PD-L1 expression was measured using a prototype immunohistochemistry assay with the anti–PD-L1 22C3 antibody (Merck). PD-L1 strong positivity and weak positivity were defined to be traceable to the clinical trial version of the assay. RESULTS: Twenty-five percent of patients had PD-L1 strong-positive tumors, and 50% had PD-L1 weak-positive tumors. No statistically significant association was found between PD-L1 expression and survival; adjusted hazard ratio of 1.34 (95% confidence interval, 0.88-2.03; median OS, 9.0 months) for the PD-L1 strong-positive group and 1.07 (0.74-1.55; median OS, 9.8 months) for the PD-L1 weak-positive group compared with the PD-L1–negative group (median OS, 7.5 months). No association was seen between PD-L1 expression and OS when PD-L1 expression levels were stratified by median or tertiles. CONCLUSIONS: In concordance with previous studies, we found PD-L1 measured by immunohistochemistry to be frequently expressed in patients with advanced NSCLC. However, PD-L1 expression is not a strong prognostic marker in patients with advanced NSCLC treated with chemotherapy.     

Short-Term Responders of Non–Small Cell Lung Cancer Patients to EGFR Tyrosine Kinase Inhibitors Display High Prevalence of TP53 Mutations and Primary Resistance Mechanisms

Non–small cell lung cancer (NSCLC) with activating EGFR mutations in exon 19 and 21 typically responds to EGFR tyrosine kinase inhibitors (TKI); however, for some patients, responses last only a few months. The underlying mechanisms of such short responses have not been fully elucidated. Here, we sequenced the genomes of 16 short-term responders (SR) that had progression-free survival (PFS) of less than 6 months on the first-generation EGFR TKI and compared them to 12 long-term responders (LR) that had more than 24 months of PFS. All patients were diagnosed with advanced lung adenocarcinoma and harbored EGFR 19del or L858R mutations before treatment. Paired tumor samples collected before treatment and after relapse (or at the last follow-up) were subjected to targeted next-generation sequencing of 416 cancer-related genes. SR patients were significantly younger than LR patients (P < .001). Collectively, 88% of SR patients had TP53 variations compared to 13% of LR patients (P < .001). Additionally, 37.5% of SR patients carried EGFR amplifications compared to 8% of LR patients. Other potential primary resistance factors were also identified in the pretreatment samples of 12 SR patients (75%), including PTEN loss; BIM deletion polymorphism; and amplifications of EGFR, ERBB2, MET, HRAS, and AKT2. Comparatively, only three LR patients (25%) were detected with EGFR or AKT1 amplifications that could possibly exert resistance. The diverse preexisting resistance mechanisms in SR patients revealed the complexity of defining treatment strategies even for EGFR-sensitive mutations.     

Molecular Characteristics and Clinical Outcomes of EGFR Exon 19 C-Helix Deletion in Non–Small Cell Lung Cancer and Response to EGFR TKIs

Epidermal growth factor receptor (EGFR) exon 19 deletion (E19del) is the most common activating mutation in advanced non–small cell lung cancer (NSCLC) and associates with the sensitivity of EGFR tyrosine kinase inhibitors (TKIs) treatment. However, not all mutant patterns of E19del have been well studied for the limited coverage of regular EGFR mutation testing. Here, we performed a retrospective cohort study of the C-helix E19del in advanced NSCLC patients based on the screening data by the next-generation sequencing (NGS) platform. From May 2012 to December 2019, clinical information and specimen from 7544 consecutive advanced (IIIB/IV) NSCLC patients were collected and screened for EGFR gene mutations by NGS from multicenters in China. The molecular characteristics and responsiveness to first-line EGFR TKIs therapy in NSCLC patients with C-helix E19del were analyzed. The clinical characteristics were also compared between patients with classical E19del and C-helix E19del. Thirty-eight (2.6%) patients with C-helix E19del and 1400 (97.4%) patients with classical E19dels were identified from 1438 patients with E19del. No significant difference in clinical characteristics was observed between the C-helix E19del and classical E19del groups (P > .05), except for histology (P < .001). All 22 patients with C-helix E19del as p.S752_I759del, p.A750_E758del, p.A750_E758delinsP, p.T751_A755delinsNY, p.T751_I759delinsG, p.T751_I759delinsLD, p.T751_I759delinsN, p.T751_L760delinsNL, and p.T751_D761delinsLY reached the best response as partial response rate (72.7%), and the progression-free survival (PFS) was 12.0 months. The PFS after EGFR TKIs in patients with C-helix E19del tended to be longer than patients with classical E19del but has no statistical significance (12.0 months vs 8.5 months, P = .06). The C-helix E19del could be a positive biomarker for predicting response to EGFR TKIs in advanced NSCLC patients. NGS should be the appropriate platform to identify this rare population, especially when patients harbor no actionable driver mutation initially and are reluctant to accept chemotherapy as first-line therapy.     

The Pulmonary Fibrosis Associated MUC5B Promoter Polymorphism Is Prognostic of the Overall Survival in Patients with Non–Small Cell Lung Cancer (NSCLC) Receiving Definitive Radiotherapy

BACKGROUND: MUC5B is glycoprotein secreted by bronchial glands. A promoter variant in MUC5B, rs35705950, was previously found to be strongly associated with the incidence of idiopathic pulmonary fibrosis (IPF) and also the overall survival (OS) of such patients. Patients with IPF and patients with radiation pneumonitis (RP) have the similar pathologic process and clinical symptoms. However, the role of rs35705950 in patients receiving thoracic radiotherapy remains unclear. PATIENTS AND METHODS: In total, 664 patients with NSCLC receiving definitive radiotherapy (total dose ≥60 Gy) were included in our study. RP was scored via the Common Terminology Criteria for Adverse Events v3.0. OS was the second end point. MUC5B rs35705950 was genotyped, and Kaplan-Meier and Cox regression analyses were used to evaluate associations between MUC5B rs35705950 and the risk of RP or OS. RESULTS: The median patient age was 66 years (range 35-88); most (488 [73.2%]) had stage III of the disease. Until the last follow-up, 250 patients developed grade ≥ 2 RP, 82 patients developed grade ≥ 3 RP, and 440 patients died. The median mean lung dose was 17.9 Gy (range 0.15-32.74). No statistically significant associations were observed between genotypes of MUC5B rs35705950 and the incidence of RP ≥ grade 2 either in univariate analysis (hazard ratio [HR] 1.009, 95% confidence interval [CI] 0.728-1.399, P = .958) or in multivariate analysis (HR 0.921, 95% CI 0.645-1.315, P = .65). Similar results were also observed for RP ≥ grade 3, while TT/GT genotypes in MUC5B were significantly associated with poor OS in both univariate analysis (HR 1.287, 95% CI 1.009-1.640, P = .042) and multivariate analysis (HR 1.561, 95% CI 1.193-2.042, P = .001). CONCLUSION: MUC5B promoter polymorphism could be prognostic of the OS among NSCLC patients receiving definitive radiotherapy, although no significant associations were found with the risk of RP.     

Tumstatin,a Matrikine Derived from Collagen Type IVα3, is Elevated in Serum from Patients with Non–Small Cell Lung Cancer

OBJECTIVES: Fibrosis and cancer are characterized by extracellular matrix (ECM) remodeling. The basement membrane is mainly composed by collagen type IV and laminin. Tumstatin is a matrix metalloproteinase-9 (MMP-9) generated matrikine of collagen type IV α3 chain. We evaluated the potential of tumstatin as a diagnostic biomarker of lung disorders. METHODS: A monoclonal antibody was raised against the neo-epitope tumstatin. A novel competitive enzyme-linked immunosorbent assay for detection of tumstatin (TUM), was developed and technically characterized. Levels of TUM were measured in serum of patients with idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), and non–small cell lung cancer (NSCLC) belonging to two cohorts. RESULTS: The developed TUM enzyme-linked immunosorbent assay (ELISA) was technically robust. In cohort 1, levels of TUM were significantly higher in NSCLC compared to healthy controls, IPF, and COPD (P = 0.007, P = 0.03 and P = 0.001, respectively). The area under the receiver operating characteristics (AUROC) for separation of patients with NSCLC from healthy controls was 0.97, for separation of NSCLC and IPF patients was 0.98, and for separation of NSCLC and COPD patients was 1.0. In cohort 2, levels of TUM were also significantly higher in patients with NSCLC compared to healthy controls (P = 0.002), and the AUROC for separation of NSCLC and healthy controls was 0.73. CONCLUSIONS: We developed a technically robust competitive ELISA targeting the fragment tumstatin. The level of TUM in circulation was significantly higher in patients with NSCLC compared to patients with IPF, COPD and healthy controls. The assay provided high diagnostic accuracy in separating NSCLC patients from other lung disorders and from healthy controls.     

Percutaneous Fine-Needle 5% Ethanol-Cisplatin Intratumoral Injection Combined with Second-Line Chemotherapy Improves On the Standard of Care in Patients with Platinum-Pretreated Stage IV Non–Small Cell Lung Cancer

BACKGROUND: Efficacy of second-line chemotherapy in platinum-pretreated non–small cell lung cancer (NSCLC) is poor. This study investigated efficacy of computed tomography–guided percutaneous fine-needle 5% ethanol-cisplatin intratumoral injection (CT-PFNECII) combined with second-line chemotherapy in patients with platinum-pretreated stage IV NSCLC. PATIENTS: Between October 2011 and July 2013, 34 eligible patients were randomly assigned to receive either CT-PFNECII combined with second-line chemotherapy (combination group, n = 17) or second-line chemotherapy alone (chemotherapy group, n = 17). The primary end points were the proportions of patients who achieved an overall response rate (ORR) and disease control rate (DCR). Secondary end points were median survival and progression-free survival (PFS). RESULTS: The ORR and DCR in the combination group were significantly higher than in the chemotherapy group (23.53% vs 11.76% for ORR, P < .01; and 58.82% vs 35.29% for DCR, P < .01). Compared with patients in the chemotherapy group, patients in the combination group had significantly longer PFS (5.4 months vs 3.0 months, P < .01) and median survival (9.5 months vs 5.3 months, P < .01). CONCLUSIONS: CT-PFNECII combined with second-line chemotherapy provided a higher response rate and improved survival than second-line chemotherapy for patients with platinum-pretreated stage IV NSCLC.     

Prediction of Radiation Esophagitis in Non–Small Cell Lung Cancer Using Clinical Factors,Dosimetric Parameters,and Pretreatment Cytokine Levels

Radiation esophagitis (RE) is a common adverse event associated with radiotherapy for non–small cell lung cancer (NSCLC). While plasma cytokine levels have been correlated with other forms of radiation-induced toxicity, their association with RE has been less well studied. We analyzed data from 126 patients treated on 4 prospective clinical trials. Logistic regression models based on combinations of dosimetric factors [maximum dose to 2 cubic cm (D2cc) and generalized equivalent uniform dose (gEUD)], clinical variables, and pretreatment plasma levels of 30 cytokines were developed. Cross-validated estimates of area under the receiver operating characteristic curve (AUC) and log likelihood were used to assess prediction accuracy. Dose-only models predicted grade 3 RE with AUC values of 0.750 (D2cc) and 0.727 (gEUD). Combining clinical factors with D2cc increased the AUC to 0.779. Incorporating pretreatment cytokine measurements, modeled as direct associations with RE and as potential interactions with the dose-esophagitis association, produced AUC values of 0.758 and 0.773, respectively. D2cc and gEUD correlated with grade 3 RE with odds ratios (ORs) of 1.094/Gy and 1.096/Gy, respectively. Female gender was associated with a higher risk of RE, with ORs of 1.09 and 1.112 in the D2cc and gEUD models, respectively. Older age was associated with decreased risk of RE, with ORs of 0.992/year and 0.991/year in the D2cc and gEUD models, respectively. Combining clinical with dosimetric factors but not pretreatment cytokine levels yielded improved prediction of grade 3 RE compared to prediction by dose alone. Such multifactorial modeling may prove useful in directing radiation treatment planning.     

Mutations of the Microsomal Triglyceride-Transfer–Protein Gene in Abetalipoproteinemia

Elevated plasma levels of apolipoprotein B (apoB)–containing lipoproteins constitute a major risk factor for the development of coronary heart disease. In the rare recessively inherited disorder abetalipoproteinemia (ABL) the production of apoB-containing lipoproteins is abolished, despite no abnormality of the apoB gene. In the current study we have characterized the gene encoding a microsomal triglyceride-transfer protein (MTP), localized to chromosome 4q22-24, and have identified a mutation of the MTP gene in both alleles of all individuals in a cohort of eight patients with classical ABL. Each mutant allele is predicted to encode a truncated form of MTP with a variable number of aberrant amino acids at its C-terminal end. Expression of genetically engineered forms of MTP in Cos-1 cells indicates that the C-terminal portion of MTP is necessary for triglyceride-transfer activity. Deletion of 20 amino acids from the carboxyl terminus of the 894-amino-acid protein and a missense mutation of cysteine 878 to serine both abolished activity. These results establish that defects of the MTP gene are the predominant, if not sole, cause of hereditary ABL and that an intact carboxyl terminus is necessary for activity.     

Identification of Five Driver Gene Mutations in Patients with Treatment-Na?ve Lung Adenocarcinoma in Taiwan

Background

It is important to select appropriate targeted therapies for subgroups of patients with lung adenocarcinoma who have specific gene alterations.

Methods

This prospective study was a multicenter project conducted in Taiwan for assessment of lung adenocarcinoma genetic tests. Five oncogenic drivers, including EGFR, KRAS, BRAF, HER2 and EML4-ALK fusion mutations, were tested. EGFR, KRAS, BRAF and HER2 mutations were assessed by MALDI-TOF MS (Cohort 1). EML4-ALK translocation was tested by Ventana method in EGFR-wild type patients (Cohort 2).

Results

From August 2011 to November 2013, a total of 1772 patients with lung adenocarcinoma were enrolled. In Cohort 1 analysis, EGFR, KRAS, HER2 and BRAF mutations were identified in 987 (55.7%), 93 (5.2%), 36 (2.0%) and 12 (0.7%) patients, respectively. Most of these mutations were mutually exclusive, except for co-mutations in seven patients (3 with EGFR + KRAS, 3 with EGFR + HER2 and 1 with KRAS + BRAF). In Cohort 2 analysis, 29 of 295 EGFR-wild type patients (9.8%) were positive for EML4-ALK translocation. EGFR mutations were more common in female patients and non-smokers and KRAS mutations were more common in male patients and smokers. Gender and smoking status were not correlated significantly with HER2, BRAF and EML4-ALK mutations. EML4-ALK translocation was more common in patients with younger age.

Conclusion

This was the first study in Taiwan to explore the incidence of five oncogenic drivers in patients with lung adenocarcinoma and the results could be valuable for physicians in consideration of targeted therapy and inclusion of clinical trials.     

Molecular Epidemiology of EGFR Mutations in Asian Patients with Advanced Non-Small-Cell Lung Cancer of Adenocarcinoma Histology – Mainland China Subset Analysis of the PIONEER study

Epidermal growth factor receptor (EGFR) mutations are the strongest response predictors to EGFR tyrosine kinase inhibitors (TKI) therapy, but knowledge of the EGFR mutation frequency on lung adenocarcinoma is still limited to retrospective studies. The PIONEER study (NCT01185314) is a prospective molecular epidemiology study in Asian patients with newly diagnosed advanced lung adenocarcinoma, aiming to prospectively analyze EGFR mutation status in IIIB/IV treatment-naïve lung adenocarcinomas in Asia. We report the mainland China subset results. Eligible patients (≥20 yrs old, IIIB/IV adenocarcinoma and treatment-naïve) were registered in 17 hospitals in mainland China. EGFR was tested for mutations by amplification refractory mutation system using biopsy samples. Demographic and clinical characteristics were collected for subgroup analyses. A total of 747 patients were registered. Successful EGFR mutation analysis was performed in 741, with an overall mutation rate of 50.2%. The EGFR active mutation rate is 48.0% (with 1.3% of combined active and resistance mutations). Tobacco use (>30 pack-year vs. 0–10 pack-year, OR 0.27, 95%CI: 0.17–0.42) and regional lymph nodes involvement (N3 vs. N0, OR 0.47, 95%CI: 0.29–0.76) were independent predictors of EGFR mutation in multivariate analysis. However, even in regular smokers, the EGFR mutation frequency was 35.3%. The EGFR mutation frequency was similar between diverse biopsy sites and techniques. The overall EGFR mutation frequency of the mainland China subset was 50.2%, independently associated with the intensity of tobacco use and regional lymph nodes involvement. The relatively high frequency of EGFR mutations in the mainland China subset suggest that any effort to obtain tissue sample for EGFR mutation testing should be encouraged.     

SNPs in the TGF-β Signaling Pathway Are Associated with Increased Risk of Brain Metastasis in Patients with Non–Small-Cell Lung Cancer

Purpose

Brain metastasis (BM) from non-small cell lung cancer (NSCLC) is relatively common, but identifying which patients will develop brain metastasis has been problematic. We hypothesized that genotype variants in the TGF-β signaling pathway could be a predictive biomarker of brain metastasis.

Patients and Methods

We genotyped 33 SNPs from 13 genes in the TGF-β signaling pathway and evaluated their associations with brain metastasis risk by using DNA from blood samples from 161 patients with NSCLC. Kaplan-Meier analysis was used to assess brain metastasis risk; Cox hazard analyses were used to evaluate the effects of various patient and disease characteristics on the risk of brain metastasis.

Results

The median age of the 116 men and 45 women in the study was 58 years; 62 (39%) had stage IIIB or IV disease. Within 24 months after initial diagnosis of lung cancer, brain metastasis was found in 60 patients (37%). Of these 60 patients, 16 had presented with BM at diagnosis. Multivariate analysis showed the GG genotype of SMAD6: rs12913975 and TT genotype of INHBC: rs4760259 to be associated with a significantly higher risk of brain metastasis at 24 months follow-up (hazard ratio [HR] 2.540, 95% confidence interval [CI] 1.204–5.359, P = 0.014; and HR 1.885, 95% CI 1.086–3.273, P = 0.024), compared with the GA or CT/CC genotypes, respectively. When we analyzed combined subgroups, these rates showed higher for those having both the GG genotype of SMAD6: rs12913975 and the TT genotype of INHBC: rs4760259 (HR 2.353, 95% CI 1.390–3.985, P = 0.001).

Conclusions

We found the GG genotype of SMAD6: rs12913975 and TT genotype of INHBC: rs4760259 to be associated with risk of brain metastasis in patients with NSCLC. This finding, if confirmed, can help to identify patients at high risk of brain metastasis.     

Increased Expression of TGFβR2 Is Associated with the Clinical Outcome of Non-Small Cell Lung Cancer Patients Treated with Chemotherapy

To investigate the prognostic significance of TGFβR2 expression and chemotherapy in Chinese non-small cell lung cancer (NSCLC) patients, TGFβR2 expression NSCLC was analyzed in silico using the Oncomine database, and subsequently analyzed with quantitative RT-PCR in 308 NSCLC biopsies, 42 of which were paired with adjacent non-neoplastic tissues. Our results show that TGFβR2 expression was also increased in NSCLC biopsies relative to normal tissue samples and correlated with poor prognosis. TGFβR2 expression was also significantly correlated with other clinical parameters such as tumor differentiation, invasion of lung membrane, and chemotherapy. Moreover, overall survival (OS) and disease free survival (DFS) was increased in patients with low TGFβR2 expressing NSCLC and who had undergone chemotherapy. Thus, high expression of TGFβR2 is a significant risk factor for decreased OS and DFS in NSCLC patients. Thus, TGFβR2 is a potential prognostic tumor biomarker for chemotherapy.     

let-7b and miR-126 Are Down-Regulated in Tumor Tissue and Correlate with Microvessel Density and Survival Outcomes in Non–Small–Cell Lung Cancer

Angiogenesis is a critical event in the development, progression, and spread of various human cancers, including lung cancer. Molecular mechanisms that underlie the complex regulation of angiogenic processes are poorly understood. However, an increasing body of evidence indicates miRNAs as important regulators of tumor angiogenesis. Forceps biopsies were collected from tumor tissue, surrounding tissue, and non-tumor tissue from 50 NSCLC patients. Lung tissue samples from individuals with no clinical evidence of a cancerous disease served as controls. Immunohistochemical staining for Factor VIII was used to evaluate microvessel density (MVD). TaqMan® primer-probe sets were used in quantitative real-time RT-PCR reactions to determine expression levels of let-7b, miR-126, miR-9, and miR-19a. We demonstrated significantly higher MVD and decreased expression levels of let-7b and miR-126 in tumor tissue and surrounding tissue in comparison to corresponding non-tumor tissue or lung tissue from the control group. In addition, no differences in MVD and expression levels of both miRNAs between tumor tissue and surrounding tissue from NSCLC patients were observed. Low expression of both miRNAs correlated with high MVD and worse progression-free survival and overall survival. These observations strongly suggest similar molecular alternations within tumor tissue and surrounding tissue that comprise a specific microenvironment. Low expression of let-7b and miR-126 seems to have a possible anti-angiogenic role in lung tumor tissue and significantly correlates with worse survival outcomes for lung cancer patients. Moreover, the regulation of let-7b and miR-126 expression could have therapeutic potential because it could reduce tumor angiogenesis and therefore suppress tumor growth in lung cancer patients.     

A Meta-Analysis of the Relationship Between RARβ Gene Promoter Methylation and Non-Small Cell Lung Cancer

Background

Hypermethylation of CpG islands in tumor suppressor gene plays an important role in carcinogenesis. Many studies have demonstrated that hypermethylation in promoter region of RARβ gene could be found with high prevalence in tumor tissue and autologous controls such as corresponding non-tumor lung tissue, sputum and plasma of the NSCLC patients. But with the small number subjects included in the individual studie, the statistical power is limited. Accordingly, we performed this meta-analysis to further asses the relationship of methylation prevalence between the cancer tissue and atuologous controls (corresponding non-tumor lung tissue, sputum and plasma).

Methods

The published articles about RARβ gene promoter hypermethyltion were identified using a systematic search strategy in PubMed, EMBASE and CNKI databases. The pooled odds ratio (OR) of RARβ promoter methylation in lung cancer tissue versus autologous controls were calculated.

Results

Finally, eleven articles, including 1347 tumor tissue samples and 1137 autologous controls were included in this meta-analysis. The pooled odds ratio of RARβ promoter methylation in cancer tissue was 3.60 (95%CI: 2.46–5.27) compared to autologous controls with random-effect model. Strong and significant correlation between tumor tissue and autologous controls of RARβ gene promoter hypermethylation prevalence across studies (Correlation coefficient 0.53) was found.

Conclusion

RARβ promoter methylation may play an important role in carcinogenesis of the NSCLC. With significant methylation prevalence correlation between tumor tissue and autologous of this gene, methylation detection may be a potential method for searching biomarker for NSCLC.     

The Prognostic Role of the Class III β-Tubulin in Non-Small Cell Lung Cancer (NSCLC) Patients Receiving the Taxane/Vinorebine-Based Chemotherapy: A Meta-Analysis

Background

A number of studies have examined the relationship between the expression of the class III β-tubulin (TUBB3) and the treatment responses to the taxane/vinorebine-based chemotherapy in patients with non-small cell lung cancer (NSCLC). However, the results of these studies were inconsistent and inconclusive. Therefore, we conducted an up-to-date meta-analysis to evaluate the prognostic role of TUBB3 in the taxane/vinorebine-based chemotherapy.

Methods

A literature search for relevant studies was conducted in PubMed, Embase, and CNKI. The inclusion criteria were the taxane/vinorebine-based chemotherapy in patients with NSCLC and the evaluation of the clinical outcomes in relation to the expression of TUBB3. The clinical outcomes analyzed in this study included the overall response rate (ORR), overall survival (OS), and event-free survival (EFS). Odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) were calculated to assess the risk associated with the TUBB3 expression in the taxane/vinorebine-based chemotherapy.

Results

A total of 28 studies with 2401 NSCLC patients were qualified for this meta-analysis. We found that the positive or high level of TUBB3 expression was associated with a poorer ORR (OR = 0.24, 95% CI = 0.16–0.36, p<0.001), an unfavorable OS (HR = 1.52, 95% CI = 1.27–1.82, p<0.001), and a worse EFS (HR = 1.47, 95% CI = 1.24–1.74, p<0.001) compared to the negative or low level of TUBB3 expression. The statistically significant associations between TUBB3 and chemotherapy responses were also observed in the stratified subgroup analysis, which included the analysis by ethnic subgroup (Asian and Caucasian), chemotherapy regimen (taxane-based and vinorebine-based), TUBB3 detection method (IHC and PCR), and treatment strategy (surgery plus adjuvant chemotherapy and palliative chemotherapy).

Conclusions

The expression level of TUBB3 may be a useful biomarker to predict the clinical outcomes of the taxane/vinorebine-based chemotherapy in patients with NSCLC.