Faculty Bibliography

Introduction: Endobronchial ultrasound-guided transbronchial needle aspiration(EBUS-TBNA) is utilized for the diagnosis and staging of mediastinal lesions. However, currently no consensus identifies the quantity of tissue or the number of immunhisotchemical (IHC) staining required for the processing of common molecular mutation profiles. In collaboration with out cytopathology department we developed and implemented a two-step protocol to optimize tissue sampling. First, we mandated two additional passes after a tissue specimen has been deemed diagnostic by rapid on-site cytopathologic examinations (ROSE). Second, the cytology department implemented a tissue-sparing algorithm proposed by Mukhopadhyay and Katzenstein to further characterize non-small cell lung cancer (NSCLC). The purpose of this study is to evaluate the effectiveness of the algorithm to yield adequate tissue for molecular mutation profiling. Methods: This retrospective study reviewed all patients who had undergone EBUS-TBNA at NYU Langone Medical Center from January 2009 to July 2012. The study identified patients with a diagnosis of lung adenocarcinoma or unclassifiable NSCLC. Excluded from this study were adenocarcinoma of non-lung origin and negative lymph nodes. For Each EBUS-TBNA sampling we documented patient's baseline characteristics, size and location of lymph nodes, number of needle passes, and the number of IHC stains. Analyses were also made to compare data before and after July 2011, when a new implemented two-step protocol took place. Results: 293 patients underwent EBUS-TBNA, and thirty-four patients were diagnosed with lung adenocarcinoma or NSCLC-NOS. Thirteen patients had molecular mutation testing completed. Prior to July 2011, 1/19 patients had molecular mutation profiles compared to 12/14 patients after July 2011. Several factors increased the success of the protocol, such as lymph node size and number of IHC stains. Average lymph node size for adequate tissue sampling was 25.1mm compared to 18.0mm (p value <0.05). Minimization of IHC staining was also significant. Specimens that yielded molecular profiles involved IHC staining limited to mean of 3.0 slides vs 5.4 slides (p value <0.05). Conclusion: The results of this study shows that utility of EBUS-TBNA to obtain molecular mutation profile is associated with lymph node size and IHC staining. The implementation of our algorithm significantly increased the number of patients with adequate tissue to complete molecular mutation profiles

Rationale: Cigarette smoke causes a field of injury and molecular changes in the airways even in histologically normal areas termed "field cancerization" which describes the site(s) of neoplasia and adjacent normal tissue with molecular abnormalities in common. MicroRNAs ( miRNAs) are small, non-coding RNAs that act as post-transcriptional regulators of gene expression by recognizing target sites in the 3' untranslated regions (3'UTRs) via incomplete base-pairing and induce mRNA degradation or translational repression. Deregulation of miRNAs has been linked to cancer initiation and progression, and miRNAs may act as tumor suppressor genes or oncogenes. We hypothesized that miRNA expression in the peripheral airways of smokers with lung cancer is distinct from that of smokers without lung cancer and therefore, miRNAs can be used as biomarkers for the early detection of lung cancer. Methods: We collected human peripheral airway epithelial cells by bronchoscopic brushing from the unaffected lung of thirteen smokers with lung adenocarcinoma and twelve control smokers. Total RNA was extracted from the peripheral airway epithelial cells by miRNAeasy and miRNA profiling was performed using the TaqMan Quantitative qRT-PCR miRNA Assay. Results: Comparison of miRNA levels in peripheral airway epithelial cells from smokers with or without lung cancer demonstrated 53 miRNAs that were significantly different (p<0.05) between the two groups. The majority of miRNAs were up-regulated (41 miRNAs) in lung cancer patients, including miR-21, miR-26a, miR-31, miR-34c, and miR-205. Down-regulated miRNAs included let-7b, let-7e, and miR-126. Several of the miRNAs with increased expression are of interest: miR-21 inhibits tumor suppressor protein PTEN, miR-26a suppresses PTEN and increases AKT phosphorylation and nuclear factor kappaB (NFkappaB) activation, miR-31 represses tumor suppressor genes LATS2 and PPP2R2A, miR-205 is associated with cancer relapses, and miR-34c, a p53 target induced by DNA damage, suggests the involvement of p53 pathway in field carcinogenesis. Down-regulated let-7b leads to higher expression of CYP2J2 and decreased miR-126 enhances adhesion, migration and invasion through increased Crk protein. Further gene expression and pathway analyses will corroborate the relationship between miRNAs and predicted pathways in real time. Conclusion: We discovered a profile of miRNAs in the contralateral lung of patients with lung cancer as biomarkers of field cancerization in smokers with lung adenocarcinoma. Further knowledge of field cancerization may lead to better understanding of tumorigenesis and development of biomarkers for early lung cancer detection

Lung cancer is the leading cause of cancer deaths worldwide largely owing to diagnosis of the disease at an advanced stage. Recent advances in blood-based biomarker research have the potential to reduce mortality by providing a means for detecting lung cancer at an earlier stage. Since the publication of the National Lung Cancer Screening Trial demonstrating reduction in mortality with computed tomography (CT) scan screening, the U.S. Preventive Services Task Force has released a draft statement recommending annual low-dose CT scan screening for high-risk patients. However, CT screening has a high false-positive rate leading to the need for additional imaging and invasive procedures. In this article, we review recent literature on blood-based lung cancer biomarkers that we believe will have a significant role in enhancing screening efficacy in the near future.

BACKGROUND: Low-dose computed tomography (CT) for lung cancer screening can reduce lung cancer mortality. The National Lung Screening Trial reported a 20% reduction in lung cancer mortality in high-risk smokers. However, CT scanning is extremely sensitive and detects non-calcified nodules (NCNs) in 24-50% of subjects, suggesting an unacceptably high false-positive rate. We hypothesized that by reviewing demographic, clinical and nodule characteristics, we could identify risk factors associated with the presence of nodules on screening CT, and with the probability that a NCN was malignant. METHODS: We performed a longitudinal lung cancer biomarker discovery trial (NYU LCBC) that included low-dose CT-screening of high-risk individuals over 50 years of age, with more than 20 pack-year smoking histories, living in an urban setting, and with a potential for asbestos exposure. We used case-control studies to identify risk factors associated with the presence of nodules (n = 625) versus no nodules (n = 557), and lung cancer patients (n = 30) versus benign nodules (n = 128). RESULTS: The NYU LCBC followed 1182 study subjects prospectively over a 10-year period. We found 52% to have NCNs >4 mm on their baseline screen. Most of the nodules were stable, and 9.7% of solid and 26.2% of sub-solid nodules resolved. We diagnosed 30 lung cancers, 26 stage I. Three patients had synchronous primary lung cancers or multifocal disease. Thus, there were 33 lung cancers: 10 incident, and 23 prevalent. A sub-group of the prevalent group were stable for a prolonged period prior to diagnosis. These were all stage I at diagnosis and 12/13 were adenocarcinomas. CONCLUSIONS: NCNs are common among CT-screened high-risk subjects and can often be managed conservatively. Risk factors for malignancy included increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking. A sub-group of screen-detected cancers are slow-growing and may contribute to over-diagnosis and lead-time biases.