EGFR expression as an ancillary tool for diagnosing lung cancer in cytology specimens

Current advances in prognostic and diagnostic biomarkers for solid cancers: Detection techniques and future challenges

Solid cancers are one of the leading causes of cancer related deaths, characterized by rapid growth of tumour, and local and distant metastases. Current advances on multimodality care have substantially improved local control and metastasis-free survival of patients by resection of primary tumour. The major concern in disease prognosis is the timely detection of resectable or metastatic tumour, thus reinforcing the need for identification of biomarkers for premalignant lesions of solid cancer. This ultimately improves the outcome for the patients. Therefore, the purpose of this review is to update the recent advancements on prognostic and diagnostic biomarkers to enhance early detection of common solid cancers including, breast, lung, colorectal, prostate and stomach cancer. We also provide an insight into Food and Drug Administration (FDA)-approved solid cancers biomarkers; various conventional techniques used for detection of prognostic and diagnostic biomarkers and discuss approaches to turn challenges in this field into opportunities.

Sensitivity of Cytology Specimens From Bronchial Aspirate or Washing During Bronchoscopy in the Diagnosis of Lung Malignancies: An Update

BACKGROUND

Routine collection of cytology specimens from bronchial aspirate or washing is thought to increase the sensitivity of bronchoscopy for diagnosing malignant lung lesions. However, the added value of this practice has not been reappraised in a context of changing epidemiology.

PATIENTS AND METHODS

In a retrospective monocenter study, all cytology specimens from bronchial aspirate or washing collected between May 2011 and December 2014 and the corresponding patients' files were reviewed. The final diagnosis of malignancy was based on all available pathologic information.

RESULTS

Bronchoscopy was performed in 2750 patients, and bronchial cytology specimens were collected during 667 procedures, including 474 aspirate or washing cytology specimens collected during conventional (n = 366) or ultrasound-guided (EBUS) (n = 108) bronchoscopy in 455 patients with malignant lung lesion(s). The predominant histologic types were lung adenocarcinoma (43.9%) and squamous cell carcinoma (25.2%), and 271 tumors (59.6%) were endoscopically visible. At least 1 endoscopic sample (bronchial cytology and/or biopsies and/or endobronchial ultrasound-guided samples) was positive for malignancy during 329 (69.4%) of the 474 endoscopies, including 79 samples obtained in nonvisible lesions. Only 67 bronchial cytology specimens proved positive (sensitivity, 14.7%; 95% confidence interval, 11.8%-18.3%), and only 1 specimen (0.2%) produced a diagnosis not made by other samples during the same procedure.

CONCLUSION

In contrast with older studies, the added value of collecting cytology specimens from bronchial aspirate or washing during bronchoscopy in this series proved negligible, reflecting mainly the increasing prevalence of adenocarcinomas. Abandoning this technique could be considered in centers with similar expertise and patient populations.

Comparative analysis of cell morphology in sputum samples homogenized with dithiothreitol, N-acetyl-L cysteine, Cytorich(®) red preservative and in cellblock preparations to enhance the sensitivity of sputum cytology for the diagnosis of lung cancer

BACKGROUND

Lung cancer claims highest rate of cancer related mortality worldwide, mainly due to late diagnosis and distant metastasis. Sputum cytology is the simplest, non-invasive and cost effective technique but it has low sensitivity due to lack of robust processing methods to retrieve all the diagnostic materials clogged in mucus, inflammatory exudates and blood.

METHODS

This study have compared conventional pick and smear method of sputum processing with samples prepared by homogenization methods using N-acetyl-l-cysteine, Dithiothreitol (DTT), CytoRich red solution and cell blocks (CBs) with respect to screening time, quality of staining, cellularity, smear background, nuclear and cytoplasmic morphology preservation, and diagnostic efficacy. The significance of CB prepared from homogenised samples for immunocytochemistry, protein extraction, Genomic DNA and RNA extraction were also evaluated on a cohort 3,185 samples. The significance of the morphological features in each of the techniques was statistically analysed using SPSS 11 software.

RESULTS

The smear background clarity, staining quality and diagnostic efficacy of samples processed in red solution was found to be superior to the conventional method (P < 0.0001), where as samples homogenized in DTT showed a better cellularity (P < 0.0001). CBs prepared from samples homogenized in red solution were found to be very significant (P < 0.0001) in increasing the diagnostic efficacy compared to other two methods. Immunocytochemistry and DNA extraction were found possible in CBs as well as from the cell suspension. A combined analysis of smears and CBs found to improve the sensitivity of sputum cytology.

CONCLUSION

The study suggests homogenization of sputum in CytoRich ® red solution and cellblock preparations routinely for all samples to improve the sensitivity of sputum cytology. IHC and DNA extraction can be performed in sputum samples suggesting the role of sputum samples for ancillary techniques.

Detection of lung cancer using multiple genetic markers--a systematic review

Lung cancer is the leading cause of cancer deaths worldwide, and has one of the lowest survival rates of any solid tumor. In recent years, several attempts have been conducted to improve an early or accelerated diagnosis due to better overall prognosis after therapy. The aim of this study was evaluating the use of genetic markers for diagnosis of lung cancer. This study was conducted in accordance to Transparent Reporting of Systematic Reviews and Meta-Analyses. Three Internet sources were used to search: MEDLINE-PubMed, EMBASE, and LILACS. The databases were searched for studies conducted in the period up to and including May 10, 2011. The following inclusion criteria were applied: lung cancer studies, and the use of genetic markers for diagnosis. Studies using animal models, review articles, meta-analyses, abstracts, conference proceedings, editorials/letters, case reports, incorrect study population, inadequate data, and cytology was not obtained, were excluded. A total of 1,901 abstracts/citations were identified for preliminary review. From 24 final selected studies, 17 referred to chromosomal markers diagnosis, eight to genes as marker, and one to both subjects. Fluorescence in situ hybridization (FISH) was applied in all studies. Despite the limitations of this study, application of genetic markers to lung cancer diagnosis seems to have prognosis value irrespective of detection methodology used. FISH was the main technique applied to diagnose genetics alterations and revealed a high specificity, although some authors reported low sensitivity.

EGFR gene status in cytological samples of nonsmall cell lung carcinoma: controversies and opportunities

BACKGROUND

In nonsmall cell lung cancer (NSCLC), the development and clinical application of tyrosine kinase inhibitors (TKIs) targeting the epidermal growth factor receptor (EGFR) has required the investigation of EGFR status by gene copy number and/or mutation analysis. This review aimed to present the current knowledge of the use of cytological specimens for EGFR testing in lung cancer.

METHODS

A systematic computerized search was performed of the MEDLINE(R) and EMBASE databases to identify articles reporting the use of cytological samples for determining EGFR status in NSCLC.

RESULTS

Data were extracted from 30 original articles. An additional 19 reviews, consensus statements, and editorials were selected from 175 retrieved papers. Different techniques using cell blocks, scraped cells from archival slides, and fresh cells have shown promising results and include fluorescent in situ hybridization (FISH), direct sequencing, and quantitative polymerase chain reaction (PCR), with similar or higher accuracy and sensitivity than surgical specimens. Preservation and quality of the extracted DNA seem to matter more than the actual number of tumor cells present in the samples. However, major issues still reside in the amount of material, the interference from background non-neoplastic cells, and standardization of parameters for cytological samples.

CONCLUSIONS

This analysis provided evidence that cytological material is suitable for detecting EGFR status using several different methodologies and preparations. New prospective, clinical studies are encouraged for collection and handling of cytological samples as well as for validation of novel techniques in large cohorts.

Screening for EGFR mutations in lung cancer, a report from India

Epidermal growth factor receptor (EGFR) is one of the targeted molecular markers in many cancers including the lung malignancy. Genetic modifications such as deletions, insertions and Single Nucleotide Polymorphisms in the tyrosine kinase (TK) domain of EGFR is a common feature observed in most lung cancers. Gefitinib and erlotinib are commonly available therapeutic drugs which act as specific inhibitors for the tyrosine kinase domain of EGFR and associated with EGFR mutations in exons 18-21. However the prevalence of mutation varies among ethnicity, grade, age and gender. This is the first report on the prevalence of EGFR mutation in non-small cell lung cancer patients using DNA obtained from samples such as biopsy/cytology/pleural fluid and Fine Needle Aspiration (FNA), across India. We have screened for 29 somatic mutations which span exons 18, 19, 20 and 21 of EGFR gene using Scorpion probe based ARMS-PCR technique. DNA from 220 NSCLC tissue samples were analyzed for EGFR mutations and mutations were detected in 51.8% of the study population. Among the mutant positive cases, the deletions in exon 19 (52%) and a missense mutation L858R in exon 21 (26%) were most predominant. There was a significant increase in overall mutations (p=0.01) as a function of age, mutation in exons 19 and 21 together (p=0.003), mutations in exons 18, 19 and 21 (p=0.04) and mutations in exons 18 and 19 (p=0.03) in females. Mutations did not seem to significantly correlate metastases or disease progression. Mutations in exons [19] and 21 together were significant in non-smokers compared to smokers (p=0.01) using Mann-Whitney tests. The study suggests high prevalence of EGFR positivity in NSCLC in Indian sub-population and provides opportunities for targeted therapies for this group.

[Molecular characteristics of lung cancer]

While no real improvement in the long term survival has been obtained in lung cancer, during this decade a significant improvement in cancer control has been obtained by biology driven targeted therapy as with anti EGFR tyrosine kinase. Two phases can be described in the knowledge of lung cancer biology: a first phase open in the 1980s describing the main molecular anomalies and impaired cell control mechanisms, and a second phase starting in the 2004-2005 giving rise to the therapeutic applications of this knowledge. A new molecular classification of lung cancer, particularly adenocarcinomas will soon be proposed for therapeutic application.

Cigarette smoke induces epidermal growth factor receptor-dependent redistribution of apical MUC1 and junctional beta-catenin in polarized human airway epithelial cells

Cigarette smoke (CS) accounts for nearly 90% of lung cancer deaths worldwide; however, an incomplete understanding of how CS initiates preneoplastic changes in the normal airway hinders early diagnosis. Short-term exposure to CS causes aberrant activation of epidermal growth factor receptor (EGFR) and canonical Wnt/beta-catenin signaling pathways in human bronchial epithelial (HBE) cells. We hypothesize that this response is elicited through the disruption of spatially segregated cell membrane proteins in the polarized airway epithelium. Using an in vitro model of highly differentiated HBE cells, we observed membrane characteristics consistent with the native airway, including the presence of a membrane mucin, MUC1, at the apical cell pole, beta-catenin at the apical-lateral membrane, and EGFR at the basolateral membrane. Following exposure to smoke, intercellular spaces enlarge and cilia disappear. This histopathology is accompanied by molecular events that include perinuclear trafficking of basolateral EGFR, EGFR phosphorylation, pEGFR-mediated phosphorylation of MUC1's cytoplasmic tail (CT), loss of E-cadherin/beta-catenin complexes at the adherens junctions (AJs), intracellular formation and nuclear shuffling of beta-catenin/MUC1-CT complexes, and, ultimately, up-regulation and nuclear localization of Wnt nuclear effector, Lef-1. In the presence of EGFR inhibitor, AG1478, CS-induced histopathology and molecular events were inhibited. These data point to EGFR as a portal through which CS mediates its damaging effects on AJ-mediated cell polarity and activation of canonical Wnt/beta-catenin signaling.

Molecular pathology--translating research into clinical practice: an expanding frontier in surgical oncology

Molecular assays have now become essential to the pathologist and clinician alike in diagnosing and managing disease. This article highlights the techniques and molecular targets no longer ancillary to basic research. Ripe for discussion are the likely future impact of genetics on clinical care, the potential models for service provision, and the broader ethical, legal, and social issues related to the use of genetic information for nonmedical purposes. Molecular methods are forecasted to increase in assisting in the diagnosis of human diseases. The author's mission is to embrace this discipline and use these technologies in clinical practice.