Krishna Bajee Sriram

Common pathogenic mechanisms and pathways in the development of COPD and lung cancer

Introduction: Lung cancer and COPD commonly coexist in smokers, and the presence of COPD increases the risk of developing lung cancer. In addition to smoking cessation and preventing smoking initiation, understanding the shared mechanisms of these smoking-related lung diseases is critical, in order to develop new methods of prevention, diagnosis and treatment of lung cancer and COPD. Areas covered: This review discusses the common mechanisms for susceptibility to lung cancer and COPD, which in addition to cigarette smoke, may involve inflammation, epithelial–mesenchymal transition, abnormal repair, oxidative stress, and cell proliferation. Furthermore, we discuss the underlying genomic and epigenomic changes (single nucleotide polymorphisms (SNPs), copy number variation, promoter hypermethylation and microRNAs) that are likely to alter biological pathways, leading to susceptibility to lung cancer and COPD (e.g., altered nicotine receptor biology). Expert opinion: Strategies to study genomics, epigenomics and gene-environment interaction will yield greater insight into the shared pathogenesis of lung cancer and COPD, leading to new diagnostic and therapeutic modalities.

Diagnostic molecular biomarkers for malignant pleural effusions

Malignant pleural effusions (MPEs) are a common and important cause of cancer-related mortality and morbidity. Prompt diagnosis using minimally invasive tests is important because the median survival after diagnosis is only 4-9 months. Pleural fluid cytology is pivotal to current MPE diagnostic algorithms but has limited sensitivity (30-60%). Consequently, many patients need to undergo invasive diagnostic tests such as thoracoscopic pleural biopsy. Recent genomic, transcriptomic, methylation and proteomic studies on cells within pleural effusions have identified novel molecular diagnostic biomarkers that demonstrate potential in complementing cytology in the diagnosis of MPEs. Several challenges will need to be addressed prior to the incorporation of these molecular tests into routine clinical diagnosis, including validation of molecular diagnostic markers in well-designed prospective, comparative and cost-effectiveness studies. Ultimately, minimally invasive diagnostic tests that can be performed quickly will enable clinicians to provide the most effective therapies for patients with MPEs in a timely fashion.

Whole genome sequencing for lung cancer

Lung cancer is a leading cause of cancer related morbidity and mortality globally, and carries a dismal prognosis. Improved understanding of the biology of cancer is required to improve patient outcomes. Next-generation sequencing (NGS) is a powerful tool for whole genome characterisation, enabling comprehensive examination of somatic mutations that drive oncogenesis. Most NGS methods are based on polymerase chain reaction (PCR) amplification of platform-specific DNA fragment libraries, which are then sequenced. These techniques are well suited to high-throughput sequencing and are able to detect the full spectrum of genomic changes present in cancer. However, they require considerable investments in time, laboratory infrastructure, computational analysis and bioinformatic support. Next-generation sequencing has been applied to studies of the whole genome, exome, transcriptome and epigenome, and is changing the paradigm of lung cancer research and patient care. The results of this new technology will transform current knowledge of oncogenic pathways and provide molecular targets of use in the diagnosis and treatment of cancer. Somatic mutations in lung cancer have already been identified by NGS, and large scale genomic studies are underway. Personalised treatment strategies will improve care for those likely to benefit from available therapies, while sparing others the expense and morbidity of futile intervention. Organisational, computational and bioinformatic challenges of NGS are driving technological advances as well as raising ethical issues relating to informed consent and data release. Differentiation between driver and passenger mutations requires careful interpretation of sequencing data. Challenges in the interpretation of results arise from the types of specimens used for DNA extraction, sample processing techniques and tumour content. Tumour heterogeneity can reduce power to detect mutations implicated in oncogenesis. Next-generation sequencing will facilitate investigation of the biological and clinical implications of such variation. These techniques can now be applied to single cells and free circulating DNA, and possibly in the future to DNA obtained from body fluids and from subpopulations of tumour. As costs reduce, and speed and processing accuracy increase, NGS technology will become increasingly accessible to researchers and clinicians, with the ultimate goal of improving the care of patients with lung cancer.

Array-Comparative Genomic Hybridization Reveals Loss of SOCS6 Is Associated with Poor Prognosis in Primary Lung Squamous Cell Carcinoma

Background Primary tumor recurrence commonly occurs after surgical resection of lung squamous cell carcinoma (SCC). Little is known about the genes driving SCC recurrence. Methods We used array comparative genomic hybridization (aCGH) to identify genes affected by copy number alterations that may be involved in SCC recurrence. Training and test sets of resected primary lung SCC were assembled. aCGH was used to determine genomic copy number in a training set of 62 primary lung SCCs (28 with recurrence and 34 with no evidence of recurrence) and the altered copy number of candidate genes was confirmed by quantitative PCR (qPCR). An independent test set of 72 primary lung SCCs (20 with recurrence and 52 with no evidence of recurrence) was used for biological validation. mRNA expression of candidate genes was studied using qRT-PCR. Candidate gene promoter methylation was evaluated using methylation microarrays and Sequenom EpiTYPER analysis. Results 18q22.3 loss was identified by aCGH as being significantly associated with recurrence (p = 0.038). Seven genes within 18q22.3 had aCGH copy number loss associated with recurrence but only SOCS6 copy number was both technically replicated by qPCR and biologically validated in the test set. SOCS6 copy number loss correlated with reduced mRNA expression in the study samples and in the samples with copy number loss, there was a trend for increased methylation, albeit non-significant. Overall survival was significantly poorer in patients with SOCS6 loss compared to patients without SOCS6 loss in both the training (30 vs. 43 months, p = 0.023) and test set (27 vs. 43 months, p = 0.010). Conclusion Reduced copy number and mRNA expression of SOCS6 are associated with disease recurrence in primary lung SCC and may be useful prognostic biomarkers.

Screening for activating EGFR mutations in surgically resected nonsmall cell lung cancer.

The clinical applicability of screening surgically resected nonsmall cell lung cancer (NSCLC) tumour tissue and serum for activating epidermal growth factor receptor (EGFR) mutation is unknown. Furthermore, the comparative accuracy of inexpensive EGFR mutation tests, mutant-enriched (ME)-PCR and high-resolution melt (HRM) has not been determined. Lung tumour DNA from 522 surgically resected stage I–IV NSCLC and matched serum DNA from a subset of 64 subjects was analysed for EGFR mutations in exons 19 and 21 using ME-PCR and HRM. Additionally, 97 subjects had previous EGFR DNA sequencing data available for comparison. ME-PCR and HRM detected EGFR mutations in 5% (27 out of 522) of tumour samples. Compared to DNA sequencing, ME-PCR had a sensitivity of 100% and specificity of 99%, while HRM had 100% sensitivity and specificity. Six subjects with EGFR mutation tumours had matched serum, where ME-PCR detected mutations in three samples and HRM in two samples. In the cohort of never-smoker subjects, those with EGFR mutated tumours had worse survival compared with wild-type tumours (30 versus 49 months; p=0.017). ME-PCR and HRM have similar accuracy in detecting EGFR mutations but the prognostic implications of the mutations in resected NSCLC warrants further study.

Pleural fluid cell-free DNA integrity index to identify cytologically negative malignant pleural effusions including mesotheliomas

BackgroundThe diagnosis of malignant pleural effusions (MPE) is often clinically challenging, especially if the cytology is negative for malignancy. DNA integrity index has been reported to be a marker of malignancy. The aim of this study was to evaluate the utility of pleural fluid DNA integrity index in the diagnosis of MPE.MethodsWe studied 75 pleural fluid and matched serum samples from consecutive subjects. Pleural fluid and serum ALU DNA repeats [115bp, 247bp and 247bp/115bp ratio (DNA integrity index)] were assessed by real-time quantitative PCR. Pleural fluid and serum mesothelin levels were quantified using ELISA.ResultsBased on clinico-pathological evaluation, 52 subjects had MPE (including 16 mesotheliomas) and 23 had benign effusions. Pleural fluid DNA integrity index was higher in MPE compared with benign effusions (1.2 vs. 0.8; p<0.001). Cytology had a sensitivity of 55% in diagnosing MPE. If cytology and pleural fluid DNA integrity index were considered together, they exhibited 81% sensitivity and 87% specificity in distinguishing benign and malignant effusions. In cytology-negative pleural effusions (35 MPE and 28 benign effusions), elevated pleural fluid DNA integrity index had an 81% positive predictive value in detecting MPEs. In the detection of mesothelioma, at a specificity of 90%, pleural fluid DNA integrity index had similar sensitivity to pleural fluid and serum mesothelin (75% each respectively).ConclusionPleural fluid DNA integrity index is a promising diagnostic biomarker for identification of MPEs, including mesothelioma. This biomarker may be particularly useful in cases of MPE where pleural aspirate cytology is negative, and could guide the decision to undertake more invasive definitive testing. A prospective validation study is being undertaken to validate our findings and test the clinical utility of this biomarker for altering clinical practice.

Genomic medicine in non-small cell lung cancer: Paving the path to personalized care

Lung cancer is the commonest cause of cancer‐related mortality and non‐small cell lung cancer (NSCLC) accounts for 80% of all lung cancer. The prognosis of NSCLC remains poor across all stages, despite advances in staging techniques and treatments. The findings of recent high‐throughput mRNA microarray studies have shown potential in refining current NSCLC diagnosis, classification, prognosis and treatment paradigms. Emerging microarray studies of microRNA, DNA copy number and methylation profiles are also providing novel insights into the biology of NSCLC. Currently there are several challenges, such as the reproducibility and cost of microarray platforms that will need to be addressed prior to the implementation of these genomic technologies to routine thoracic oncology practice. In addition, genomic tests (such as prognosis and prediction gene expression signatures) will need to be validated in well designed prospective studies that aim to answer clinically relevant questions. If successful, the integration of microarray‐based genomic information with existing clinicopathological models may enhance the ability of clinicians to match the most effective treatment to an individual patient. Such a strategy may improve survival and reduce treatment‐related morbidity in NSCLC patients.

Metastatic small-cell lung cancer presenting as fulminant hepatic failure

We report a case of a 75-year-old woman with fulminant hepatic failure due to metastatic small-cell lung cancer (SCLC). The patient was hospitalised for the management of rapidly progressive hepatic failure. Thoracic radiology identified a widened mediastinum, and prior to hospitalisation she had received antibiotics for a urinary tract infection. Consequently, her hepatic failure was deemed to be due to either sarcoidosis with hepatic involvement or an antibiotic-related adverse event and was treated with prednisolone. However, the patients clinical condition continued to deteriorate and a liver biopsy was obtained. Histopathology and immunohistochemistry tests demonstrated almost complete parenchymal replacement with metastatic SCLC. The patient was considered to be too unwell to receive chemotherapy and hence received best supportive care instead, and died shortly thereafter.

Evaluation of the Patterns of Care Provided to Patients With COPD Compared to Patients With Lung Cancer Who Died in Hospital

Introduction: There is limited information about the end-of-life care provided to patients with end-stage chronic obstructive pulmonary disease (COPD) in comparison to patients with lung cancer. Aim and Methods: We compared the end-of-life care provided to patients with COPD versus patients with lung cancer who died in hospital over a 12-month period in our institution. Results: During the study period, 89 patients died due to COPD (n = 34) or lung cancer (n = 55). Compared to patients with lung cancer, patients with COPD received less palliative care services (50% vs 9%, P < .001) and underwent more diagnostic tests and received more life-prolonging measures. Conclusion: Toward the end of their life, patients with COPD received fewer symptom-alleviating treatments and palliative care services.

Suboptimal inhaler medication adherence and incorrect technique are common among chronic obstructive pulmonary disease patients.

Patients with chronic obstructive pulmonary disease (COPD) are routinely prescribed one or more inhaled medications. Adherence to inhaler medications and correct inhaler device technique are crucial to successful COPD management. The goals of this study were to estimate adherence and inhaler technique in a cohort of COPD patients. This was an observational study conducted on a sample of 150 COPD patients. Medication adherence was assessed using the Medication Adherence Report Scale (MARS). Inhaler technique was assessed using standardized checklists. Clinical data were collected using a proforma. Of the 150 patients (mean age 70.3 years, 52% male), 58% reported suboptimal adherence (MARS ≤ 24). High adherence to therapy (MARS = 25) was associated with older age (p = 0.001), but not any of the other studied variables. Medication non-adherence was not associated with COPD exacerbations. Errors (≥ 1) in inhaler technique were common across all of the types of inhaler devices reportedly used by patients, with the highest proportion of errors among Turbuhaler users (83%) and the least proportion of errors among Handihaler users (50%). No clinical variables were associated with errors in inhaler technique. Suboptimal adherence and errors in inhaler technique are common among COPD patients. No clinical variables to assist in the prediction of medication non-adherence and poor inhaler technique were identifiable. Consequently, regular assessment of medication adherence and inhaler technique should be incorporated into routine clinical practice to facilitate improved health outcomes among patients with COPD.