Low tumour cell content in a lung tumour bank: implications for molecular characterisation.

Lung cancer encompasses multiple malignant epithelial tumour types, each with specific targetable, potentially actionable mutations, such that precision management mandates accurate tumour typing. Molecular characterisation studies require high tumour cell content and low necrosis content, yet lung cancers are frequently a heterogeneous mixture of tumour and stromal cells. We hypothesised that there may be systematic differences in tumour cell content according to histological subtype, and that this may have implications for tumour banks as a resource for comprehensive molecular characterisation studies in lung cancer. To investigate this, we estimated tumour cell and necrosis content of 4267 samples resected from 752 primary lung tumour specimens contributed to a lung tissue bank. We found that banked lung cancer samples had low tumour cell content (33%) generally, although it was higher in carcinoids (77.5%) than other lung cancer subtypes. Tumour cells comprise a variable and often small component of banked resected tumour samples, and are accompanied by stromal reaction, inflammation, fibrosis, and normal structures. This has implications for the adequacy of unselected tumour bank samples for diagnostic and molecular investigations, and further research is needed to determine whether tumour cell content has a significant impact on analytical results in studies using tissue from tumour bank resources.

Brief Tailored Smoking Cessation Counseling in a Lung Cancer Screening Population is Feasible: A Pilot Randomized Controlled Trial.

INTRODUCTION: Maximizing smoking abstinence in lung cancer screening participants is important to reduce individual risk of disease and improve screening cost-effectiveness; however, the optimal strategy remains undefined. We hypothesized that a single session of tailored face-to-face counseling on the day of screening CT scan, coupled with audio and printed cessation information would be feasible to deliver in a CT screening trial. METHODS: We randomized volunteer smokers in the Queensland Lung Cancer Screening Study to intervention (counseling session, audio quit materials, printed quit materials, Quitline contact details) or control group (printed quit materials, Quitline contact details). Participants self-reported point prevalence quit rates at 1 year. RESULTS: Fifty-five smokers were enrolled; 28 randomized to intervention and 27 controls. Median cigarette consumption was 25/day; 54/55 smoked at least 15 cigarettes per day. Median smoking duration was 46 years. Median Fagerström dependence score was 6. In total 58% did not report any quit attempt in the prior 12 months. Mean duration of counseling was 26.5 minutes. After 1 year, four participants (14.3%) in the intervention group and five participants (18.5%) in the control group had quit (P = .74). Combined annual point prevalence quit rate was 16.4%. CONCLUSIONS: Although feasible to deliver a single session of tailored counseling on the day of screening this intervention had no discernible impact on cessation over and above printed materials and Quitline access. As participants exhibited hardcore smoking characteristics, more intensive strategies, in larger cohorts, should be explored. IMPLICATIONS: The optimal smoking cessation strategy within a lung cancer screening program is not known. This study demonstrates that a single session of counseling can be feasibly delivered on the day of screening but may not have been intensive enough for long-term, hard-core smokers.

Screen-detected subsolid pulmonary nodules: long-term follow-up and application of the PanCan lung cancer risk prediction model.

OBJECTIVE: To report the long-term follow-up of subsolid nodules (SSNs) detected in participants of a prospective low-dose CT lung cancer screening cohort, and to investigate the utility of the PanCan model in stratifying risk in baseline SSNs. METHODS: Participants underwent a baseline scan, two annual incidence scans and further follow-up scans for the detected nodules. All SSNs underwent a minimum of 2 years of follow-up (unless resolved or resected). Risk of malignancy was estimated using the PanCan model; discrimination [area under the receiver-operating characteristic curve (AUC)] and calibration (Hosmer-Lemeshow goodness-of-fit test) were assessed. The Mann-Whitney U-Wilcoxon test was used to compare estimated risk between groups. RESULTS: 70 SSNs were detected in 41 (16.0%) out of 256 total participants. Median follow-up period was 25.5 months (range 2.0-74.0 months). 29 (41.4%) SSNs were transient. Five (7.1%) SSNs were resected, all found to be Stage I lung adenocarcinoma, including one SSN stable in size for 3.0 years before growth was detected. The PanCan model had good discrimination for the 52 baseline SSNs (AUC = 0.89; 95% confidence interval 0.76-1); the Hosmer-Lemeshow goodness-of-fit test was non-significant (p = 0.27). Estimated risk was significantly higher in the baseline SSNs found to be cancer vs those not found to be cancer after 2-6 years of follow-up (p < 0.01). CONCLUSION: Our findings support a long-term follow-up approach for screen-detected SSNs for 3 years or longer. The PanCan model appeared discriminatory and well calibrated in this cohort. ADVANCES IN KNOWLEDGE: The PanCan model may have utility in identifying low-risk SSNs which could be followed with less frequent CT scans.

Phenotypes and karyotypes of human malignant mesothelioma cell lines.

BACKGROUND: Malignant mesothelioma is an aggressive tumour of serosal surfaces most commonly pleura. Characterised cell lines represent a valuable tool to study the biology of mesothelioma. The aim of this study was to develop and biologically characterise six malignant mesothelioma cell lines to evaluate their potential as models of human malignant mesothelioma. METHODS: Five lines were initiated from pleural biopsies, and one from pleural effusion of patients with histologically proven malignant mesothelioma. Mesothelial origin was assessed by standard morphology, Transmission Electron Microscopy (TEM) and immunocytochemistry. Growth characteristics were assayed using population doubling times. Spectral karyotyping was performed to assess chromosomal abnormalities. Authentication of donor specific derivation was undertaken by DNA fingerprinting using a panel of SNPs. RESULTS: Most of cell lines exhibited spindle cell shape, with some retaining stellate shapes. At passage 2 to 6 all lines stained positively for calretinin and cytokeratin 19, and demonstrated capacity for anchorage-independent growth. At passage 4 to 16, doubling times ranged from 30-72 hours, and on spectral karyotyping all lines exhibited numerical chromosomal abnormalities ranging from 41 to 113. Monosomy of chromosomes 8, 14, 22 or 17 was observed in three lines. One line displayed four different karyotypes at passage 8, but only one karyotype at passage 42, and another displayed polyploidy at passage 40 which was not present at early passages. At passages 5-17, TEM showed characteristic features of mesothelioma ultrastructure in all lines including microvilli and tight intercellular junctions. CONCLUSION: These six cell lines exhibit varying cell morphology, a range of doubling times, and show diverse passage-dependent structural chromosomal changes observed in malignant tumours. However they retain characteristic immunocytochemical protein expression profiles of mesothelioma during maintenance in artificial culture systems. These characteristics support their potential as in vitro model systems for studying cellular, molecular and genetic aspects of mesothelioma.

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

BACKGROUND: The 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. METHODS: We 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. RESULTS: Based 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). CONCLUSION: Pleural 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.

Age, cumulative trauma and stressful life events, and post-traumatic stress symptoms among older adults in prison: do subjective impressions matter?

BACKGROUND: The aging prison population in the United States presents a significant public health challenge with high rates of trauma and mental health issues that the correctional system alone is ill-prepared to address. The purpose of this study was to examine the relationship of age, objective, and subjective measures of trauma and stressful life events and post-traumatic stress symptoms among older adults in prison. METHODS: Data were gathered from 334 prisoners (aged 55+) housed in the New Jersey Department of Corrections, as of September 2010. An anonymous self-report, self-administered survey was mailed to the total population of 1,000 prisoners aged 55 years and older. Objective and subjective trauma was measured using the Life Stressors Checklist-Revised (LSC-R), and post-traumatic stress symptoms were measured using the Civilian Version of the Post-traumatic Stress Scale. FINDINGS: Results of a path analysis revealed that past year subjective impressions of traumatic and stressful life events had a positive and significant relationship to current post-traumatic stress symptoms. Age was found to have a significant and inverse relationship to subjective traumatic and stressful life events. That is, younger participants reported higher levels of cumulative traumatic and stressful life events and past year subjective ratings of being bothered by these past events. IMPLICATIONS: These findings have significance for interdisciplinary/interprofessional practice and appropriate institutional and community care, including reentry planning of older adults in the criminal justice system.