Exhaled breath condensate is not suitable to detect EGFR somatic mutations

Concordance in molecular genetic analysis of tumour tissue, plasma, and exhaled breath condensate samples from lung cancer patients

AIM

Lung adenocarcinoma is characterized by poor prognosis and short survival rates. Therefore, tools to identify the tumoural molecular structure and guide effective diagnosis and therapy decisions are essential. Surgical biopsies are highly invasive and not conducive for patient follow-up. To better understand disease prognosis, novel non-invasive analytic methods are needed. The aim of the present study is to identify the genetic mutations in formalin-fixed paraffin-embedded (FFPE) tissue, plasma, and exhaled breath condensate (EBC) samples by next-generation sequencing and evaluate their utility in the diagnosis and follow-up of patients with lung adenocarcinoma.

METHOD

FFPE, plasma, and EBC samples were collected from 12 lung adenocarcinoma patients before treatment. DNA was extracted from the specimens using an Invitrogen PureLink Genomic DNA Kit according to the manufacturer's instructions. Amplicon-based sequencing was performed using Ion AmpliSeq Colon and Lung Cancer Research Panel v2.

RESULTS

Genetic alterations were detected in all FFPE, plasma, and EBC specimens. The mutations in PIK3CA, MET, PTEN, SMAD4, and FGFR2 genes were highly correlated in six patients. Somatic and novel mutations detected in tissue and EBC samples were highly correlated in one additional patient. The EGFR p.L858R and KRAS p.G12C driver mutations were found in both the FFPE tissue specimens and the corresponding EBC samples of the lung adenocarcinoma patients.

CONCLUSION

The driver mutations were detected in EBC samples from lung adenocarcinoma patients. The analysis of EBC samples represents a promising non-invasive method to detect mutations in lung cancer and guide diagnosis and follow-up.

[Progress in Non-invasive Detection of EGFR Mutation in Non-small Cell Lung Cancer]

在过去的十年里，癌症患者的管理模式已经逐渐转向为基于分子突变检测的个体化模式。表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变是非小细胞肺癌（non-small cell lung cancer, NSCLC）的重要驱动因素，针对EGFR的靶向治疗和传统化疗相比，显示出显著的安全性和有效性。然而，并不是所有的EGFR突变患者都可接受EGFR靶向治疗，不同的突变类型往往预示着不同的临床结局，如敏感性突变EGFR 19-Del、L858R和耐药性突变20ins。此外，如今已经开发出第三代TKI药物Osimertinib（AZD9291）和Rociletinib（CO-1686）可使因EGFR T790M突变，导致初代TKI耐药的患者进一步获益。因此，治疗前了解患者EGFR突变状态，治疗过程中持续监测耐药基因EGFR T790M突变情况，对NSCLC患者靶向药物的管理有着重要的意义。最近几年来，“液体活检”技术得到快速的发展，让我们看到采用非侵入性方法以实时监测耐药性突变成为现实的可能。在本综述中，我们回顾了NSCLC中检测EGFR突变的多种非侵入性检测技术在不同液体样本的临床应用。

Exhaled breath analysis for lung cancer detection using ion mobility spectrometry

BACKGROUND

Conventional methods for lung cancer detection including computed tomography (CT) and bronchoscopy are expensive and invasive. Thus, there is still a need for an optimal lung cancer detection technique.

METHODS

The exhaled breath of 50 patients with lung cancer histologically proven by bronchoscopic biopsy samples (32 adenocarcinomas, 10 squamous cell carcinomas, 8 small cell carcinomas), were analyzed using ion mobility spectrometry (IMS) and compared with 39 healthy volunteers. As a secondary assessment, we compared adenocarcinoma patients with and without epidermal growth factor receptor (EGFR) mutation.

RESULTS

A decision tree algorithm could separate patients with lung cancer including adenocarcinoma, squamous cell carcinoma and small cell carcinoma. One hundred-fifteen separated volatile organic compound (VOC) peaks were analyzed. Peak-2 noted as n-Dodecane using the IMS database was able to separate values with a sensitivity of 70.0% and a specificity of 89.7%. Incorporating a decision tree algorithm starting with n-Dodecane, a sensitivity of 76% and specificity of 100% was achieved. Comparing VOC peaks between adenocarcinoma and healthy subjects, n-Dodecane was able to separate values with a sensitivity of 81.3% and a specificity of 89.7%. Fourteen patients positive for EGFR mutation displayed a significantly higher n-Dodecane than for the 14 patients negative for EGFR (p<0.01), with a sensitivity of 85.7% and a specificity of 78.6%.

CONCLUSION

In this prospective study, VOC peak patterns using a decision tree algorithm were useful in the detection of lung cancer. Moreover, n-Dodecane analysis from adenocarcinoma patients might be useful to discriminate the EGFR mutation.

Molecular profiling of thin-prep FNA samples in assisting clinical management of non-small-cell lung cancer

The discovery of new target treatments for NSCLC has led to a search for new genetic and epigenetic markers able to selectively predict response to these new drugs. Somatic mutations in EGFR and KRAS genes are routinely analyzed to predict response to tyrosine kinase inhibitors (TKIs), used in the treatment of NSCLC patients, whose efficacy depend on the presence or the absence of specific mutations. MicroRNA (miRNA) expression evaluation has been recently analyzed because of the involvement of these molecules in lung cancer pathogenesis and in drug resistance. Only 30 % of NSCLC patients present a resectable stage at time of diagnosis so tissue samples cannot be the only starting material for genetic and epigenetic analysis. Therefore, the possibility to use cytological sampling already used for diagnosis also for molecular testing is emerging. The aim of this study was to evaluate for the first time in lung cancer the use of liquid-based cytology both for EGFR and KRAS mutational testing and for the expression trend of some miRNAs involved in lung cancer pathogenesis: miR-21, miR-155, miR-7, and let7a. We enrolled 20 fine-needle aspirate (FNA) samples diagnosed as NSCLC, 10 FNAs without neoplastic cells, and tissue samples coming from 5 of the 20 patients who underwent surgery after FNA NSCLC diagnosis. All Thin-Prep processed FNA samples were evaluable for DNA and RNA analysis and results were compared with those of the small group of patients whose matched tumor histology was available. The mutational status of the EGFR and KRAS genes and the expression profile of the selected miRNA showed comparable results between FNA samples and histological tissues. Our results underline that cytological samples could give the same genetic information as that obtained from histological specimens and so could be collected to create a nucleic acids bank.

Exhaled matrix metalloproteinase-9 in lung cancer

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) has been recognized in several types of tumor development and progression, including lung cancer, for its role in the degradation and remodeling of lung tissue. Furthermore, increased MMP-9 has been commonly described in the serum and airways of non-small cell lung cancer (NSCLC) patients.

OBJECTIVE

The aim of this study was to investigate, for the first time, MMP-9 in the exhaled breath condensate (EBC) of NSCLC patients.

PARTICIPANTS

We enrolled 40 NSCLC patients and 40 controls affected by transudative pleural effusion.

MEASUREMENTS

MMP-9 concentrations were measured in the EBC, whole blood (WB), and pleural effusion (PE) of all the subjects under study using enzyme immunoassay (EIA) kits.

RESULTS

MMP-9 levels were found to be significantly higher in EBC, WB, and PE of NSCLC patients compared with controls. A positive correlation was observed between MMP-9 in EBC, cigarettes smoked, and stage of cancer.

CONCLUSION

Exhaled MMP-9 was elevated in NSCLC patients, especially during tumor progression, and could represent a suitable noninvasive marker in the diagnosis and monitoring of lung cancer.

Microsatellite alterations and cell-free DNA analysis: could they increase the cytology sensitivity in the diagnosis of malignant pleural effusion?

BACKGROUND

The exact diagnosis of malignant pleural effusions (PE) is difficult and often requires combined procedures, because the cytological examination of pleural fluid does not detect tumoral cells in 40% of malignant effusion cases. The aim of this study was to analyze microsatellite alterations (MA) in malignant PE and to determine their diagnostic value as an additional test to cytological examination. The increase in cell-free DNA levels was also evaluated as a signal of probable malignancy.

METHODS

A total of 84 patients with PE were enrolled and underwent PE and whole blood and exhaled breath condensate analyses. Free DNA was measured by spectrophotometer analyses. DNA was extracted from all samples and analyzed for MA, using the microsatellite markers at chromosomes 3p, 12p, 5q, and 17p.

RESULTS

The microsatellite analysis of PE exhibited a higher percentage of alterations in malignant PE than in benign PE. In addition to this, cell-free DNA in PE was seen to be significantly more elevated in malignant than in benign PE. The sensitivity of the sole cytology increased considerably when patients showed at least one MA or DNA>4 ng/μL in the PE.

CONCLUSION

In conclusion, it was seen that the combination of the cytological examination with microsatellite analyses and cell-free DNA in pleural fluid could increase the sensitivity of the diagnosis in patients with PE who have a suspected malignancy, obviating the need for other invasive diagnostic procedures.

Detection of microorganisms in exhaled breath condensate during acute exacerbations of COPD

BACKGROUND AND OBJECTIVE

One hallmark of COPD is colonization and infection of the lung. Acute exacerbations of COPD (AECOPD) are acute deteriorations of the chronic disease and are associated with a change of the pulmonary microbial balance. The collection of exhaled breath condensate (EBC) can be used to non-invasively determine markers of lung disease. The aim of the present study was to compare the results of assays based on the detection of microbial nucleic acids from EBC and from spontaneous sputum in patients with AECOPD.

METHODS

EBC and sputa of 29 adults with AECOPD were obtained. Isolated DNA or RNA were used as starting material for the PCR assays to detect Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Legionella pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, influenza viruses (AH 1, AH 3) and respiratory syncytial virus.

RESULTS

Bacterial or viral nucleic acids were identified in 14 EBC and 21 sputa from 29 patients. Results from EBC did not correlate well with those from sputum. Viral and S. pneumoniae nucleic acids were detected only in sputum, whereas L. pneumophila DNA was only found in EBC. In three EBC and 10 sputa nucleic acids of more than one microorganism was detected.

CONCLUSIONS

Bacterial nucleic acids can be identified in EBC of COPD patients with exacerbations. The results obtained from EBC and sputum did not correlate well.

Detection of the EGFR mutation in exhaled breath condensate from a heavy smoker with squamous cell carcinoma of the lung

A 61-year-old male smoker (40 pack-years) presented with right chest pain. Computed tomography of the chest revealed a cavitary mass in the right lower lobe. A transbronchial biopsy showed squamous cell carcinoma. We examined epidermal growth factor receptor (EGFR) mutations in exhaled breath condensate (EBC). The DNA extracted from his EBC showed a deletion mutation in exon 19. Subsequently, the del E746-A750 mutation in exon 19 in a transbronchial tissue specimen was confirmed. Although he underwent whole-brain irradiation against multiple brain metastases, he had paralysis of the left side of the body and his performance status was 3. The patient was treated with gefitinib. He had marked tumor regression and no symptoms. Although only a small percentage of heavy smokers with squamous cell carcinoma harbor EGFR mutations, they probably benefit from EGFR-tyrosine kinase inhibitors. EGFR mutation status in the patients having such clinical features might be examined.