Detection of EGFR mutations in liquid biopsy samples using allele-specific quantitative PCR: A comparative real-world evaluation of two popular diagnostic systems.

PURPOSE: The detection of epidermal growth factor receptor (EGFR) mutations in plasma cell-free DNA (cfDNA) is an auxiliary tool for the molecular diagnosis of non-small cell lung cancer (NSCLC), especially when an adequate tumor tissue specimen cannot be obtained. We compared the diagnostic accuracy of two commonly used in vitro diagnostic-certified allele-specific quantitative PCR assays for detecting plasma cfDNA EGFR mutations. METHODS: We analyzed EGFR mutations in plasma cfDNA from 90 NSCLC patients (stages I-IV) before treatment (n â€‹= â€‹60) and after clinical progression on EGFR tyrosine kinase inhibitors (n â€‹= â€‹30) using the cobas EGFR mutation test v2 (Roche Molecular Systems, Inc.) and therascreen EGFR Plasma RGQ PCR kit (Qiagen GmbH). RESULTS: There was higher concordance between plasma cfDNA and matched tumor tissue EGFR mutations with cobas (66.67%) compared with therascreen (55.93%). The concordance rate increased to 90.00% with cobas (Cohen's kappa coefficient, κ â€‹= â€‹0.80; p â€‹< â€‹0.0001) and 73.33% with therascreen (κ â€‹= â€‹0.49; p â€‹= â€‹0.0009) in advanced NSCLC patients. In treatment-naïve patients, cobas was superior to therascreen (sensitivity: 82.35% vs. 52.94%; specificity: 100% vs. 100%). In patients with clinical progression on EGFR tyrosine kinase inhibitors, EGFR exon 20 p.T790M was detected in 30% and 23% of cfDNA samples by cobas and therascreen, respectively. CONCLUSIONS: Cobas was superior to therascreen for detection of plasma EGFR mutations in advanced NSCLC. Plasma cfDNA EGFR mutation analysis is complex; therefore, the diagnostic accuracy of commercially available assays should be validated.

[A surprising diagnosis in a male with a tumour of the chest wall--not always lung cancer]. / Zaskakujace rozpoznanie u mezczyzny z guzem sciany klatki piersiowej--nie wszyscy choruja na raka pluca.

Lung cancer is the most frequent malignant tumour in men. Advanced disease may produce metastatic tumours in subcutaneous tissue and also infiltrate the chest wall. We present a history of a man referred to our department suspected of lung tumour infiltrating the chest wall. Additionally, bone metastatic disease was diagnosed (ribs, vertebral bodies and skull). Thanks to a wide diagnostic approach, ductal cancer of the breast was finally diagnosed, a neoplasm that is extremely rare in male patients, usually presenting as a definite nodule in the nipple area of the breast. This case shows the importance of careful histological evaluation of the chest wall tumour.

Quantitative analysis of free-circulating DNA in plasma of patients with resectable NSCLC.

OBJECTIVE: Minute amounts of free-circulating DNA are present in plasma of healthy individuals, whereas its increased concentration was observed in patients with malignant tumors including non-small cell lung cancer (NSCLC). This study aimed at demonstrating the potential usefulness of plasma DNA concentration monitoring in NSCLC patients for therapy effectiveness assessment throughout the treatment and follow-up period. METHODS: Plasma DNA concentration was assessed in 50 NSCLC patients (stage I - IIIA) prior and following the radical treatment using real-time quantitative PCR method. 10 orthopedic patient undergoing hip joint surgery and 40 healthy volunteers comprised control groups. RESULTS: NSCLC patients (8.02 ng/ml) demonstrated significantly higher mean plasma DNA concentration with respect to healthy controls (2.27 ng/ml; p < 0.0000). Drastic increase in plasma DNA levels up to mean 68.74 ng/ml was detected a week after primary tumor resection. Still, similar phenomenon was observed in patients subjected to orthopedic surgical treatment (from 3.00 to 28.38 ng/ml, p < 0.0015). Most resected NSCLC patients with no disease recurrence during 3- to 6-month follow-up demonstrated reduced plasma DNA levels (mean 2.77 ng/ml) with respect to their presurgical values, whereas in relapsed subjects plasma DNA levels were significant higher. CONCLUSION: Free-circulating DNA concentration in plasma was significantly higher in NSCLC patients versus healthy controls. Its drastic increase following radical NSCLC treatment was most likely due to the surgical trauma. Importantly, the kinetics of plasma free-circulating DNA seems to be a promising marker of long-term effects of radical surgery in NSCLC.

[Simultaneous detection of tumor cells and the positive result of genetic test for Mycobacterium tuberculosis in pleural effusion]. / Jednoczesne wykrycie komórek nowotworowych i materialu genetycznego pratków gruzlicy w plynie oplucnowym.

Pleural effusion is a frequently observed lesion in the course of respiratory diseases such as inflammatory process and cancer metastasis. Its cause may be either tuberculosis (the most common extrapulmonary location is the pleura) and malignant disease of the pleura. Confirmation of tuberculosis is often troublesome. The primary site of cancer may be also difficult to find despite the application of difficult diagnostic methods. Below we present history of 79-year-old female in whom carcinomatous cells and positive result of PCR for Mycobacterium tuberculosis in pleural fluid were discovered simultaneously suggesting the tuberculosis and cancer of unknown primary origin.

[Diagnostic difficulties in primary mesothelioma]. / Trudnosci diagnostyczne w rozpoznawaniu pierwotnego zlosliwego miedzybloniaka osierdzia.

A 54-year-old woman with a history of fatigue and shortness of breath was found to have a pericardial effusion and mild mediastinal lymphadenopathy. Video-assisted pericardioscopy revealed thickened pericardium studded with multiple nodules. Histologically the tumor was diagnosed as papillary adenocarcinoma. The site of the primary tumor could not be identified. As lung cancer is one of the most frequent causes of pericardial metastases the patient was treated with cisplatin and vinblastin. Following 5 courses of chemotherapy--given over a 4 month period--the amount of pericardial effusion and pericardial thickness did not change. The material from pericardial biopsy was reexamined and positive immunostaining for calretinine was found. The final diagnosis was primary pericardial mesothelioma of epithelioid type. Palliative radiotherapy of mediastinum was planned but the patient deteriorated and died due to disease progression with venous thrombosis and superior vena cava syndrome. The case illustrates the difficulties in establishing diagnosis of primary pericardial mesothelioma which is a rare tumor with poor prognosis.