Detection of an EGFR mutation in cytological specimens of lung adenocarcinoma

Infection with human cytomegalovirus, Epstein-Barr virus, and high-risk types 16 and 18 of human papillomavirus in EGFR-mutated lung adenocarcinoma

AIM

To assess the frequency of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), and high-risk types of human papillomavirus (HPV16 and HPV18) infections in lung adenocarcinoma samples.

METHODS

Lung adenocarcinoma cytological smears and their DNA isolates were obtained from patients hospitalized at the Department for Lung Diseases Jordanovac, Zagreb, in 2016 and 2017. Overall, 67 lung adenocarcinoma samples were examined: 34 with epidermal growth factor receptor gene (EGFR) mutations and 33 without EGFR mutations. The EGFR mutation status and virus presence were assessed with a polymerase chain reaction, and random samples were additionally tested for EBV with Sanger sequencing. HCMV, EBV, HPV16, and HPV18 infections were evaluated in relation to EGFR mutation, smoking status, and sex. A meta-analysis of available data about HPV infection in non-small cell lung cancer was performed.

RESULTS

More frequent HCMV, EBV, HPV16, and HPV18 infections were observed in lung adenocarcinoma samples with EGFR mutations than in samples without these mutations. Coinfection of the investigated viruses was observed only in lung adenocarcinoma samples with mutated EGFR. In the group with EGFR mutations, smoking was significantly associated with HPV16 infection. The meta-analysis showed that non-small cell lung cancer patients with EGFR mutations had a higher odds of HPV infection.

CONCLUSION

HCMV, EBV, and high-risk HPV infections are more frequent in EGFR-mutated lung adenocarcinomas, which indicates a possible viral impact on the etiology of this lung cancer subtype.

Influence of deep-freezing and MGG staining on DNA and RNA quality in different types of lung adenocarcinoma cytological smears

BACKGROUND

Preserving the optimal quality of DNA and RNA is mandatory for molecular testing in lung adenocarcinoma cytological smears (LACSs).

METHODS

DNA and RNA were isolated from 90 frozen unstained and 46 May Grünwald Giemsa (MGG) stained LACSs prepared from bronchial washing (BW), bronchial brushing (BB), and pleural effusion (PE) samples during 3 years. Concentrations of nucleic acids in all LACSs were assessed by spectrophotometric analysis. Fragmentation of DNA and RNA was determined by PCR amplification of selected genes. Amplicons of 100, 200, 300, 400, and 600 bp were used for DNA and 108 bp-long HPRT1 transcript fragment for RNA fragmentation analysis.

RESULTS

Among 90 frozen LACSs, significantly lower DNA concentrations of BB and RNA concentrations of BW samples frozen for 6-10 months were observed in comparison with samples frozen for longer periods (p < .05). Among 46 paired LACSs, 44 (95.7%) frozen and 15 (32.6%) MGG-stained samples showed 600 bp-long DNA amplicons. Statistically significant difference (p < .05) in the fragmentation of DNA between frozen and MGG-stained LACSs was observed (p < .05), with DNA being less fragmented in frozen LACSs. In addition, 33 (71.7%) frozen and 36 (78.2%) MGG-stained LASCs showed HPRT1 gene amplicon of 108 bp. RNA was less fragmented in 3-year old MGG-stained samples than in LACSs frozen for 3 years.

CONCLUSION

DNA and RNA extracted from frozen and MGG-stained LACSs showed different results depending on the time of storage and/or type of samples, but in general all samples had adequate quantity and quality for downstream molecular testing.

Computed Tomography Imaging Characteristics: Potential Indicators of Epidermal Growth Factor Receptor Mutation in Lung Adenocarcinoma

PURPOSE

The purpose of this study was to investigate the correlation between computed tomography imaging characteristics in lung adenocarcinoma and epidermal growth factor receptor (EGFR) mutations.

METHODS

A total of 124 patients with lung adenocarcinoma and known EGFR mutation status were collected in this retrospective study. Computed tomography quantitative parameters of each tumor, including total volume, total surface, surface-to-volume ratio (SVR), average diameter, maximum diameter, and average density, were determined using computer-aided detection software. The correlation between the EGFR mutation status and imaging characteristics was assessed. The predictive value of these imaging characteristics for EGFR mutation was calculated using the area under the receiver operating characteristic curve.

RESULT

Fifty-eight of 124 patients showed EGFR mutations. Patients who are female (P < 0.001) and nonsmokers (P < 0.001) and those with serum carcinoembryonic antigen (CEA) level of ≥5 (P = 0.035) were likely to have EGFR mutation. Computed tomography features including air bronchogram (P = 0.035), absence of cavitation (P = 0.010), and absence of pulmonary emphysema (P = 0.002) and quantitative parameters, such as smaller total surface (P = 0.002), smaller total volume (P = 0.001), higher SVR (P = 0.003), and smaller average diameter (P = 0.001), were associated with EGFR mutation. Logistic regression analysis revealed that the most significant independent prognostic factors of EGFR mutation for the model were nonsmoking (P = 0.035), CEA level of ≥5 (P = 0.004), presence of air bronchogram (P = 0.040), absence of cavitation (P = 0.021), and high SVR (P = 0.014). The area under the receiver operating characteristic curve, sensitivity, and specificity of the model for predicting EGFR mutation were 0.827, 75.8%, and 82.8%, respectively.

CONCLUSIONS

EGFR-mutated adenocarcinoma showed significantly increased CEA level, presence of air bronchogram, absence of cavitation, and higher quantitative parameter SVR than those with wild-type EGFR.

EGFR Status Assessment for Better Care of Early Stage Non-Small Cell Lung Carcinoma: What Is Changing in the Daily Practice of Pathologists?

The recent emergence of novel neoadjuvant and/or adjuvant therapies for early stage (I-IIIA) non-small cell lung carcinoma (NSCLC), mainly tyrosine kinase inhibitors (TKIs) targeting EGFR mutations and immunotherapy or chemo-immunotherapy, has suddenly required the evaluation of biomarkers predictive of the efficacy of different treatments in these patients. Currently, the choice of one or another of these treatments mainly depends on the results of immunohistochemistry for PD-L1 and of the status of EGFR and ALK. This new development has led to the setup of different analyses for clinical and molecular pathology laboratories, which have had to rapidly integrate a number of new challenges into daily practice and to establish new organization for decision making. This review outlines the impact of the management of biological samples in laboratories and discusses perspectives for pathologists within the framework of EGFR TKIs in early stage NSCLC.

EGFR mutation detection of lung circulating tumor cells using a multifunctional microfluidic chip

Microfluidics has become a reliable platform for circulating tumor cells (CTCs) detection because of its high integration, small size, low consumption of reagents and rapid response. Here, we developed a multifunctional microfluidic device consists of three parts, including CTCs capture area, single-layer membrane valves area, and microcavity nucleic acid detection and analysis region based on digital polymerase chain reaction (dPCR), allowing CTCs capture, lysis, and genetic characterization to be performed on a single chip. The CTCs capture chip is coupled to the nucleic acid detection chip via a control valve. CTCs were firstly trapped in the CTC capture area, and then lysed using proteinase K to release nucleic acids. Subsequently CTCs lysate was transferred into nucleic acid detection area consisting of 12800 micro-cavity chambers for nucleic acids detection. To evaluate the performance of this chip, this study detected EGFR-L858R mutation in lung cancer cell lines H1975 and A549 cells, as well as leukocytes from normal donors. The results showed that positive signals were only observed in H1975 cells, and the detected value had a high linear relationship with the expected value (R² = 0.9897). In conclusion, this multi-functional microfluidic chip that integrates CTCs capture, lysis and nucleic acid detection can successfully detect gene mutations in CTCs, providing reference for tumor-targeted drugs and precise diagnosis and treatment.

Bronchial brushing cytology is comparable to bronchial biopsy for epidermal growth factor receptor mutation test in non-small cell lung cancer

Objectives:

Bronchial brushing (BB) is often used to obtain supplementary samples for diagnosing lung cancer. We examined the possibility of epidermal growth factor receptor (EGFR) testing on BB samples and compared them with bronchial biopsy samples.

Material and Methods:

We used 150 BB samples with non-small cell carcinoma submitted to our department within 2 years. Biopsy samples were concurrently submitted for histologic diagnosis. We used the peptide nucleic acid clamping method for EFGR mutation test. Histologic diagnosis identified 137 cases of adenocarcinomas and 13 cases of non-small cell lung carcinoma, not otherwise specified. Each sample was assessed for adequacy and DNA content for EGFR mutation test.

Results:

Among BB samples, 28 had exon 19 deletion, 21 had mutations in exon 21, 99 were wild type, and analysis of two failed. The EGFR mutation rate in BB samples was 33.1% (49/148). Among bronchial biopsy samples, 26 had exon 19 deletion, 20 had mutations in exon 21, 92 were wild type, and analysis of 12 failed. The EGFR mutation rate using biopsy sample was 33.8% (46/136). The mutation detection results were nearly identical in both groups of samples (131/138, 94.9%). However, in two cases, an exon 21 mZutation was detected in biopsy samples but not in BB samples. In five cases, exon 19 deletion (two cases) and exon 21 mutation (three cases) were detected in BB but not in biopsy samples. The median DNA content was 58.83 ng for BB samples and 48.47 ng for biopsy samples. The failure rate for BB samples was lower than for biopsy samples. Overall, the BB samples were comparable to bronchial biopsy samples in terms of DNA quantity and mutation detection results.

Conclusion:

We conclude that in case of inadequate biopsy samples, BB samples can be used as a substitute material for EGFR mutation test.

Comparison of Epidermal Growth Factor Receptor Gene Mutations Identified Using Pleural Effusion and Primary Tumor Tissue Samples in Non-Small Cell Lung Cancer

BACKGROUND

Although the use of pleural effusion samples for epidermal growth factor receptor (EGFR) testing in lung cancer is increasing, the accuracy rate and effectiveness of identifying EGFR mutations using these samples, rather than primary tumor tissue samples, is not established.

MATERIALS AND METHODS

One hundred ninety-two advanced, non-small cell lung cancer patients were enrolled into this study. All patients had primary tumor tissue and corresponding pleural effusion samples, and we employed the Amplification Refractory Mutation System to detect EGFR gene mutations in these samples.

RESULT

The number of EGFR mutations detected in primary tumor tissue and pleural effusion samples was 119 (61.98%) and 113 (58.85%), respectively. The EGFR-mutation rate was significantly higher in female than in male patients, and in adenocarcinoma than in nonadenocarcinoma patients (P=0.000). Single mutations in exons 19 and 21 were the predominant observed mutation type, and the overall concordance rate of EGFR-mutation status between the 192 matched pleural effusion and primary tumor tissue samples was 86.98%.

CONCLUSIONS

We observed a high concordance rate between EGFR mutations identified using primary tumor tissue and corresponding pleural effusion samples by Amplification Refractory Mutation System. Thus, it is likely that pleural effusion sampling from advanced non-small cell lung cancer patients, especially those with adenocarcinoma, may be effective in EGFR-mutation screening.

EGFR point mutation detection of single circulating tumor cells for lung cancer using a micro-well array

In view of their critical function in metastasis, characterization of single circulating tumor cells (CTCs) can provide important clinical information to monitor tumor progression and guide personal therapy. Single-cell genetic analysis methods based on microfluidics have some inherent shortcomings such as complicated operation, low throughput, and expensive equipment requirements. To overcome these barriers, we developed a simple and open micro-well array containing 26,208 units for either nuclear acids or single-cell genetic analysis. Through modification of the polydimethylsiloxane surface and optimization of chip packaging, we addressed protein adsorption and solution evaporation for PCR amplification on a chip. In the detection of epidermal growth factor receptor (EGFR) exon gene 21, this micro-well array demonstrated good linear correlation at a DNA concentration from 1 × 10¹ to 1 × 10⁵ copies/μL (R² = 0.9877). We then successfully integrated cell capture, lysis, PCR amplification, and signal read-out on the micro-well array, enabling the rapid and simple genetic analysis of single cells. This device was used to detect duplex EGFR mutation genes of lung cancer cell lines (H1975 and A549 cells) and normal leukocytes, demonstrating the ability to perform high-throughput, massively parallel duplex gene analysis at the single-cell level. Different types of point mutations (EGFR-L858R mutation or EGFR-T790M mutation) were detected in single H1975 cells, further validating the significance of single-cell level gene detection. In addition, this method showed a good performance in the heterogeneity detection of individual CTCs from lung cancer patients, required for micro-invasive cancer monitoring and treatment selection.

Sample types applied for molecular diagnosis of therapeutic management of advanced non-small cell lung cancer in the precision medicine

In this era of precision medicine, molecular biology is becoming increasingly significant for the diagnosis and therapeutic management of non-small cell lung cancer. The specimen as the primary element of the whole testing flow is particularly important for maintaining the accuracy of gene alteration testing. Presently, the main sample types applied in routine diagnosis are tissue and cytology biopsies. Liquid biopsies are considered as the most promising alternatives when tissue and cytology samples are not available. Each sample type possesses its own strengths and weaknesses, pertaining to the disparity of sampling, preparation and preservation procedures, the heterogeneity of inter- or intratumors, the tumor cellularity (percentage and number of tumor cells) of specimens, etc., and none of them can individually be a “one size to fit all”. Therefore, in this review, we summarized the strengths and weaknesses of different sample types that are widely used in clinical practice, offered solutions to reduce the negative impact of the samples and proposed an optimized strategy for choice of samples during the entire diagnostic course. We hope to provide valuable information to laboratories for choosing optimal clinical specimens to achieve comprehensive functional genomic landscapes and formulate individually tailored treatment plans for NSCLC patients that are in advanced stages.

Analysis of the frequency of EGFR, KRAS and ALK mutations in patients with lung adenocarcinoma in Croatia

Background

Many studies have been published on the mutational status of patients with lung adenocarcinomas, and great population-based variability in mutation frequencies has been reported. The main objective of the present study was to analyze the EGFR, KRAS and ALK mutation status in a representative cohort of patients in Croatia with lung adenocarcinomas and to correlate the mutational status with clinical data.

Methods

All patients who were newly diagnosed within 6 months with histologically proven primary lung adenocarcinomas were included. Mutational analyses for EGFR and KRAS mutations were performed in a cobas z 480 analyzer. ALK immunohistochemistry was performed using the D5F3 clone on Benchmark XT instrument. Clinical data were obtained from the medical records.

Results

Of the 324 patients, 59.9 % were male. At the time of diagnosis, the patients ranged in age range from 35 to 88 years (median 63 years). Most of the patients were current smokers or former smokers (77.2 %). EGFR mutations were found in 15.7 % of the patients, and of these mutations, exon 19 deletion was the most common (45.1 %). KRAS mutations were present in 34.9 % of the patients, while 4.1 % of patients were ALK-positive. The statistical significance of the presence of mutations was detected for both gender and smoking.

Conclusion

The detected mutation rates demonstrated a slightly higher prevalence of KRAS mutations, but not a higher prevalence of EGFR mutations or ALK gene rearrangement, in comparison with the rates found in other European countries. EGFR and ALK mutational status showed a statistically significant correlation with gender as well as with smoking, while KRAS mutation status showed a statistically significant correlation only with smoking.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-016-0544-9) contains supplementary material, which is available to authorized users.