ARMS for EGFR mutation analysis of cytologic and corresponding lung adenocarcinoma histologic specimens

Advances in novel strategies for isolation, characterization, and analysis of CTCs and ctDNA

Over the past decade, the detection and analysis of liquid biopsy biomarkers such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have advanced significantly. They have received recognition for their clinical usefulness in detecting cancer at an early stage, monitoring disease, and evaluating treatment response. The emergence of liquid biopsy has been a helpful development, as it offers a minimally invasive, rapid, real-time monitoring, and possible alternative to traditional tissue biopsies. In resource-limited settings, the ideal platform for liquid biopsy should not only extract more CTCs or ctDNA from a minimal sample volume but also accurately represent the molecular heterogeneity of the patient's disease. This review covers novel strategies and advancements in CTC and ctDNA-based liquid biopsy platforms, including microfluidic applications and comprehensive analysis of molecular complexity. We discuss these systems' operational principles and performance efficiencies, as well as future opportunities and challenges for their implementation in clinical settings. In addition, we emphasize the importance of integrated platforms that incorporate machine learning and artificial intelligence in accurate liquid biopsy detection systems, which can greatly improve cancer management and enable precision diagnostics.

Ultra-rapid Idylla™ EGFR mutation screening followed by next-generation sequencing: An integrated solution to molecular diagnosis of non-small cell lung cancer

Background

Rapid profiling of the EGFR mutations is crucial to help clinicians choose the optimal treatment for patients with advanced/metastatic Non-Small Cell Lung Cancer (NSCLC). Unfortunately, current diagnostic techniques, including ARMS-PCR and NGS, generally require several days to deliver final results. This diagnostic delay may lead to treatment delays for patients who are worsening rapidly.

Methods

This study introduced the ultra-rapid Idylla™ system for rapid, sensitive and specific identification of the EGFR mutations among Chinese NSCLC patients. Idylla™ EGFR Assay, an integrated cartridge running on the Idylla™ system, which can detect 51 EGFR mutations directly from Formalin-Fixed, Paraffin-Embedded (FFPE) samples within 2.5 hours, was used in this study. The sensitivity and specificity of the Idylla™ system were evaluated in comparison with ARMS-PCR or NGS using 95 clinical samples.

Results

The Idylla™ system achieved a sensitivity of 97.6%, a specificity of 100%, and an overall concordance of 97.9% for 95 retrospective samples. When compared to ARMS-PCR, the Idylla™ system demonstrated high accuracy with an overall agreement of 97.1% (34/35), a sensitivity of 95.2% (20/21) (95% CI, 76.2% - 99.9%), and an estimated specificity of 100% (12/12) (95% CI, 76.8% - 100%) for 35 prospective samples.

Conclusions

This Idylla system provides a rapid, accurate and simple approach for screening EGFR mutations, which can guide Tyrosine Kinase Inhibitors (TKI) treatment for NSCLC patients in a timely manner.

Concordance of Cytological Specimens with Histological Tissue for Detection of Epidermal Growth Factor Receptor Mutation in Non-Small Cell Lung Cancer: A Systematic Review

INTRODUCTION

There is increasing need for more testing in non-small cell lung cancer given the introduction of newer targeted therapies. Cytological specimens including conventional smears (CS), cell blocks (CB), and liquid-based cytology (LBC) are an alternative to histologic tissue (HT) specimens in detecting EGFR mutations, but the concordance of these 2 specimens is yet to be determined. The aim of the present systematic review is to determine the concordance rates between different cytologic specimens with HT in detecting EGFR mutations.

METHODS

PubMed, Cochrane Library, and Google Scholar were utilized in the primary search, along with reference lists of electronically retrieved full-text articles. Concordance rates were pooled together if 2 or more studies reporting the same type of cytologic specimen were available.

RESULTS

Overall, 15 studies were included in this review, with 13 studies included in the pooled analysis. There was an overall concordance rate of 92.8% in 593 paired cytologic and HT specimens, with LBC having the highest concordance rate of 96.0%, followed by CS and CB, each with a concordance rate of 95.8%, although the concordance rate of CS and/or CB was lower at 90.6% with a larger pool of studies. LBC was found to have a significantly higher concordance rate than CS and/or CB.

CONCLUSION

Cytological specimens have a high concordance rate in detecting EGFR mutations, when compared to HT. LBC has shown superior concordance rates compared to CS and CB. Cytological specimens should be considered as an additional and alternative source of diagnostic material for EGFR testing.

Comprehensive analysis of NGS and ARMS-PCR for detecting EGFR mutations based on 4467 cases of NSCLC patients

BACKGROUND

By comparing the detection rate and type of targeted gene mutations in non-small cell lung cancer (NSCLC) between amplification refractory mutation system PCR (ARMS-PCR) and next-generation sequencing (NGS), the characteristics and application advantages of non-small cell lung cancer detection are explained, providing a basis for clinicians to effectively select the corresponding detection methods.

METHODS AND MATERIALS

The cases of targeted genes for lung cancer were selected from the First Affiliated Hospital of Chongqing Medical University from January 2016 to October 2020. A sample of 4467 cases was selected, and they were diagnosed with NSCLC by Pathological biopsy. Sample sources include surgical resection, bronchoscope biopsy, metastatic biopsy, blood, sputum, cytology of pleural effusion. Among them, 3665 cases were detected by ARMS-PCR technique, and 802 cases were detected by NGS technology. The detection rate and type of ARMS-PCR and NGS techniques for EGFR gene mutations (including exon 18, exon 19, exon 20, exon 21 and so on) in different NSCLC samples were compared, respectively.

RESULTS

The total mutation rate of EGFR gene detected by ARMS-PCR was 47.6% while 42.4% detected by NGS which indicated that there was a significant difference between the two methods in detecting total mutation of EGFR gene (P < 0.001). In different exons, the EGFR mutation rate detected by two methods is various. The mutation rate of exon 19 by ARMS-PCR detection was evidently higher than that of NGS detection, while the mutation rate of exons 20 and 21 by ARMS-PCR detection were statistically significantly lower than that of NGS detection. Moreover, the multiple mutation rate detected by NGS was 16.3% which was much higher than the 2.7% detected by ARMS-PCR with statistically different.

CONCLUSION

It showed that NGS could direct the drug use for the resistant patients. However, some rare loci could be detected by NGS but the importance and directed meaning are still unknown and the number of rare mutations is rare too. Further research on new biomarkers and technique is still needed for early diagnosis, directing drug use and assessing the therapy prognosis.

EGFR mutations subset in Chinese lung squamous cell carcinoma patients

Research has identified that epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) possess large benefits for adenocarcinoma (ADC), although little benefit for squamous cell carcinoma (SCC). The aim of the present study was to investigate the percentage of patients with SCC with the EGFR mutations subset and the benefits of EGFR TKIs in SCC. In the present study, the EGFR mutations subset was detected with an amplification refractory mutation system in 1,359 clinical SCC tissues. The association of the EGFR mutations subset with clinicopathological parameters was evaluated using the Mann-Whitney U test, and Kruskal-Wallis H. Kaplan-Meier survival analysis was used to estimate the effect of the EGFR mutations subset on SCC patient survival rates. A total of 94 out of 1,359 SCC patients were identified as having EGFR mutations, an EGFR mutation rate of 6.92%. The EGFR mutations subset in the 94 cases was identified as follows: 37.2% (35/94) in exon 19; 39.4% (37/94) in L858R; 5.3% (5/94) in T790M; 4.3% (4/94) in G719X; 2.1% (2/94) in L861Q; and 11.7% (11/94) in other mutations. Kaplan-Meier survival analysis identified that the differentiation, pathological tumor, node, metastasis stage, lymph node metastasis and distant metastases were significantly associated with patients' survival (P>0.05; log-rank test), and no significant difference was observed between TKI therapy and chemotherapy in terms of patient survival rates (P>0.05). In addition, the overall discordant rate of the EGFR mutations subset in SCC patients was relatively low. Due to the non-significant difference between TKI therapy and chemotherapy in terms of patient survival and the lower discordance rate of the EGFR mutations subset in SCC patients, EGFR TKIs could be a recommended treatment for SCC.

Mixed Responses to Systemic Therapy Revealed Potential Genetic Heterogeneity and Poor Survival in Patients with Non-Small Cell Lung Cancer

BACKGROUND

A subset of patients with non-small cell lung cancer (NSCLC) fosters mixed responses (MRs) to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) or chemotherapy. However, little is known about the clinical and molecular features or the prognostic significance and potential mechanisms.

METHODS

The records of 246 consecutive patients with NSCLC receiving single-line chemotherapy or TKI treatment and who were assessed by baseline and interim positron emission tomography/computed tomography scans were collected retrospectively. The clinicopathological correlations of the MR were analyzed, and a multivariate analysis was performed to explore the prognostic significance of MR.

RESULTS

The overall incidence of MR to systemic therapy was 21.5% (53/246) and predominated in patients with stage IIIB-IV, EGFR mutations and those who received TKI therapy (p < .05). Subgroup analyses based on MR classification (efficacious versus inefficacious) showed significant differences in subsequent treatment between the two groups (p < .001) and preferable progression-free survival (PFS) and overall survival (OS) in the efficacious MR group. Multivariate analyses demonstrated that the presence of MR was an independent unfavorable prognostic factor for PFS (hazard ratio [HR], 1.474; 95% confidence interval [CI], 1.018-2.134; p = .040) and OS (HR, 1.849; 95% CI, 1.190-2.871; p = .006) in patients with NSCLC. Induced by former systemic therapy, there were more T790M (18%), concomitant EGFR mutations (15%), and changes to EGFR wild type (19%) in the MR group among patients with EGFR mutations, which indicated higher incidence of genetic heterogeneity.

CONCLUSION

MR was not a rare event in patients with NSCLC and tended to occur in those with advanced lung adenocarcinoma treated with a TKI. MR may result from genetic heterogeneity and is an unfavorable prognostic factor for survival. Further studies are imperative to explore subsequent treatment strategies. The Oncologist 2017;22:61-69Implications for Practice: Tumor heterogeneity tends to produce mixed responses (MR) to systemic therapy, including TKI and chemotherapy; however, the clinical significance and potential mechanisms are not fully understood, and the subsequent treatment after MR is also a clinical concern. The present study systemically assessed patients by PET/CT and differentiated MR and therapies. The study identified a relatively high incidence of MR in patients with advanced NSCLC, particularly those treated with targeted therapies. An MR may be an unfavorable prognostic factor and originate from genetic heterogeneity. Further studies are imperative to explore subsequent treatment strategies.

Detection of Rare Mutations in EGFR-ARMS-PCR-Negative Lung Adenocarcinoma by Sanger Sequencing

PURPOSE

This study aimed to identify potential epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer that went undetected by amplification refractory mutation system-Scorpion real-time PCR (ARMS-PCR).

MATERIALS AND METHODS

A total of 200 specimens were obtained from the First Affiliated Hospital of Guangzhou Medical University from August 2014 to August 2015. In total, 100 ARMS-negative and 100 ARMS-positive specimens were evaluated for EGFR gene mutations by Sanger sequencing. The methodology and sensitivity of each method and the outcomes of EGFR-tyrosine kinase inhibitor (TKI) therapy were analyzed.

RESULTS

Among the 100 ARMS-PCR-positive samples, 90 were positive by Sanger sequencing, while 10 cases were considered negative, because the mutation abundance was less than 10%. Among the 100 negative cases, three were positive for a rare EGFR mutation by Sanger sequencing. In the curative effect analysis of EGFR-TKIs, the progression-free survival (PFS) analysis based on ARMS and Sanger sequencing results showed no difference. However, the PFS of patients with a high abundance of EGFR mutation was 12.4 months [95% confidence interval (CI), 11.6-12.4 months], which was significantly higher than that of patients with a low abundance of mutations detected by Sanger sequencing (95% CI, 10.7-11.3 months) (p<0.001).

CONCLUSION

The ARMS method demonstrated higher sensitivity than Sanger sequencing, but was prone to missing mutations due to primer design. Sanger sequencing was able to detect rare EGFR mutations and deemed applicable for confirming EGFR status. A clinical trial evaluating the efficacy of EGFR-TKIs in patients with rare EGFR mutations is needed.

Malignant pleural effusions because of lung cancer

PURPOSE OF REVIEW

The discovery of a pleural effusion in the setting of lung cancer has diagnostic, prognostic, and therapeutic challenges, some of which are addressed in this review.

RECENT FINDINGS

Around 20% of patients with lung cancer have minimal pleural effusions, which are not amenable to a diagnostic thoracentesis. These patients have a poorer overall survival (∼7.5 months) than those without effusions (∼12-18 months), although slightly better than those with proven malignant fluids (∼5.5 months). Tumor genotype techniques are feasible on pleural fluid specimens and clinically helpful in identifying patients who may benefit from targeted therapies. If limited pleural involvement is detected during lung cancer surgery despite the presurgical imaging studies, macroscopic complete resection of the lung tumor is still a treatment option. Cytological examination for cancer cells in pleural cavity washings at the time of thoracotomy (pleural lavage cytology) is recommended to uncover pleural dissemination. Patients with non-small cell lung cancer with visceral pleural invasion might be considered candidates for postsurgical adjuvant therapy.

SUMMARY

Some predictors of adverse survival in patients with lung cancer include the presence of a minimal pleural effusion, positive pleural lavage cytology, visceral pleural invasion on pathologic examination, and unexpected pleural involvement during surgery.

Effect of multiple cycles of freeze-thawing on the RNA quality of lung cancer tissues

RNA degradation is a major problem in tissue banking. We explored the effect of thawing flash-frozen biospecimens on the quality and integrity of RNA for genetic testing as well as for other cancer research studies. The histological quality of the frozen tumor sections was evaluated by using hematoxylin and eosin staining. RNA extraction from 60 lung cancer tissue samples subjected to various freeze/thaw cycles was performed using the RNeasy Plus isolation kit. RNA integrity was assessed by using an Agilent bioanalyzer to obtain RNA integrity numbers (RIN). Furthermore, RNA from different groups was used for fluorescence Reverse transcription-polymerase chain reaction (RT-PCR) analysis of the echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (EML4-ALK) fusion gene mutation to verify whether it can be used for research or clinical testing. Highly variable RIN values were observed among the samples, which showed no correlation with the number of freeze/thaw cycles conducted. However, after 3 freeze/thaw cycles (each thaw event lasted for 10 min), an increasing number of changes in peak intensity in RINs were observed. After 5 freeze/thaw cycles, RNA integrity decreased to approximately 35%. After 3 freeze/thaw cycles, the RNA could still be used for RT-PCR analysis of EML4-ALK fusion gene mutations; whereas those subjected to 5 freeze/thaw cycles could not. Limited (<3) freeze/thaw cycles did not adversely affect the quality of RNA extracted from tumor tissues and subsequent RT-PCR analysis. Our data could be utilized in the establishment of a standardized procedure for tissue biospecimen collection and storage.

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.

EGFR mutations in non-small cell lung cancer: an audit from West China Hospital

OBJECTIVES

To discover the incidence and characteristics of EGFR mutations in non-small cell lung cancer (NSCLC) in a single, large cohort as a part of routine diagnostic investigations.

METHODS

We reviewed EGFR mutations investigated by Amplification Refractory Mutation System (ARMS) PCR (covering 29 known mutations) using DNA samples from FFPE tissue or cell clot specimens in a total of 3894 cases of NSCLC analysed between 2012-2014.

RESULTS

EGFR mutations are preferentially associated with adenocarcinomaand adenosquamous histology, particularly those well to moderately differentiated, and were significantly more common in female than male patients irrespective of histological subtypes. Exon 19 deletion (45.7%) and exon 21 L858R (45.6%) accounted for the vast majority of the EGFR mutations detected, with the remaining mutations being infrequent (<2%). Compound mutations were seen in 51 (3%) of the mutant cases, the combination of these compound mutations could be classified into three subgroups according to the potential impact of individual mutations on EGFR TKI therapy. Accordingly, 7 cases had both sensitive mutations, 4 cases harboured one sensitive and one less responsive /uncertain mutation, 19 cases contained one sensitive and one resistant change, and a further 21 cases had two less responsive /uncertain mutations.

CONCLUSION

Our data represents the largest EGFR mutation survey based on routine clinical diagnostic laboratory data from a single institution, it confirms the incidence and characteristics of EGFR mutations in NSCLC seen in Asian patients, and also unravels the combinatorial nature of rare compound EGFR mutations.

Detection of EML4-ALK fusion gene and features associated with EGFR mutations in Chinese patients with non-small-cell lung cancer

PURPOSE

Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) and epidermal growth factor receptor (EGFR) define specific molecular subsets of lung cancer with distinct clinical features. We aimed at revealing the clinical features of EML4-ALK fusion gene and EGFR mutation in non-small-cell lung cancer (NSCLC).

METHODS

We enrolled 694 Chinese patients with NSCLC for analysis. EML4-ALK fusion gene was analyzed by real-time polymerase chain reaction, and EGFR mutations were analyzed by amplified refractory mutation system.

RESULTS

Among the 694 patients, 60 (8.65%) patients had EML4-ALK fusions. In continuity correction χ (2) test analysis, EML4-ALK fusion gene was correlated with sex, age, smoking status, and histology, but no significant association was observed between EML4-ALK fusion gene and clinical stage. A total of 147 (21.18%) patients had EGFR mutations. In concordance with previous reports, EGFR mutation was correlated with age, smoking status, histology, and clinical stage, whereas patient age was not significantly associated with EGFR mutation. Meanwhile, to our surprise, six (0.86%) patients had coexisting EML4-ALK fusions and EGFR mutations.

CONCLUSION

EML4-ALK fusion gene defines a new molecular subset in patients with NSCLC. Six patients who harbored both EML4-ALK fusion genes and EGFR mutations were identified in our study. The EGFR mutations and the EML4-ALK fusion genes are coexistent.

CT Features Associated with Epidermal Growth Factor Receptor Mutation Status in Patients with Lung Adenocarcinoma

Purpose To retrospectively identify the relationship between epidermal growth factor receptor (EGFR) mutation status, predominant histologic subtype, and computed tomographic (CT) characteristics in surgically resected lung adenocarcinomas in a cohort of Asian patients. materials and Methods This study was approved by the institutional review board, with waiver of informed consent. Preoperative chest CT findings were retrospectively evaluated in 385 surgically resected lung adenocarcinomas. A total of 30 CT descriptors were assessed. EGFR mutations at exons 18-21 were determined by using the amplification refractory mutation system. Multiple logistic regression analyses were performed to identify independent factors of harboring EGFR mutation status. The final model was selected by using the backward elimination method, and two areas under the receiver operating characteristic curve (ROC) were compared with the nonparametric approach of DeLong, DeLong, and Clarke-Pearson. Results EGFR mutations were found in 168 (43.6%) of 385 patients. Mutations were found more frequently in (a) female patients (P < .001); (b)those who had never smoked (P < .001); (c)those with lepidic predominant adenocarcinomas (P = .001) or intermediate pathologic grade (P < .001); (e) smaller tumors (P < .001); (f)tumors with spiculation (P = .019), ground-glass opacity (GGO) or mixed GGO (P < .001), air bronchogram (P = .006), bubblelike lucency (P < .001), vascular convergence (P = .024), thickened adjacent bronchovascular bundles (P = .027), or pleural retraction (P < .001); and (g) tumors without pleural attachment (P = .004), a well-defined margin (P = .010), marked heterogeneous enhancement (P = .001), severe peripheral emphysema (P = .002), severe peripheral fibrosis (P = .013), or lymphadenopathy (P = .028). The most important and significantly independent prognostic factors of harboring EGFR-activating mutation for the model with both clinical variables and CT features were those who had never smoked and those with smaller tumors, bubblelike lucency, homogeneous enhancement, or pleural retraction when adjusting for histologic subtype, pathologic grade, or thickened adjacent bronchovascular bundles. ROC curve analysis showed that use of clinical variables combined with CT features (area under the ROC curve = 0.778) was superior to use of clinical variables alone (area under the ROC curve = 0.690). Conclusion CT imaging features of lung adenocarcinomas in combination with clinical variables can be used to prognosticate EGFR mutation status better than use of clinical variables alone. (©) RSNA, 2016 Online supplemental material is available for this article.

Analysis of Mutations in Epidermal Growth Factor Receptor Gene in Korean Patients with Non-small Cell Lung Cancer: Summary of a Nationwide Survey

Background:

Analysis of mutations in the epidermal growth factor receptor gene (EGFR) is important for predicting response to EGFR tyrosine kinase inhibitors. The overall rate of EGFR mutations in Korean patients is variable. To obtain comprehensive data on the status of EGFR mutations in Korean patients with lung cancer, the Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists initiated a nationwide survey.

Methods:

We obtained 1,753 reports on EGFR mutations in patients with lung cancer from 15 hospitals between January and December 2009. We compared EGFR mutations with patient age, sex, history of smoking, histologic diagnosis, specimen type, procurement site, tumor cell dissection, and laboratory status.

Results:

The overall EGFR mutation rate was 34.3% in patients with non-small cell lung cancer (NSCLC) and 43.3% in patients with adenocarcinoma. EGFR mutation rate was significantly higher in women, never smokers, patients with adenocarcinoma, and patients who had undergone excisional biopsy. EGFR mutation rates did not differ with respect to patient age or procurement site among patients with NSCLC.

Conclusions

EGFR mutation rates and statuses were similar to those in published data from other East Asian countries.