Coexistence of EGFR with KRAS, or BRAF, or PIK3CA somatic mutations in lung cancer: a comprehensive mutation profiling from 5125 Chinese cohorts

The Presence of Concomitant Mutations Affects the Activity of EGFR Tyrosine Kinase Inhibitors in EGFR-Mutant Non-Small Cell Lung Cancer (NSCLC) Patients

Recent findings suggest that a fraction of EGFR-mutant non-small-cell lung cancers (NSCLC) carry additional driver mutations that could potentially affect the activity of EGFR tyrosine kinase inhibitors (TKIs). We investigated the role of concomitant KRAS, NRAS, BRAF, PIK3CA, MET and ERBB2 mutations (other mutations) on the outcome of 133 EGFR mutant patients, who received first-line therapy with EGFR TKIs between June 2008 and December 2014. Analysis of genomic DNA by Next Generation Sequencing (NGS) revealed the presence of hotspot mutations in genes other than the EGFR, including KRAS, NRAS, BRAF, ERBB2, PIK3CA, or MET, in 29/133 cases (21.8%). A p.T790M mutation was found in 9/133 tumour samples (6.8%). The progression free survival (PFS) of patients without other mutations was 11.3 months vs. 7 months in patients with other mutations (log-rank test univariate: p = 0.047). In a multivariate Cox regression model including the presence of other mutations, age, performance status, smoking status, and the presence of p.T790M mutations, the presence of other mutations was the only factor significantly associated with PFS (Hazard Ratio 1.63, 95% CI 1.04⁻2.58; p = 0.035). In contrast, no correlation was found between TP53 mutations and patients' outcome. These data suggest that a subgroup of EGFR mutant tumours have concomitant driver mutations that might affect the activity of first-line EGFR TKIs.

The Value of Liquid Biopsies for Guiding Therapy Decisions in Non-small Cell Lung Cancer

Targeted therapies have allowed for an individualized treatment approach in non-small-cell lung cancer (NSCLC). The initial therapeutic decisions and success of targeted therapy depend on genetic identification of personal tumor profiles. Tissue biopsy is the gold standard for molecular analysis, but non-invasive or minimally invasive liquid biopsy methods are also now used in clinical practice, allowing for later monitoring and optimization of the cancer treatment. The inclusion of liquid biopsy in the management of NSCLC provides strong evidence on early treatment response, which becomes a basis for determining disease progression and the need for changes in treatment. Liquid biopsies can drive the decision making for treatment strategies to achieve better patient outcomes. Cell-free DNA and circulating tumor cells obtained from the blood are promising markers for determining patient status. They may improve cancer treatments, allow for better treatment control, enable early interventions, and change decision making from reactive actions toward more predictive early interventions. This review aimed to present current knowledge on and the usefulness of liquid biopsy studies in NSCLC from the perspective of how it has allowed individualized treatments according to gene profiling and how the method may alter the treatment decisions in the future.

Application of amplicon-based targeted sequencing with the molecular barcoding system to detect uncommon minor EGFR mutations in patients with treatment-naïve lung adenocarcinoma

Background

In lung cancer, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor sensitizing mutations co-existing with rare minor EGFR mutations are known as compound mutations. These minor EGFR mutations can lead to acquired resistance after EGFR tyrosine kinase inhibitor treatment, so determining the mutation status of patients is important. However, using amplicon-based targeted deep sequencing based on next-generation sequencing to characterize mutations is prone to sequencing error. We therefore assessed the benefit of incorporating molecular barcoding with high-throughput sequencing to investigate genomic heterogeneity in treatment-naïve patients who have undergone resection of their non-small cell lung cancer (NSCLC) EGFR mutations.

Methods

We performed amplicon-based targeted sequencing with the molecular barcoding system (MBS) to detect major common EGFR mutations and uncommon minor mutations at a 0.5% allele frequency in fresh–frozen lung cancer samples.

Results

Profiles of the common mutations of EGFR identified by MBS corresponded with the results of clinical testing in 63 (98.4%) out of 64 cases. Uncommon mutations of EGFR were detected in seven cases (10.9%). Among the three types of major EGFR mutations, patients with the G719X mutation had a significantly higher incidence of compound mutations than those with the L858R mutation or exon 19 deletion (p = 0.0052). This was validated in an independent cohort from the Cancer Genome Atlas dataset (p = 0.018).

Conclusions

Our findings demonstrate the feasibility of using the MBS to establish an accurate NSCLC patient genotype. This work will help understand the molecular basis of EGFR compound mutations in NSCLC, and could aid the development of new treatment modalities.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5374-1) contains supplementary material, which is available to authorized users.

The clinical value of circulating tumor DNA detection in advanced non-small cell lung cancer

Background

Circulating tumor DNA (ctDNA) is a kind of cell-free DNA which comes from tumor cells and effectively reflects the molecular characteristics of tumors, which providing us a novel method to explore its clinical therapeutic value in advanced lung cancer.

Methods

A total of 36 patients with advanced non-small cell lung cancer (NSCLC) were enrolled in this study, including 28 cases of adenocarcinoma and 8 cases of squamous cell carcinoma. Next-generation sequencing based ctDNA detection, tissue DNA (tDNA) detection, corresponding survival analysis, and retrospective statistics were performed to explore the feasibility of clinical practice directed by molecular characteristics in NSCLC.

Results

Epidermal growth factor receptor mutation (EGFR mutation) took over the highest mutation frequency (36.11%) in 36 samples, and the subsequent genes were PIK3CA, BRAF, KRAS, NRAS, MAP2K1, and GNAQ; 11 patients were detected with multiple gene mutations, including 8 cases with double gene mutations, 1 case with three gene mutations, and 2 cases with four gene mutations, and the subsequent 12-month survival observation revealed that patients with less mutations also had a longer OS (10.37±0.74 vs. 7.08±1.43 months, P=0.034). Twenty-one patients with EGFR mutation and subsequently treated with EGFR-tyrosine kinase inhibitor (TKI) combined chemotherapy, had significantly longer PFS than those with EGFR wild type and treated with chemotherapy in next 5-year monitoring test (18.00±4.41 vs. 7.33±1.58 months, P=0.024).

Conclusions

Gene mutation in advanced lung cancer is complex, and ctDNA detection has important guiding significance in clinical treatment of advanced NSCLC.

Advanced Non-Small Cell Lung Cancer with Activating Epidermal Growth Factor Receptor Mutation: First Line Treatment and Beyond

BACKGROUND

Lung cancer is the leading cause of cancer mortality, being responsible for more than 1.6 million deaths each year worldwide and non-small-cell lung cancer (NSCLC) accounts for approximately 85% of lung cancers; moreover, 10 to 15% of all NSCLCs harbor EGFR (epidermal growth factor receptor) activating mutations, being suitable for EGFR-Tyrosine Kinase Inhibitors (TKI) molecular targeted therapy. However, EGFR+ NSCLCs gain acquired resistance to these agents, representing one of the key challenges for modern precision oncology.

OBJECTIVE

Therefore, this paper aims to provide an extensive state of the art review, alongside with hints about future perspectives.

CONCLUSION

To date, in the light of the data from the FLAURA study, osimertinib represents the best first-line option in NSCLC patients with EGFR activating mutations; EGFR-TKI plus chemotherapy combination therapies, even though interesting, must still be considered investigational.

Clinical validation of coexisting driver mutations in colorectal cancers

Mutational profiling is recommended for selecting targeted therapy and predicting prognosis of metastatic colorectal cancer (CRC). Detection of coexisting mutations within the same pathway, which are usually mutually exclusive, raises the concern for potential laboratory errors. In this retrospective study for quality assessment of a next-generation sequencing assay, we examined BRAF, KRAS, and NRAS genes within the mitogen-activated protein kinase (MAPK) pathway and the PIK3CA gene within the phosphatidylinositol 3-kinase (mTOR) pathway in 744 CRC specimens submitted to our clinical diagnostics laboratory. Although coexistence of mutations between the MAPK and mTOR pathways was observed, it rarely occurred within the MAPK pathway. Retrospective quality assessments identified false detection of coexisting activating KRAS and NRAS mutations in 1 specimen and confirmed 2 activating KRAS mutations in 2 specimens and coexisting activating KRAS and NRAS mutations in 2 specimens, but no coexisting activating RAS and BRAF mutations. There were 15 CRCs with a kinase-impaired BRAF mutation, including 3 with a coexisting activating KRAS mutation, which may have therapeutic implications. Multiregional analysis based on different histologic features demonstrated that coexisting KRAS and NRAS mutations may be present in the same or different tumor populations and showed that invasion of adenomas by synchronous adenocarcinomas of different clonal origin may result in detection of coexisting mutations within the MAPK pathway. In this study, we proposed an operating procedure for clinical validation of unexpected coexisting mutations. Further studies are warranted to elucidate the biological significance and clinical implications of coexisting mutations within the MAPK pathway.

Mechanism of Resistance to Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors and a Potential Treatment Strategy

Treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) improves the overall survival of patients with EGFR-mutated non-small-cell lung cancer (NSCLC). First-generation EGFR-TKIs (e.g., gefitinib and erlotinib) or second-generation EGFR-TKIs (e.g., afatinib and dacomitinib) are effective for the treatment of EGFR-mutated NSCLC, especially in patients with EGFR exon 19 deletions or an exon 21 L858R mutation. However, almost all cases experience disease recurrence after 1 to 2 years due to acquired resistance. The EGFR T790M mutation in exon 20 is the most frequent alteration associated with the development of acquired resistance. Osimertinib-a third-generation EGFR-TKI-targets the T790M mutation and has demonstrated high efficacy against EGFR-mutated lung cancer. However, the development of acquired resistance to third-generation EGFR-TKI, involving the cysteine residue at codon 797 mutation, has been observed. Other mechanisms of acquired resistance include the activation of alternative pathways or downstream targets and histological transformation (i.e., epithelial⁻mesenchymal transition or conversion to small-cell lung cancer). Furthermore, the development of primary resistance through overexpression of the hepatocyte growth factor and suppression of Bcl-2-like protein 11 expression may lead to problems. In this report, we review these mechanisms and discuss therapeutic strategies to overcome resistance to EGFR-TKIs.

HOTAIR, a long noncoding RNA, is a marker of abnormal cell cycle regulation in lung cancer

Dysregulation of the cell cycle is a key indicator of tumors, including lung cancer. Recently, the study of cell cycle inhibitors has made great progress in relation to lung cancer. However, the question of what kinds of patients can use cell cycle inhibitors has plagued us. Therefore, seeking an accurate and convenient marker for the abnormal cell cycle in lung cancer is very important. In the present research, we showed that lncRNA HOTAIR is an optimal indicator of cell cycle dysregulation in lung cancer. In the present study, we investigated HOTAIR‐specific expression in lung primary tumor samples by analyzing the TCGA public database and 67 pairs of patients’ tissues collected from our department. Through the TCGA public database KEGG analysis, HOTAIR correlates with the cell cycle pathway. We identified that HOTAIR and its 2 segments, HOTAIR3′ and HOTAIR5′, promote the cell cycle passing through the restriction point during G1‐S phase by regulating the Rb‐E2F pathway and influence non–small‐cell lung cancer cell proliferation, migration and invasion through epithelial‐mesenchymal transition (EMT) and the β‐catenin pathway in vitro and vivo. Finally, we showed that the high expression of HOTAIR was associated with resistance to gefitinib through the dysregulated cell cycle. In conclusion, HOTAIR could be an ideal indicator of cell cycle dysregulation and guide the use of cell cycle inhibitors.

Clinical Validation of Coexisting Activating Mutations Within EGFR, Mitogen-Activated Protein Kinase, and Phosphatidylinositol 3-Kinase Pathways in Lung Cancers

CONTEXT.—

Mutations within the same signature transduction pathway are redundant and, therefore, most are mutually exclusive. Laboratory errors, however, may introduce unexpected coexisting mutations.

OBJECTIVE.—

To validate coexisting mutations within epidermal growth factor receptor (EGFR), mitogen-activated protein kinase, and phosphatidylinositol 3-kinase pathways.

DESIGN.—

In this retrospective study for quality assessment of next-generation sequencing in a clinical diagnostics setting, coexisting mutations within EGFR, KRAS, NRAS, BRAF, AKT1, and PIK3CA genes were examined in 1208 non-small cell lung cancers.

RESULTS.—

EGFR mutations did not coexist with BRAF mutations, neither kinase-activated nor kinase-impaired mutations. There was a low but similar incidence (3.3%-5.1%) of PIK3CA mutations in BRAF-, EGFR-, and KRAS-mutated lung cancers and a rare incidence of coexisting KRAS and EGFR mutations detected in 1 of 1208 lung cancers (0.08%) or 1 of 226 EGFR-mutated lung cancers (0.4%). Coexisting BRAF p.V600E mutation was observed in 3 of 4 AKT1 p.E17K-mutated lung cancers. Mutational profiling of DNA reisolated from subareas with the same or different histomorphology, using an alternative assay, confirmed that coexisting mutations might present within the same (whole or subclonal) population or different populations and clarified that the so-called coexisting activating KRAS and BRAF mutations originally reported in a specimen were indeed present in separate lung nodules submitted in the same block.

CONCLUSIONS.—

The results supported that EGFR and BRAF mutations are early driver mutations in lung cancers. Guidelines from official organizations to establish standard operating procedures are warranted to validate unexpected coexisting mutations and, if clinically indicated, to determine their presence in the same or different tumor populations.

Cytology smears for DNA extraction: Practical approach for selecting the best slide

BACKGROUND

Next generation sequencing (NGS) to detect actionable genetic abnormalities is standard of care in advanced stage lung adenocarcinoma. Many studies have shown that the molecular results obtained from fine needle aspiration cytology material are comparable to those obtained from formalin-fixed tissue samples. We undertook this study to validate DNA extraction from cytology material for molecular studies and to find any correlation between DNA yield, pattern of tumour cells and tumour fraction.

METHODS

DNA was extracted from 34 cytology slides of pulmonary adenocarcinoma cases with predetermined EGFR mutation status. Cytology slides were reviewed for pattern of tumour distribution and tumour fraction. NGS was performed on five slides with variable DNA and compared with original results.

RESULTS

There were 14 alcohol-fixed and 20 air-dried smears. The mean DNA yield was 1.74 μg and median of 0.4 μg (range, 0.02-21 μg). Tumour fractions varied from 10% to 90%. No correlation was found between tumour fraction and DNA yield (P = 0.14). The mean DNA yield was high in slides with tumour throughout the slide (sheets or scattered clusters) as compared to rare scattered clusters and/or single cells. EGFR mutation was found in four of the five cases sent for NGS lung panel while one case revealed BRAF mutation.

CONCLUSIONS

DNA with good quantity and quality can be extracted from the cytology slides for NGS irrespective of type of fixation. DNA yield has better correlation with distribution pattern of tumour cells on the slides rather than tumour fraction.

[Research Progress of Targeted Therapy for BRAF Mutation in Advanced Non-small Cell Lung Cancer]

靶向治疗是驱动基因阳性晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）的重要治疗手段之一。鼠类肉瘤病毒癌基因同源物B1（v-raf murine sar-coma viral oncogene homolog B1, BRAF）基因是继表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变、间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）基因融合和ROS1基因重排之后，NSCLC又一个重要的驱动基因。BRAF V600E突变占BRAF基因突变的一半以上，是晚期NSCLC的潜在治疗靶点，本文主要对BRAF基因突变类型及相关靶向研究进展进行综述。。

Ground-glass nodules of the lung in never-smokers and smokers: clinical and genetic insights

Pulmonary ground-glass nodules (GGNs) are hazy radiological findings on computed tomography (CT). GGNs are detected more often in never-smokers. Retrospective and prospective studies have revealed that approximately 20% of pure GGNs and 40% of part-solid GGNs gradually grow or increase their solid components, whereas others remain stable for years. Most persistent or growing GGNs are lung adenocarcinomas or their preinvasive lesions. To distinguish GGNs with growth from those without growth, GGNs should be followed for at least 5 years. Lesion size and smoking history are predictors of GGN growth. Genetic analyses of resected GGNs have suggested that EGFR mutations are also predictors for growth but a subset of KRAS- or BRAF-mutated GGNs may undergo spontaneous regression because the frequencies of KRAS or BRAF mutations decrease with the advance of pathological invasiveness. Although lobectomy is the standard surgical procedure for lung cancer, limited surgery such as wedge resection or segmentectomy for lung cancers ≤2 cm with consolidation/tumor ratio ≤0.25 can be a viable alternative based on the recent clinical trial. Further genetic analyses and clinical trials can contribute to elucidation of the biological aspects of preinvasive adenocarcinoma and the development of less invasive management strategies for patients with GGNs.

Distribution of KRAS, DDR2, and TP53 gene mutations in lung cancer: An analysis of Iranian patients

Purpose

Lung cancer is the deadliest known cancer in the world, with the highest number of mutations in proto-oncogenes and tumor suppressor genes. Therefore, this study was conducted to determine the status of hotspot regions in DDR2 and KRAS genes for the first time, as well as in TP53 gene, in lung cancer patients within the Iranian population.

Experimental design

The mutations in exon 2 of KRAS, exon 18 of DDR2, and exons 5–6 of TP53 genes were screened in lung cancer samples, including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) using PCR and sequencing techniques.

Results

Analysis of the KRAS gene showed only a G12C variation in one large cell carcinoma (LCC) patient, whereas variants were not found in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) cases. The Q808H variation in the DDR2 gene was detected in one SCC sample, while no variant was seen in the ADC and LCC subtypes. Variations in the TP53 gene were seen in all NSCLC subtypes, including six ADC (13.63%), seven SCC (15.9%) and two LCC (4.54%). Forty-eight variants were found in the TP53 gene. Of these, 15 variants were found in coding regions V147A, V157F, Q167Q, D186G, H193R, T211T, F212L and P222P, 33 variants in intronic regions rs1625895 (HGVS: c.672+62A>G), rs766856111 (HGVS: c.672+6G>A) and two new variants (c.560-12A>G and c.672+86T>C).

Conclusions

In conclusion, KRAS, DDR2, and TP53 variants were detected in 2%, 2.17% and 79.54% of all cases, respectively. The frequency of DDR2 mutation is nearly close to other studies, while KRAS and TP53 mutation frequencies are lower and higher than other populations, respectively. Three new putative pathogenic variants, for the first time, have been detected in Iranian patients with lung cancer, including Q808H in DDR2, F212L, and D186G in coding regions of TP53. In addition, we observed five novel benign variants, including Q167Q, P222P and T211T in coding sequence, and c.560-12A>G and c.672+86T>C, in intronic region of TP53. Mutations of KRAS and DDR2 were found in LCC and SCC subtypes, respectively, whereas mutations of TP53 were seen in SCC and ADC subtypes with higher frequencies and LCC subtype with lower frequency. Therefore, Iranian lung cancer patients can benefit from mutational analysis before starting the conventional treatment. A better understanding of the biology of these genes and their mutations will be critical for developing future targeted therapies.

Next‑generation sequencing‑based detection of EGFR, KRAS, BRAF, NRAS, PIK3CA, Her‑2 and TP53 mutations in patients with non‑small cell lung cancer

In recent years, the incidence of non‑small cell lung cancer (NSCLC) has become the highest lethal rate of cancer worldwide. Molecular assays of EGFR, KRAS, BRAF, NRAS, PIK3CA and Her‑2 are widely used to guide individualized treatment in NSCLC patients. Somatic mutations in 112 NSCLC patients, including 7 oncogenic driver genes, were detected by Iontorrent personal genome machine (PGM). Sanger sequencing was used to test and verify the results of PGM. Apart from uncommon mutations of EGFR, 101 NSCLC specimens were tested by droplet digital PCR (ddPCR). According to NGS results, mutations were detected in EGFR (58/112, 51.79% of tumors), KRAS (10/112, 8.93%), BRAF (2/112, 1.79%), NRAS (2/112, 1.79%), Her‑2 (2/112, 1.79%), PIK3CA (6/112, 5.36%) and TP53 (31/112, 27.69%). There were 27 samples without any somatic mutations in all genes while 24 samples harboured mutations in two or more genes. A total of 61 samples had one or more mutations in a single gene. All alterations of 7 genes were presented and the overall detection rate of NGS and Sanger sequencing was determined to be 51.79% (58/112) and 37.50% (42/112), respectively (χ2=5.88, P=0.015). Compared with Sanger sequencing, the total sensitivity and specificity of NGS assays was 95.24% (40/42) and 77.14% (54/70), respectively. The overall detection rate of NGS and ddPCR was 45.54% (46/101) and 47.52% (48/101), respectively (χ2=0.000598, P=0.98). Compared with ddPCR, the overall sensitivity and specificity of NGS assays was 95.83% (46/48) and 98.11% (52/53), respectively. The findings indicated that the positive mutation rate of EGFR tested by NGS was significantly lower than that by Sanger sequencing, but the difference between ddPCR and NGS was not statistically significant. The high degree of agreement of reportable variants is proposed in both NGS and ddPCR analysis, suggesting the performance of NGS assays in routine clinical detection may be useful in determining the treatment decisions in NSCLC patients.

Genomic alterations of ground-glass nodular lung adenocarcinoma

In-depth molecular pathogenesis of ground-glass nodular lung adenocarcinoma has not been well understood. The objectives of this study were to identify genomic alterations in ground-glass nodular lung adenocarcinomas and to investigate whether viral transcripts were detected in these tumors. Nine patients with pure (n = 4) and part-solid (n = 5) ground-glass nodular adenocarcinomas were included. Six were females with a median age of 58 years. We performed targeted exon sequencing and RNA sequencing. EGFR (n = 10), IDH2 (n = 2), TP53 (n = 1), PTEN (n = 1), EPHB4 (n = 1), and BRAF (n = 1) were identified as driver mutations by targeted exon sequencing. Vasculogenesis-associated genes including NOTCH4 and TGFBR3 expression were significantly downregulated in adenocarcinoma tissue versus normal tissue (adjusted P values < 0.001 for both NOTCH4 and TGFBR3). In addition, five novel fusion gene loci were identified in four lung adenocarcinomas. However, no significant virus-associated transcripts were detected in tumors. In conclusions, EGFR, IDH2, TP53, PTEN, EPHB4, and BRAF were identified as putative driver mutations of ground-glass nodular adenocarcinomas. Five novel fusion genes were also identified in four tumors. Viruses do not appear to be involved in the tumorigenesis of ground-glass nodular lung adenocarcinoma.

Mutational profiling of non-small-cell lung cancer patients resistant to first-generation EGFR tyrosine kinase inhibitors using next generation sequencing

Patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitive epithelial growth factor receptor (EGFR) mutations invariably develop acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Identification of actionable genetic alterations conferring drug-resistance can be helpful for guiding the subsequent treatment decision. One of the major resistant mechanisms is secondary EGFR-T790M mutation. Other mechanisms, such as HER2 and MET amplifications, and PIK3CA mutations, were also reported. However, the mechanisms in the remaining patients are still unknown. In this study, we performed mutational profiling in a cohort of 83 NSCLC patients with TKI-sensitizing EGFR mutations at diagnosis and acquired resistance to three different first-generation EGFR TKIs using targeted next generation sequencing (NGS) of 416 cancer-related genes. In total, we identified 322 genetic alterations with a median of 3 mutations per patient. 61% of patients still exhibit TKI-sensitizing EGFR mutations, and 36% of patients acquired EGFR-T790M. Besides other known resistance mechanisms, we identified TET2 mutations in 12% of patients. Interestingly, we also observed SOX2 amplification in EGFR-T790M negative patients, which are restricted to Icotinib treatment resistance, a drug widely used in Chinese NSCLC patients. Our study uncovered mutational profiles of NSCLC patients with first-generation EGFR TKIs resistance with potential therapeutic implications.

The long tail of molecular alterations in non-small cell lung cancer: a single-institution experience of next-generation sequencing in clinical molecular diagnostics

BACKGROUND

Molecular profiling of advanced non-small cell lung cancers (NSCLC) is essential to identify patients who may benefit from targeted treatments. In the last years, the number of potentially actionable molecular alterations has rapidly increased. Next-generation sequencing allows for the analysis of multiple genes simultaneously.

AIMS

To evaluate the feasibility and the throughput of next-generation sequencing in clinical molecular diagnostics of advanced NSCLC.

METHODS

A single-institution cohort of 535 non-squamous NSCLC was profiled using a next-generation sequencing panel targeting 22 actionable and cancer-related genes.

RESULTS

441 non-squamous NSCLC (82.4%) harboured at least one gene alteration, including 340 cases (63.6%) with clinically relevant molecular aberrations. Mutations have been detected in all but one gene (FGFR1) of the panel. Recurrent alterations were observed in KRAS, TP53, EGFR, STK11 and MET genes, whereas the remaining genes were mutated in <5% of the cases. Concurrent mutations were detected in 183 tumours (34.2%), mostly impairing KRAS or EGFR in association with TP53 alterations.

CONCLUSIONS

The study highlights the feasibility of targeted next-generation sequencing in clinical setting. The majority of NSCLC harboured mutations in clinically relevant genes, thus identifying patients who might benefit from different targeted therapies.

Primary and acquired EGFR T790M-mutant NSCLC patients identified by routine mutation testing show different characteristics but may both respond to osimertinib treatment

Primary EGFR T790M mutation is occasionally identified by routine mutation testing in tyrosine kinase inhibitor (TKI)-naive patients with non-small cell lung cancer (NSCLC). We herein aimed to compare the characteristics of primary and acquired T790M mutations in NSCLC patients, and their response to osimertinib. Using amplification refractory mutation system (ARMS) detection, primary T790M was identified in 0.5% (46/8723) of TKI-naive patients, whereas acquired T790M was detected in 49.7% (71/143) of TKI-relapsed patients. T790M always coexisted with a sensitizing EGFR mutation. Primary T790M more commonly coexisted with L858R, whereas acquired T790M was more likely to coexist with exon 19 deletions. Moreover, next-generation sequencing (NGS) showed that concomitant sensitizing EGFR and primary T790M mutant allele frequencies (MAFs) were highly concordant, but acquired T790M MAFs were significantly lower than the sensitizing EGFR MAFs. Sixteen acquired T790M-mutant patients received osimertinib. The median progression-free survival (PFS) was 8.1 months. Four primary T790M-mutant patients received osimertinib and the median PFS was 8.0 months. Together, our study demonstrates that primary and acquired T790M-mutant patients show distinct differences in some clinical and molecular characteristics, but may both respond to osimertinib treatment.

Concurrent gene alterations with EGFR mutation and treatment efficacy of EGFR-TKIs in Chinese patients with non-small cell lung cancer

PURPOSE

We investigated the frequency of concurrent genes in EGFR-mutant non-small cell lung cancer patients and determined its value in predicting the efficacy of EGFR-TKIs treatment.

METHODS

Three hundred and twenty patients, who harbored EGFR activating mutations and received EGFR-TKIs treatment, were examined for another eight genes including KRAS, NRAS, PIK3CA, BRAF, and HER2 mutations and ALK, ROS1, and RET fusion genes based on reverse transcription PCR. Progression-free survival and overall survival with EGFR-TKIs treatment were evaluated using Kaplan-Meier methods and compared between different patients using log-rank tests.

RESULTS

Twenty-one (6.6%) of 320 EGFR mutant samples with additional gene alterations were identified. The most common concurrent gene was PIK3CA mutation (n = 9), followed by EML4-ALK rearrangement (n = 6), HER2 mutation (n = 3), RET rearrangement (n = 1), ROS1 rearrangement (n = 1) and KRAS mutation (n = 1). Patients with single EGFR mutation had a significantly longer progression-free survival than those with concurrent genes (10.9 vs. 6.0 months, P = 0.002). Among the 21 cases, patients with PIK3CA mutation had the longest median progression-free survival (7.6 months), followed by ALK rearrangement (5.0 months) and other gene types (1.2 months). No overall survival difference was found between patients with single EGFR mutation and concurrent gene alterations (21.0 vs.17.6 months, P = 0.17).

CONCLUSION

We demonstrated that concurrent gene alterations occurred in some patients with EGFR mutations. Concurrent gene alterations decreased the efficacy of EGFR-TKIs.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

- In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

- To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

- The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

- Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

- The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes ( ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Clinicopathologic characteristics of EGFR, KRAS, and ALK alterations in 6,595 lung cancers

BACKGROUND

EGFR, KRAS, and ALK alterations are major genetic changes found in non-small cell lung cancers (NSCLCs). Testing advanced lung adenocarcinoma tumors for these three genes is now standard care. The purpose of this study was to investigate the clinicopathologic expression pattern of these three genes in East Asian NSCLC patients.

PATIENTS AND METHODS

We conducted a retrospective study of all patients tested for mutations of these three genes at a single institute in Korea between 2006 and 2014. Study data were extracted from electronic medical records. Univariate and multivariate logistic regression analyses were used to measure associations between clinicopathologic features and alterations of EGFR, KRAS, and ALK.

RESULTS

We detected 12 EGFR-mutated tumors with additional mutations in KRAS (N=6, 0.1%) or ALK (N=6, 0.1%). General clinicopathologic characteristics of tumors with EGFR, KRAS, or ALK mutations were similar to previous reports. Patients having EGFR L858R point mutations were older than patients having EGFR exon 19 deletions. EGFR G719X point mutations were more common in men and smokers than exon 19 deletions or L858R point mutations. Tumors having KRAS G12C mutations were less often of mucinous type than those with G12D or G12V, mutations.

CONCLUSIONS

This is the largest three gene molecular epidemiology study in East Asian NSCLC patients. Each genetic alteration was associated with distinct clinicopathologic characteristics. Furthermore, different age and sex are associated with different subtypes of EGFR and KRAS mutations.

PD 0332991, a selective cyclin D kinase 4/6 inhibitor, sensitizes lung cancer cells to treatment with epidermal growth factor receptor tyrosine kinase inhibitors

Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is a major challenge to targeted therapy for non-small cell lung cancer (NSCLC). We investigated whether a cyclin D kinase 4/6 (CDK4/6) inhibitor, PD 0332991, could reverse EGFR-TKI resistance in human lung cancer cells and explored the underlying mechanisms. We found that PD 0332991 potentiated gefitinib-induced growth inhibition in both EGFR-TKI-sensitive (PC-9) and EGFR-TKI-resistant (PC-9/AB2) cells by down-regulating proliferation and inducing apoptosis and G0/G1 cell cycle arrest. Tumor xenografts were then used to verify the effects of PD 0332991 in vivo. Mice treated with a combination of PD 0332991 and gefitinib had the fastest tumor regression and delayed relapse. Tumors from mice receiving the combination treatment exhibited down-regulated proliferation, up-regulated apoptosis, and less angiogenesis. Finally, lung adenocarcinoma patients with acquired resistance to EGFR-TKIs were given an exploratory treatment of PD 0332991. One patient with gefitinib resistance exhibited clinical remission after treatment with PD 0332991. These findings suggest PD 0332991 reverses acquired EGFR-TKI-resistance in NSCLC cells, and may provide a novel treatment strategy for NSLSC patients with EGFR-TKI resistance.

KRAS oncogene in non-small cell lung cancer: clinical perspectives on the treatment of an old target

Lung neoplasms are the leading cause of death by cancer worldwide. Non-small cell lung cancer (NSCLC) constitutes more than 80% of all lung malignancies and the majority of patients present advanced disease at onset. However, in the last decade, multiple oncogenic driver alterations have been discovered and each of them represents a potential therapeutic target. Although KRAS mutations are the most frequently oncogene aberrations in lung adenocarcinoma patients, effective therapies targeting KRAS have yet to be developed. Moreover, the role of KRAS oncogene in NSCLC remains unclear and its predictive and prognostic impact remains controversial. The study of the underlying biology of KRAS in NSCLC patients could help to determine potential candidates to evaluate novel targeted agents and combinations that may allow a tailored treatment for these patients. The aim of this review is to update the current knowledge about KRAS-mutated lung adenocarcinoma, including a historical overview, the biology of the molecular pathways involved, the clinical relevance of KRAS mutations as a prognostic and predictive marker and the potential therapeutic approaches for a personalized treatment of KRAS-mutated NSCLC patients.

Epidermal growth factor receptor somatic mutation analysis in 354 Chinese patients with non-small cell lung cancer

Lung cancer is one of the most common types of cancer worldwide, with the highest mortality rate of all types of cancer. In the present study, epidermal growth factor receptor (EGFR) mutations of 354 primary patients with non-small cell lung cancer (NSCLC) of Chinese ethnicity were detected following formalin-fixed and paraffin-embedded specimen DNA extraction, polymerase chain reaction amplification, and sanger sequencing. The total rate of occurrence of EGFR somatic mutation in these 354 patients was 48.02%. Of these detected EGFR mutations, 27.40% were located in exon 19 and 25.99% in exon 21. The most frequent mutation in exon 19 was E746-A750del (8.47%), and in exon 21, L858R (10.17%). EGFR mutation rates were significantly associated with sex [female vs. male: 60.13 vs. 38.81%; adjusted odds ratio (OR), 1.93, 95% confidence interval (CI), 1.07–3.51, P=0.029], age (<60 vs. ≥60; 58.62 vs. 40.67%; adjusted OR, 1.87; 95% CI, 1.20–2.92; P=0.006) and histology [adenocarcinoma (ADC) vs. non-ADC; 52.76 vs. 26.56%; adjusted OR, 2.35; 95% CI, 1.28–4.50; P=0.007]. The frequency of E746_A750del, Q787Q and L858R mutations were significantly different in ADC patients compared with squamous cell carcinoma patients (P<0.001). Furthermore, a novel EGFR mutation, M793K, was detected in 7 NSCLC patients with possible gefitinib resistance. The present study analyzed the EGFR exon 18–21 mutation occurrence profile for Chinese patients with NSCLC and identified significant associations between different EGFR mutations with demographic and histological factors. These results may offer clinical benefits and potential novel treatments.

Overexpression of mutant EGFR protein indicates a better survival benefit from EGFR-TKI therapy in non-small cell lung cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) is a novel target for therapy in a subset of non-small cell lung cancer (NSCLC). Tumors with EGFR mutations showed good response to EGFR tyrosine kinase inhibitors (TKIs). We aimed to identify the discriminating capacity of immunohistochemistry (IHC) to detect EGFR L858R and del E746-A750 mutations in NSCLC patients and predict EGFR TKIs response.

METHODS

We collected specimens from 200 patients with NSCLC whose EGFR mutation status had been validated by direct DNA sequencing. IHC analyses using EGFR mutation-specific antibodies were employed for all samples. After staining and scoring, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

RESULTS

The sensitivity, specificity, PPV, and NPV of IHC using EGFR del E746-A750 and L858R mutation antibodies were 95.0%/95.1%, 85.7%/94.1%, 74.0%/91.8%, and 97.6%/96.5%, respectively. When score 2+ and 3+ were considered as positive, the sensitivity, specificity, PPV, and NPV were 53.3%/36.6%, 99.3%/100%, 97.0%/100%, and 83.2%/65.3%, respectively. The median progression-free survival (PFS) after the start of gefitinib treatment was significantly longer in patients with a high score for mutant EGFR expression than in those with a low score (31.0 versus 13.0 months, p <0.05).

CONCLUSIONS

IHC with EGFR mutation-specific antibodies is a promising screening method for detecting EGFR mutations in NSCLC patients. Otherwise, quantitative analysis of mutant EGFR expression might also predict the efficacy of TKIs treatment for NSCLC patients harboring sensitive EGFR mutation.

Comprehensive profiling and quantitation of oncogenic mutations in non small-cell lung carcinoma using single molecule amplification and re-sequencing technology

Activating and resistance mutations in the tyrosine kinase domain of several oncogenes are frequently associated with non-small cell lung carcinoma (NSCLC). In this study we assessed the frequency, type and abundance of EGFR, KRAS, BRAF, TP53 and ALK mutations in tumour specimens from 184 patients with early and late stage disease using single molecule amplification and re-sequencing technology (SMART). Based on modelling of EGFR mutations, the detection sensitivity of the SMART assay was at least 0.1%. Benchmarking EGFR mutation detection against the gold standard ARMS-PCR assay, SMART assay had a sensitivity and specificity of 98.7% and 99.0%. Amongst the 184 samples, EGFR mutations were the most prevalent (59.9%), followed by KRAS (16.9%), TP53 (12.7%), EML4-ALK fusions (6.3%) and BRAF (4.2%) mutations. The abundance and types of mutations in tumour specimens were extremely heterogeneous, involving either monoclonal (51.6%) or polyclonal (12.6%) mutation events. At the clinical level, although the spectrum of tumour mutation(s) was unique to each patient, the overall patterns in early or advanced stage disease were relatively similar. Based on these findings, we propose that personalized profiling and quantitation of clinically significant oncogenic mutations will allow better classification of patients according to tumour characteristics and provide clinicians with important ancillary information for treatment decision-making.

Frequency of T790M mutations after progression on epidermal growth factor receptor tyrosine kinase inhibitor in metastatic non-small cell lung cancer in Indian patients: real-time data from tertiary cancer hospital

Aim

The aim of this study is to determine the incidence of T790M mutations after progression on epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) and median duration on TKI before progression on TKI.

Methods

Records of Rajiv Gandhi Cancer Institute and Research Centre, of patients who were diagnosed with metastatic adenocarcinoma of the lung and progressed on oral EGFR TKIs and underwent T790M mutation analysis in the last 6 months were retrospectively reviewed. The incidence of T790M positivity, sites of progression, and median duration of TKI treatment before progression was calculated.

Results

Among 31 patients, 10 patients have undergone rebiopsy, and 24 patients had undergone liquid biopsy by Droplet Digital polymerase chain reaction (ddPCR), and three patients had undergone both tests. Among all, the rate of T790M positivity was 54.8%. Among these 17 patients positive for T790M, seven patients were positive by biopsy, and 11 patients were positive by ddPCR. Among three patients who underwent both, one was positive by both. The most common site of progression among all patients is pleura, and 10% of patients progressed in brain post-TKI. Median progression-free survival on TKI before progression is 289.7 days, highest being 1290 days, and lowest 45 days.

Conclusions

Exact incidence of T790M mutations after progression on TKI s in Asian population is not exactly known and requires large data, as incidence may be different than reported in the Western population. Rebiopsy and ddPCR help to determine the most common type of resistance after progression on TKI, for which effective targeted therapy is available.

Mechanisms of resistance to irreversible epidermal growth factor receptor tyrosine kinase inhibitors and therapeutic strategies in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) T790M mutation is the most frequent mechanism which accounts for about 60% of acquired resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients harboring EGFR activating mutations. Irreversible EGFR-TKIs which include the second-generation and third-generation EGFR-TKIs are developed to overcome T790M mediated resistance. The second-generation EGFR-TKIs inhibit the wide type (WT) EGFR combined with dose-limiting toxicity which limits its application in clinics, while the development of third-generation EGFR-TKIs brings inspiring efficacy either in vitro or in vivo. The acquired resistance, however, will also occur and limit their response. Understanding the mechanisms of resistance to irreversible EGFR-TKIs plays an important role in the choice of subsequent treatment. In this review, we show the currently known mechanisms of resistance which can be summarized as EGFR dependent and independent mechanisms and potential therapeutic strategies to irreversible EGFR-TKIs.

Concurrent driver mutations/rearrangements in non-small-cell lung cancer

PURPOSE OF REVIEW

The concept of mutually exclusive oncogenic driver alterations has prevailed over the past decade, but recent reports have stressed the possible occurrence of dual-positive non-small-cell lung cancer (NSCLC) and even triple-positive disease for these oncogenes. This entity presents novel prognostic and therapeutic challenges. The present review highlights the available data in an effort to clarify the clinical and pathological significance of coexisting mutations as well as the subsequent therapeutic consequences.

RECENT FINDINGS

Patients with a known driver oncogene can be successfully treated with the appropriate tyrosine kinase inhibitor, which will provide them with significant responses and lesser toxicities compared with cytotoxic therapy. Unfortunately, most patients will eventually progress. Although some resistance mechanisms have been identified, others remain to be determined but the emergence of secondary oncogenes could be part of the answer.

SUMMARY

Approximately 20-25% of NSCLC harbor treatable driver mutations/rearrangements; epidermal growth factor receptor mutation, anaplastic lymphoma kinase and ROS-1 gene rearrangements are the main alterations for which a Food and Drug Administration-approved tyrosine kinase inhibitor can be used.Because of recent technological advances, high sensitivity assays with a broad range of genomic targets have become more easily accessible in clinical practice, which has led to an increased detection of coexisting driver alterations in patients with advanced NSCLC. The prognostic/predictive and therapeutic implications of this novel entity are still unsettled for the time being. Randomized trials specifically designed to address this subset of patients will soon be necessary to help determine the optimal therapeutic agent to administer.

ALK and ROS1 concurrent with EGFR mutation in patients with lung adenocarcinoma

PURPOSE

The purpose of this study was to explore the frequencies of ALK and ROS1 fusion genes in EGFR-mutant lung adenocarcinoma patients and examine the therapeutic efficacies of EGFR-tyrosine kinase inhibitors (TKIs).

MATERIALS AND METHODS

A total of 421 EGFR-mutated patients taking EGFR-TKIs were examined for ALK and ROS1 fusion genes based on reverse transcription-polymerase chain reaction (RT-PCR). Progression-free survival (PFS) and overall survival (OS) were evaluated by the Kaplan-Meier method and compared by the log-rank test.

RESULTS

The mutations of ALK rearrangement (n=10) and ROS1 rearrangement (n=3) were detected. All the patients received EGFR-TKIs, and eight took subsequent ALK/ROS1 inhibitor. PFS was longer in single EGFR mutants (n=408) than in EGFR/ALK or EGFR/ROS1 counterparts (n=13; 10.7 vs 6.6 months, P=0.004). No difference in OS existed between single EGFR and EGFR/ALK or EGFR/ROS1 mutants (21.0 vs 23.0 months, P=0.196). The median PFS of eight patients treated with ALK/ROS1 inhibitor was 6.0 months.

CONCLUSION

Concomitant ALK/ROS1 fusion genes occurred in 3.1% EGFR-mutated lung adenocarcinoma patients. Concomitant ALK/ROS1-EGFR mutations may influence the therapeutic efficacy of EGFR-TKIs.

Clinical mutational profiling of 1006 lung cancers by next generation sequencing

Analysis of lung adenocarcinomas for actionable mutations has become standard of care. Here, we report our experience using next generation sequencing (NGS) to examine AKT1, BRAF, EGFR, ERBB2, KRAS, NRAS, and PIK3CA genes in 1006 non-small cell lung cancers in a clinical diagnostic setting. NGS demonstrated high sensitivity. Among 760 mutations detected, the variant allele frequency (VAF) was 2–5% in 33 (4.3%) mutations and 2–10% in 101 (13%) mutations. A single bioinformatics pipeline using Torrent Variant Caller, however, missed a variety of EGFR mutations. Mutations were detected in KRAS (36% of tumors), EGFR (19%) including 8 (0.8%) within the extracellular domain (4 at codons 108 and 4 at codon 289), BRAF (6.3%), and PIK3CA (3.7%). With a broader reportable range, exon 19 deletion and p.L858R accounted for only 36% and 26% of EGFR mutations and p.V600E accounted for only 24% of BRAF mutations. NGS provided accurate sequencing of complex mutations seen in 19% of EGFR exon 19 deletion mutations. Doublet (compound) EGFR mutations were observed in 29 (16%) of 187 EGFR-mutated tumors, including 69% with two non-p.L858R missense mutations and 24% with p.L858 and non-p.L858R missense mutations. Concordant VAFs suggests doublet EGFR mutations were present in a dominant clone and cooperated in oncogenesis. Mutants with predicted impaired kinase, observed in 25% of BRAF-mutated tumors, were associated with a higher incidence of concomitant activating KRAS mutations. NGS demonstrates high analytic sensitivity, broad reportable range, quantitative VAF measurement, single molecule sequencing to resolve complex deletion mutations, and simultaneous detection of concomitant mutations.

[Progress in the Treatment of Non-small Cell Lung Cancer with BRAF Inhibitors]

In recent years, targeted drugs occupy a pivotal position in the treatment of non-small cell lung cancer (NSCLC), drugs targeting epidermal growth factor receptor (EGFR) has been widely used in clinical practice, it is of milestone significance. V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors targeted at BRAF gene have obviously clinical efficacy to specific advantages populations with little side-effect, and be well tolerated. It is discovered recently that drug resistance also exists in BRAF inhibitors like other targeted drugs, the mechanism of drug resistance is being studied. In this paper, a review were performed in the mechanism, clinical application, adverse reactions and the drug resistance of BRAF inhibitors.

Coexistence of EGFR, KRAS, BRAF, and PIK3CA Mutations and ALK Rearrangement in a Comprehensive Cohort of 326 Consecutive Spanish Nonsquamous NSCLC Patients

INTRODUCTION

Molecular screening is crucial for the care of nonsquamous non-small-cell lung cancer (NSCLC) patients. The coexistence of mutations could have important consequences regarding treatment. We described the mutational patterns and coexistence among patients and their outcomes after targeted treatment.

MATERIALS AND METHODS

Data from consecutive patients with newly diagnosed nonsquamous NSCLC were prospectively collected. Next-generation sequencing analysis of mutational hotspots in the EGFR, KRAS, PIK3CA, and BRAF genes and analysis of anaplastic lymphoma kinase (ALK) rearrangement were performed.

RESULTS

A total of 326 patients with nonsquamous NSCLC were identified. Of the 326 patients, 240 (73.6%) had EGFR, 141 (43.3%) KRAS, 137 (42.0%) BRAF, 130 (39.9%) PIK3CA mutation and 148 (45.4%) ALK rearrangement determined. Of the 240 with EGFR determination, 24.1% harbored EGFR mutations. Of these, 16.3% were activating mutations (43.6%, exon 19 deletion; 46.1%, exon 21; and 10.3%, exon 18) and 7.9% were nonsensitizing EGFR mutations. Furthermore, 39.0% had KRAS mutations, 2.9% BRAF mutations, 10.0% PIK3CA mutations, and 8.8% ALK rearrangements. Of the 154 stage IV patients with ≥ 1 mutations, analysis showed 19 coexisting cases (12.3%). Of 8 patients receiving targeted treatment, 6 had no response. Both responders to targeted treatment had coexistent PIK3CA mutations.

CONCLUSION

Driver mutations can coexist in nonsquamous NSCLC. In our cohort, 12.3% of cases with stage IV disease had multiple mutations. Targeted treatment might not be as effective in patients with coexisting mutations; however, coexistence with PIK3CA might not preclude a response.

Molecular biomarkers for lung adenocarcinoma

The identification of oncogenic driver alterations that underlie sensitivity to small inhibitors has led to growing interest in identifying additional targetable oncogenes in nonsmall cell lung cancer. Although the therapeutic impact of the discovery of these alterations has now been widely demonstrated, the epidemiological data associated with each of these biomarkers remain insufficiently studied. In this review, we discuss the techniques used to discover each of these candidate oncogenes, their prevalence in nonsmall cell lung cancer, and briefly outline the epidemiological features of the major oncogenes and ways in which their identification can determine therapeutic strategies.

Circulating Tumor DNA Mutation Profiling by Targeted Next Generation Sequencing Provides Guidance for Personalized Treatments in Multiple Cancer Types

Cancer is a disease of complex genetic alterations, and comprehensive genetic diagnosis is beneficial to match each patient to appropriate therapy. However, acquisition of representative tumor samples is invasive and sometimes impossible. Circulating tumor DNA (ctDNA) is a promising tool to use as a non-invasive biomarker for cancer mutation profiling. Here we implemented targeted next generation sequencing (NGS) with a customized gene panel of 382 cancer-relevant genes on 605 ctDNA samples in multiple cancer types. Overall, tumor-specific mutations were identified in 87% of ctDNA samples, with mutation spectra highly concordant with their matched tumor tissues. 71% of patients had at least one clinically-actionable mutation, 76% of which have suggested drugs approved or in clinical trials. In particular, our study reveals a unique mutation spectrum in Chinese lung cancer patients which could be used to guide treatment decisions and monitor drug-resistant mutations. Taken together, our study demonstrated the feasibility of clinically-useful targeted NGS-based ctDNA mutation profiling to guide treatment decisions in cancer.

Progression inference for somatic mutations in cancer

Computational methods were employed to determine progression inference of genomic alterations in commonly occurring cancers. Using cross-sectional TCGA data, we computed evolutionary trajectories involving selectivity relationships among pairs of gene-specific genomic alterations such as somatic mutations, deletions, amplifications, downregulation, and upregulation among the top 20 driver genes associated with each cancer. Results indicate that the majority of hierarchies involved TP53, PIK3CA, ERBB2, APC, KRAS, EGFR, IDH1, VHL, etc. Research into the order and accumulation of genomic alterations among cancer driver genes will ever-increase as the costs of nextgen sequencing subside, and personalized/precision medicine incorporates whole-genome scans into the diagnosis and treatment of cancer.

Determining EGFR-TKI sensitivity of G719X and other uncommon EGFR mutations in non-small cell lung cancer: Perplexity and solution (Review)

Mutations in epidermal growth factor receptor (EGFR) play critical roles in the pathogenesis of non-small cell lung cancer (NSCLC), and they are highly associated with sensitivity to tyrosine kinase inhibitors (TKIs). While the pathogenic and pharmacological characteristics of common mutations in EGFR have been thoroughly investigated, those of uncommon mutations remain to be elucidated. Traditional approaches to study common mutations by randomized controlled trials are not feasible for uncommon mutations owing to their rarity. Therefore, by systematically reviewing laboratory and clinical studies of the G719X mutation, one of the uncommon mutations, we concluded that the G719X mutation was intermediately sensitive to TKIs, with an average response rate of 35.1% (47/134). Moreover, accordingly, we proposed a comprehensive model to investigate uncommon mutations in EGFR. The model involves both basic and clinical components, composed of structural analyses, functional alterations, cell viabilities and animal models with various types of clinical studies. In this review, we systematically reviewed studies of the G719X mutation and put forward a research model that could be generalized to explore uncommon mutations in diseases associated with gene mutations.

[Research Progress of Targeted Therapy for Anaplastic Lymphoma Kinase and Other Rare Driver Genes in Advanced Non-small Cell Lung Cancer]

Targeted therapy was one of the major treatments in advanced non-small cell lung cancer (NSCLC) with positive driver genes. This area of research progresses day by day, with novel target discoveries, novel drug development, and use of novel combination treatments. Researchers have also undergone deep investigation about the molecular mechanisms underlying inherent or acquired resistance to these targeted therapies. This review aimed to summarize the advanced developments of targeted therapy for anaplastic lymphoma kinase (ALK) and other rare driver genes in NSCLC.

Assessment of cytology based molecular analysis to guide targeted therapy in advanced non-small-cell lung cancer

To investigate the use of molecular testing on cytological specimens in selecting advanced non-small cell lung cancer (NSCLC) patients who are adequate for targeted treatment, a total of 137 NSCLC cases were analyzed by fluorescence in situ hybridization (FISH) for anaplastic lymphoma kinase (ALK) rearrangements, and Epidermal growth factor receptor (EGFR), kirsten rat sarcoma viral oncogene homolog (KRAS) mutations were evaluated by quantitative real-time PCR (qRT-PCR) platform combining amplification refractory mutation system (ARMS) primers and TaqMan probes. Cytological specimens included 91 fine-needle aspirates, 5 fibreoptic bronchoscopic derived samples and 41 pleural effusions. Among 137 NSCLCs analyzed for ALK FISH, 16 (11.7%, of 137) were detected to harbor ALK rearrangement. FISH positive cases were all defined as adenocarcinoma (ADC) histologic subtype and the FNA samples showed the highest ALK positive rate (13.2%, 12/91). Of the 9 ALK FISH positive patients who received crizotinib treatment, 8 (88.9%) patients exhibited tumor regression. In addition, 60 (44.8%, of 134) cases were found to harbor EGFR mutations and 22 patients with EGFR sensitive mutations who received gefitinib or erlotinib treatment showed a median PFS of 16.0 months. Mutations of KRAS occurred in 8 (6.0%, of 134) cases and this was mutually exclusive from EGFR mutation. Our results demonstrated that ALK FISH and EGFR, KRAS mutational analysis on cytological specimens are sensitive methods for screening advanced stage NSCLC patients who are adequate for targeted treatment.

KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC: A meta-analysis of 41 studies

Mutation of oncogene KRAS is common in non-small cell lung cancer (NSCLC), however, its clinical significance is still controversial. Independent studies evaluating its prognostic and predictive value usually drew inconsistent conclusions. Hence, We performed a meta-analysis with 41 relative publications, retrieved from multi-databases, to reconcile these controversial results and to give an overall impression of KRAS mutation in NSCLC. According to our findings, KRAS mutation was significantly associated with worse overall survival (OS) and disease-free survival (DFS) in early stage resected NSCLC (hazard ratio or HR=1.56 and 1.57, 95% CI 1.39-1.76 and 1.17-2.09 respectively), and with inferior outcomes of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) treatment and chemotherapy (relative risk or RR=0.21 and 0.66 for objective response rate or ORR, 95% CI 0.12-0.39 and 0.54-0.81 respectively; HR=1.46 and 1.30 for progression-free survival or PFS, 95%CI 1.23-1.74 and 1.14-1.50 respectively) in advanced NSCLC. When EGFR mutant patients were excluded, KRAS mutation was still significantly associated with worse OS and PFS of EGFR-TKIs (HR=1.40 and 1.35, 95 % CI 1.21-1.61 and 1.11-1.64). Although KRAS mutant patients presented worse DFS and PFS of chemotherapy (HR=1.33 and 1.11, 95% CI 0.97-1.84 and 0.95-1.30), and lower response rate to EGFR-TKIs or chemotherapy (RR=0.55 and 0.88, 95 % CI 0.27-1.11 and 0.76-1.02), statistical differences were not met. In conclusion, KRAS mutation is a weak, but valid predictor for poor prognosis and treatment outcomes in NSCLC. There's a need for developing target therapies for KRAS mutant lung cancer and other tumors.

BRAF V600E mutation in epilepsy-associated glioneuronal tumors: Prevalence and correlation with clinical features in a Chinese population

PURPOSE

Glioneuronal tumors (GNTs) are the most common histological type of brain tumors in patients who received epilepsy surgery, and part of them presented with BRAF V600E mutation. We aimed to verify the presence of the BRAF V600E mutation in epilepsy-associated GNTs from Chinese population and evaluate the association with clinical features.

METHODS

Data from 35 patients diagnosed with GNTs, including 24 gangliogliomas and 11 dysembryoplastic neuroepithelial tumors, were retrospectively collected. DNA was extracted from GNTs tissues and BRAF V600E mutation was examined by DNA sequencing. The correlations between BRAF V600E mutation and clinical features were analyzed.

RESULTS

Totally, BRAF V600E mutations were detected in 11 patients with GNTs, the rate of mutation were 33.3% and 27.3% in GGs (8/24) and DNTs (3/11), respectively. The probability of BRAF V600E mutation in females (7/12, 58.3%) was significantly higher than that in males (4/23, 17.4%) (P=0.022). Moreover, patients with BRAF-mutated GNTs had a significantly wider variety of seizure types compared to GNTs with BRAF wild-type status (P=0.027). However, no significant correlation between the BRAF status and certain clinical features, such as age of seizure onset, duration of epilepsy, age at surgery, location of the tumor and postoperative seizure free, were observed.

CONCLUSION

We demonstrated the presence of BRAF V600E mutation in Chinese epileptic patients with GNTs, which was significantly correlated with gender and multiple seizure types. Large sample studies and long-term follow-up are required for further confirmation.

Molecular Profiling and Survival of Completely Resected Primary Pulmonary Neuroendocrine Carcinoma

BACKGROUND

Currently, molecular profiles and prognosis of primary pulmonary neuroendocrine carcinoma (PNC) are poorly elucidated. The present study was designed to evaluate genomic abnormalities and survival in patients with primary PNC.

METHODS

Completely resected PNC samples were collected from Zhejiang Cancer Hospital during the period of 2008 to 2015. Nine driver genes, including 6 mutations (EGFR, KRAS, NRAS, PIK3CA, BRAF, and HER2) and 3 fusions (ALK, ROS1, and RET), were evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Survival analysis was conducted by the Kaplan-Meier method.

RESULTS

A total of 108 patients with pathologically confirmed PNC were enrolled. The types were pulmonary large-cell neuroendocrine carcinoma (PLCNC, n = 52), small-cell lung cancer (SCLC, n = 44), and carcinoid (n = 12). Twelve patients (11.1%) harbored genomic aberrations. The most frequent gene abnormalities in decreasing order were PIK3CA (n = 5, 4.6%), EGFR (n = 3, 2.8%), KRAS (n = 2, 1.9%), ALK (n = 1, 0.9%), and RET (n = 1, 0.9%). No ROS1, BRAF, NRAS, or HER2 mutation was detected. The frequencies of gene aberrations were 15.4%, 6.8%, and 8.3% in PLCNC, SCLC, and carcinoid, respectively. Survival differences existed among PLCNC, SCLC, and carcinoid groups (37.0 vs. 34.0 vs. not reached, P = .035); however, no difference existed between PLCNC and SCLC groups (P = .606).

CONCLUSIONS

Genomic abnormality is rare in patients with PNC and it is the most frequently observed in PLCNC.

Frequency of EGFR T790M mutation and multimutational profiles of rebiopsy samples from non-small cell lung cancer developing acquired resistance to EGFR tyrosine kinase inhibitors in Japanese patients

Background

The majority of non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation eventually develop resistance to EGFR tyrosine kinase inhibitors (TKIs). Minimal information exists regarding genetic alterations in rebiopsy samples from Asian NSCLC patients who develop acquired resistance to EGFR-TKIs.

Methods

We retrospectively reviewed the medical records of patients with NSCLC harboring EGFR mutations who had undergone rebiopsies after developing acquired resistance to EGFR-TKIs. We analyzed 27 practicable samples using a tumor genotyping panel to assess 23 hot-spot sites of genetic alterations in nine genes (EGFR, KRAS, BRAF, PIK3CA, NRAS, MEK1, AKT1, PTEN, and HER2), gene copy number of EGFR, MET, PIK3CA, FGFR1, and FGFR2, and ALK, ROS1, and RET fusions. Additionally, 34 samples were analyzed by commercially available EGFR mutation tests.

Results

Sixty-one patients underwent rebiopsy. Twenty-seven samples were analyzed using our tumor genotyping panel, and 34 samples were analyzed for EGFR mutations only by commercial clinical laboratories. Twenty-one patients (34 %) had EGFR T790M mutation. Using our tumor genotyping panel, MET gene copy number gain was observed in two of 27 (7 %) samples. Twenty patients received continuous treatment with EGFR-TKIs even after disease progression, and 11 of these patients had T790M mutation in rebiopsy samples. In contrast, only 10 of 41 patients who finished EGFR-TKI treatment at disease progression had T790M mutation. The frequency of T790M mutation in patients who received continuous treatment with EGFR-TKIs after disease progression was significantly higher than that in patients who finished EGFR-TKI treatment at disease progression (55 % versus 24 %, p = 0.018).

Conclusions

The frequency of T790M mutation in this study was lower than that in previous reports examining western patients. These results suggest that continuous treatment with EGFR-TKI after disease progression may enhance the frequency of EGFR T790M mutation in rebiopsy samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2902-0) contains supplementary material, which is available to authorized users.