Influence of chemotherapy on EGFR mutation status among patients with non-small-cell lung cancer

Identifying EGFR-Expressed Cells and Detecting EGFR Multi-Mutations at Single-Cell Level by Microfluidic Chip

EGFR mutations companion diagnostics have been proved to be crucial for the efficacy of tyrosine kinase inhibitor targeted cancer therapies. To uncover multiple mutations occurred in minority of EGFR-mutated cells, which may be covered by the noises from majority of un-mutated cells, is currently becoming an urgent clinical requirement. Here we present the validation of a microfluidic-chip-based method for detecting EGFR multi-mutations at single-cell level. By trapping and immunofluorescently imaging single cells in specifically designed silicon microwells, the EGFR-expressed cells were easily identified. By in situ lysing single cells, the cell lysates of EGFR-expressed cells were retrieved without cross-contamination. Benefited from excluding the noise from cells without EGFR expression, the simple and cost-effective Sanger's sequencing, but not the expensive deep sequencing of the whole cell population, was used to discover multi-mutations. We verified the new method with precisely discovering three most important EGFR drug-related mutations from a sample in which EGFR-mutated cells only account for a small percentage of whole cell population. The microfluidic chip is capable of discovering not only the existence of specific EGFR multi-mutations, but also other valuable single-cell-level information: on which specific cells the mutations occurred, or whether different mutations coexist on the same cells. This microfluidic chip constitutes a promising method to promote simple and cost-effective Sanger's sequencing to be a routine test before performing targeted cancer therapy.

Discovery of targetable genetic alterations in advanced non-small cell lung cancer using a next-generation sequencing-based circulating tumor DNA assay

Next-generation sequencing (NGS)-based circulating tumor DNA (ctDNA) assays have provided a new method of identifying tumor-driving genes in patients with advanced non-small cell lung carcinoma (NSCLC), especially in those whose cancer tissues are unavailable or in those that have acquired treatment resistance. Here, we describe a total of 119 patients with advanced EGFR-TKI-naive NSCLC and 15 EGFR-TKI-resistant patients to identify somatic SNVs, small indels, CNVs and gene fusions in 508 tumor-related genes. Somatic ctDNA mutations were detected in 82.8% (111/134) of patients in the total cohort. Of the 119 patients with advanced NSCLC, 27.7% (33/119) were suitable for treatment with National Comprehensive Cancer Network (NCCN) guideline-approved targeted drugs. Actionable genetic alterations included 25 EGFR mutations, 5 BRAF mutations, and 1 MET mutation, as well as 1 EML4-ALK gene fusion and 1 KIF5B-RET gene fusion. In 19.3% (23/119) of the patients, we also identified genomic alterations with that could be targeted by agents that are in clinical trials, such as mTOR inhibitors, PARP inhibitors, and CDK4/6 inhibitors. Additionally, the EGFR T790M mutation was found in 46.7% (7/15) of the patients with EGFR-TKI-resistant NSCLC, suggesting that the NGS-based ctDNA assay might be an optional method to monitor EGFR-TKI resistance and to discover mechanisms of drug resistance.

Major challenges related to tumor biological characteristics in accurate mutation detection of colorectal cancer by next-generation sequencing

Next-generation sequencing (NGS) has been used in mutation detection of colorectal cancer (CRC). We here interrogated 747 CRC samples to detect mutations in 22 cancer-related genes by using NGS, and to explore some key challenges related to tumor biology. RAS mutations (KRAS or NRAS mutations), RAS/BRAF/PIK3CA mutations (mutations in KRAS, NRAS, BRAF or PIK3CA) and mutation burden (mutations in any of the 22 detected genes) were observed in 53.0% (396/747), 57.1% (431/747) and 84.2% (629/747) of specimens, respectively. Higher mutation frequencies were observed in biopsy specimens with ≥20% tumor cellularity than those with <20% tumor cellularity, but these differences were not observed in resection samples. Intratumor mutational heterogeneity was estimated by mutant allele frequency and tumor cellularity, and more likely to occur in PIK3CA mutant tumors. No significant differences of mutation frequencies were detected between primary and metastatic tumors. Additionally, specimens after chemotherapy showed lower mutation frequencies compared with specimens without chemotherapy. Together, our findings demonstrate that poor tumor cellularity, tumor heterogeneity and adjuvant therapy may confound the molecular diagnosis of CRC, and should be highlighted with prospective quality assessment during tissue process.

Adjuvant Therapy of Resected Non-small Cell Lung Cancer: can We Move Forward?

OPINION STATEMENT

Twenty years ago, an individual patient data meta-analysis of eight cisplatin-based adjuvant chemotherapy (AC) studies in completely resected early stage non-small cell lung cancer (NSCLC) demonstrated a 13 % reduction of the risk of death favoring chemotherapy that was of borderline statistical significance (p = 0.08). This marginal benefit boosted a new generation of randomized trials to evaluate the role of modern platinum-based regimens in resectable stages of NSCLC and, although individual studies generated conflicting results, overall they contributed to confirm the role of AC which is now recommended for completely resected stage II and III NSCLC, mostly 4 cycles, while subset analyses suggested a benefit in patients with large IB tumors. Cisplatin-based therapy was the core regimen of those adjuvant clinical trials and even if a substitution with other platinum-derived was also suggested, mainly based on extrapolated data from studies in advanced disease, cisplatin was confirmed to be slightly superior to carboplatin and is still the drug of choice in the adjuvant setting. Currently, any attempt to improve efficacy of cisplatin-based chemotherapy through antiangiogenic drugs association or pharmacogenomics approaches have failed, while results of additional studies are eagerly awaited. In the context of promising targeted therapies, even if several randomized trials in the advanced setting evaluated tyrosine kinase inhibitors (TKis) versus platinum-based chemotherapy and showed impressive results, clinical experience with TKIs in the adjuvant setting is still limited and most of the trials have not required patients to be molecularly tested for the drug-specific molecular predictive factor. At the present time, the role of targeted agents as adjuvant approaches remains largely not investigated. Finally, with the negative experience of the use of vaccines in this setting, the integration of immunotherapy (mainly immunocheckpoint inhibitors) in platinum-based schedules has just started to be evaluated, representing a potential future clinical option, but still far from clinical practice.

Erlotinib Salvage Therapy in Pulmonary Adenocarcinoma Patients With Disease Progression After Previous EGFR-TKI Treatment

BACKGROUND

Erlotinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) with promising efficacy in treating pulmonary adenocarcinoma. Treatment choices are few when patients with pulmonary adenocarcinoma have failed both EGFR-TKI and chemotherapy. The purpose of this study was to demonstrate the efficacy of erlotinib as salvage treatment for these nonresponsive patients.

METHODS

We retrospectively reviewed the chart records of our stage IV pulmonary adenocarcinoma patients who were diagnosed and treated between July 2004 and June 2013. Clinical data, including type of response to treatment, time to disease progression, duration between the end of first-line EGFR-TKI treatment and starting erlotinib treatment, and overall survival time, were collected.

RESULTS

A total of 98 patients were enrolled, and all had been treated with EGFR-TKI, either as a first-line therapy or following platinum-based chemotherapy; of them, 60 patients had a response to initial EGFR-TKI treatment. All received erlotinib as salvage treatment after their disease had progressed following EGFR-TKI treatment. Ninety-three (93.3%) patients had also received previous platinum-based chemotherapy. The median progression-free survival with erlotinib as salvage treatment for patients with and without a response to front-line EGFR-TKI was 4.9 and 3.4 months (P=0.869), respectively. The progression-free survival with erlotinib treatment in the sensitizing EGFR mutation group was 4.3 months, and in the EGFR wild-type group it was 2.6 months (P=0.22).

CONCLUSIONS

In pulmonary adenocarcinoma patients who had been heavily treated, erlotinib could still be a choice, regardless of the EGFR mutation status, or whether the patients had responded to previous EGFR-TKI treatment.

Treatment outcome comparisons between exons 19 and 21 EGFR mutations for non-small-cell lung cancer patients with malignant pleural effusion after first-line and second-line tyrosine kinase inhibitors

Recent studies demonstrated a significantly increased frequency of epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC) patients with malignant pleural effusions (MPEs). The purpose of this study is to investigate the effect of first-line and second-line EGFR-tyrosine kinase inhibitors (TKIs) in the treatment of NSCLC with MPEs harboring exon 19 deletion and L858R mutation. From 2010 to 2015, 203 NSCLC patients with MPEs harboring EGFR mutation treated with EGFR-TKIs were reviewed. The efficacy were evaluated with Pearson chi-square or Fisher's exact tests, Log-rank test and Cox proportional hazards model. The objective response rate (ORR) and disease control rate (DCR) for patients treated with first-line and second-line EGFR-TKIs were 21.9%, 91.4% and 14.7%, 85.3%, respectively. The overall median PFS and OS of enrolled NSCLC patients with MPE were 9.3 months (95% CI, 8.4-10.2 months), 20.9 months (95% CI, 18.9-22.9 months) after first-line TKIs, and 7.6 months (95% CI, 6.6-8.6 months), 15.3 months (95% CI, 13.6-15.9 months) after second-line TKIs. The exon 19 deletion arm had a longer median PFS (9.4 vs 7.1 months, p=0.003) and OS (16.8 vs 13.8 months, p=0.003) compared with the L858R mutation arm after second-line TKIs. In a conclusion, EGFR genotype was an independent predictor of PFS and OS. No significant side effects differences between the two mutation groups was observed for first or second-line EGFR-TKIs. This study demonstrated that EGFR mutations are significant predictors for advanced NSCLC patients with MPE receiving second-line EGFR-TKIs treatment.

Establishment and characterization of 6 novel patient-derived primary pancreatic ductal adenocarcinoma cell lines from Korean pancreatic cancer patients

BACKGROUND

Pancreatic ductal adenocarcinomas are among the most malignant neoplasms and have very poor prognosis. Our understanding of various cancers has recently improved the survival of patients with cancer, except for pancreatic cancers. Establishment of primary cancer cell lines of pancreatic ductal adenocarcinomas will be useful for understanding the molecular mechanisms of this disease.

METHODS

Eighty-one surgically resected pancreatic ductal adenocarcinomas were collected. Six novel pancreatic cancer cell lines, AMCPAC01-06, were established and histogenetic characteristics were compared with their matched tissues. The clinicopathologic and molecular characteristics of the cell lines were investigated by KRAS and TP53 sequencing or SMAD4 and p53 immunohistochemistry. Xenografts using AMCPAC cell lines were established.

RESULTS

From the 81 pancreatic ductal adenocarcinomas, six (7.4% success rate) patient-derived primary cell lines were established. The six AMCPAC cell lines showed various morphologies and exhibited a wide range of doubling times. AMCPAC cell lines contained mutant KRAS in codons 12, 13, or 61 and TP53 in exon 5 as well as showed aberrant p53 (5 overexpression and 1 total loss) or DPC4 (all 6 intact) expression. AMCPAC cell lines demonstrated homology for the KRAS mutation and p53 expression compared with matched primary cancer tissues, but showed heterogeneous DPC4 expression patterns.

CONCLUSIONS

The novel AMCPAC01-06 cell lines established in this study may contribute to the understanding of pancreatic ductal adenocarcinomas. Trial registration Retrospectively registered.

Altered status of programmed death-ligand 1 after recurrence in resected lung adenocarcinoma patients

Purpose

Programmed death-ligand 1 (PD-L1) is found to be overexpressed in non-small cell lung cancer. The present study intended to evaluate the status of PD-L1 expression in patients with resection and recurrent lung adenocarcinoma.

Patients and methods

Matched resection and recurrent tumor samples were harvested from 65 lung adenocarcinoma patients. Immunohistochemistry was used to evaluate the status of PD-L1 expression. Kaplan–Meier method was used for survival analysis.

Results

A total of 65 patients of lung adenocarcinoma were enrolled. They underwent complete resection and had recurrence after adjuvant treatment. PD-L1 expression was identified in 43.1% (28/65) of resection samples vs 55.4% (36/65) of recurrent samples. Ten patients shifted from negative to positive, whereas another two samples showed the opposite. Patients with PD-L1 expression showed worse disease-free survival than the PD-L1-negative counterparts. The expression of PD-L1 in recurrent samples was a significant favorable factor for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) (11.2 vs 8.2 months, P=0.030).

Conclusion

The status of PD-L1 expression may alter between resection and recurrent samples. Also, the status of PD-L1 expression after recurrence is a better prognostic factor for EGFR-TKIs.

Post surgery circulating free tumor DNA is a predictive biomarker for relapse of lung cancer

Cancer cells release DNA fragments into plasma as circulating free DNA (cfDNA). However, quantitative measurement of tumor-derived DNA in cfDNA remains challenge. The purpose of this study was to quantitatively assess tumor-derived DNA in lung cancer patients. By optimizing competitive allele-specific TaqMan PCR (CAST-PCR), we assessed the copy number of mutated Kirsten rat sarcoma viral oncogene homolog (KRAS) and epidermal growth factor receptor (EGFR) alleles in the pre/post surgery plasma of 168 lung cancer patients. An absolute quantitative PCR method was developed to assess the number of total cfDNA. All mutations detected in tumors were also found in the plasma after surgery. At the time of 30 days after surgery, EGFR mutation of circulating cell-free DNA was detected only in two patients who recurred in 4 months after surgery. Compared to that of normal control at 30 days after surgery, five patients who recurred in 4 months had significantly higher circulating cell-free DNA (P < 0.001), whereas six patients who recurred after 4 months (P = 0.207) and five patients without recurrence (P = 0.901) demonstrated significantly lower circulating cell-free DNA. Our findings suggest that cfDNA analysis in plasma is an alternative and supplement to tissue analysis and hold promise for clinical application. Stratification of patients according to cfDNA levels at 30 days after surgery might be helpful in selecting lung cancer patients for adjuvant therapy after surgery.

Cross-Platform Comparison of Four Leading Technologies for Detecting EGFR Mutations in Circulating Tumor DNA from Non-Small Cell Lung Carcinoma Patient Plasma

Analysis of circulating tumor DNA (ctDNA) is emerging as a powerful tool for guiding targeted therapy and monitoring tumor evolution in patients with non-small cell lung cancer (NSCLC), especially when representative tissue biopsies are not available. Here, we have compared the ability of four leading technology platforms to detect epidermal growth factor receptor (EGFR) mutations (L858R, exon 19 deletion, T790M and G719X) in ctDNA from NSCLC patients. Two amplification refractory mutation systems (cobas-ARMS and ADx-ARMS), a droplet digital polymerase chain reaction (ddPCR) and a next-generation sequencing (Firefly NGS) platform were included in the comparison. Fifteen EGFR mutations across twenty NSCLC patients were identified. Firefly NGS, cobas-ARMS and ddPCR all displayed superior sensitivity while ADx-ARMS was better suited for the qualitative detection of EGFR mutations with allele frequency higher than 1% in plasma and tissue samples. We observed high coincidence between the plasma and tissue EGFR mutational profiles for three driver mutations (L858R, exon 19 deletion and G719X) that are known targets of first generation EGFR-TKI therapies among patients who relapsed. Discrepancies between tissue and plasma EGFR mutational profiles were mainly attributable to spatial and temporal tumor heterogeneity, mutation inhibition due to therapy response and drug resistance (T790M). This study illustrates the challenges associated with selection of a technology platform for EGFR ctDNA analysis in the context of treatment evaluation and drug resistance detection.

Circulating Tumor DNA as Biomarkers for Cancer Detection

Detection of circulating tumor DNAs (ctDNAs) in cancer patients is an important component of cancer precision medicine ctDNAs. Compared to the traditional physical and biochemical methods, blood-based ctDNA detection offers a non-invasive and easily accessible way for cancer diagnosis, prognostic determination, and guidance for treatment. While studies on this topic are currently underway, clinical translation of ctDNA detection in various types of cancers has been attracting much attention, due to the great potential of ctDNA as blood-based biomarkers for early diagnosis and treatment of cancers. ctDNAs are detected and tracked primarily based on tumor-related genetic and epigenetic alterations. In this article, we reviewed the available studies on ctDNA detection and described the representative methods. We also discussed the current understanding of ctDNAs in cancer patients and their availability as potential biomarkers for clinical purposes. Considering the progress made and challenges involved in accurate detection of specific cell-free nucleic acids, ctDNAs hold promise to serve as biomarkers for cancer patients, and further validation is needed prior to their broad clinical use.

Epidermal growth factor receptor T790M mutation-positive metastatic non-small-cell lung cancer: focus on osimertinib (AZD9291)

Adenocarcinoma is the most common type of non-small-cell lung cancer (NSCLC). Adenocarcinoma with epidermal growth factor receptor (EGFR) mutations accounts for 8%–30% of all cases of NSCLC depending on the geography and ethnicity. EGFR-mutated NSCLC usually responds to first-line therapy with EGFR tyrosine kinase inhibitors (TKIs). However, there is eventual loss of efficacy to TKIs due to development of resistance. The most frequent cause for resistance is a second EGFR mutation in exon 20 (T790M), which is encountered in up to 62% of patients. Osimertinib is one of the third-generation EGFR TKIs with a high selective potency against T790M mutants. In Phase I trial of osimertinib in advanced lung cancer after progression on EGFR TKIs, the response rate and disease control rate were 61% and 95%, respectively. A subsequent Phase II (AURA2) trial demonstrated a disease control rate of 92%, a response rate of 71%, a median duration of response of 7.8 months, and a median progression-free survival of 8.6 months. Osimertinib was approved by the US Food & Drug Administration in November 2015 for patients whose tumors exhibited T790M mutation and for those with progressive disease on other EGFR TKIs. In this review, we address the role of EGFR TKIs in the management of EGFR mutation lung cancer and the mechanisms of resistance to TKIs with a focus on the role of osimertinib. Data from completed trials of osimertinib, ongoing trials, as well as novel diagnostic methods to detect EGFR T790M mutation are reviewed.

Efficacy of Second-line Tyrosine Kinase Inhibitors in the Treatment of Metastatic Advanced Non-small-cell Lung Cancer Harboring Exon 19 and 21 EGFR Mutations

Background: Although superior clinical benefits of first-line epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in the treatment of advanced non-small-cell lung cancer (NSCLC) had been reported with different sensitivity, the sensitivity of second-line TKIs in NSCLC patients with different EFGR mutations was unknown. The purpose of this study is to investigate the clinical outcome of second-line EGFR-TKIs in the treatment of NSCLC patients according to different EGFR genotypes.

Methods: The treatment outcomes of 166 NSCLC patients with different EGFR mutations treated by second-line TKIs were retrospectively reviewed. The efficacy was evaluated with Pearson chi-square or Fisher's exact tests, Log-rank test and Cox proportional hazards model.

Results: The disease control rate (DCR) and objective response rate (ORR) of enrolled NSCLC patients were 77.7% and 11.4%, respectively. The exon 19 deletion group had a significantly longer median progression-free survival (PFS) (6.7 vs. 4.5 months, P=0.002) and overall survival (OS) (13.7 vs. 11.7 months, P=0.02) compared with the exon 19 L858R mutation group for NSCLC patients, as well for patients with brain metastasis [PFS: (6.7 vs. 3.9 months, p<0.001), OS: (13.7 vs. 7.9 months, p=0.006)]. No significant difference on PFS and OS was observed between exon 19 deletion and L858R mutation group for patients with bone metastasis. EGFR genotype and ECOG PS were independent predictors of PFS. Never smoking, exon 19 deletion, EGOC PS (0-1) and no brain metastasis were correlated with longer OS. No significant difference on side effect between exon 19 and 21 mutation group was observed.

Conclusions: NSCLC patients harboring exon 19 deletion achieved better PFS and OS than those with L858R mutation, indicating that EGFR mutation is a significant prognostic factor for advanced NSCLC patients with and without brain metastasis receiving second-line EGFR-TKIs treatment.

Analysis of EGFR mutation status in tissue and plasma for predicting response to EGFR-TKIs in advanced non-small-cell lung cancer

The detection of mutations in the epidermal growth factor receptor (EGFR) gene in tumor tissues has been established as the gold standard for predicting the efficacy of treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) in advanced non-small-cell lung cancer (NSCLC). The current study aimed to investigate whether the presence of co-existing EGFR mutations in tumor tissue and in cell-free tumor DNA (ctDNA) in the plasma predicts a more favorable outcome of EGFR-TKI treatment in advanced NSCLC. A total of 287 NSCLC patients who had undergone EGFR-TKI treatment were enrolled and stratified into four subgroups: Wild-type EGFR in plasma and tissue specimens (B-/T-); mutated EGFR in plasma and tissue specimens (B+/T+); mutated EGFR in only in plasma samples (B+/T-); or mutated EGFR in only tissue specimens (B-/T+). EGFR mutations were tested using denaturing high-performance liquid chromatography and confirmed by amplification-refractory mutation system analysis. Of the 287 patients, 101 had mutations in both tissue and plasma samples and 103 had mutation in either tissue (n=65) or plasma (n=38). The median progression-free survival (mPFS) times were 9.2 and 2.0 months in the B+/T+ and B-/T- groups, respectively. The mPFS times were 7.9 months in the B-/T+ group and 11.9 months in the B+/T-group (P=0.001). Among the 187 patients with available pre-EGFR-TKI plasma samples, 70 received first-line EGFR-TKI treatment, and the mPFS in the B+/T+ group was longer than in the B-/T+ or B+/T- groups (18.8 vs. 9.4 vs. 6.9 months; P=0.003). In second-line setting of EGFR-TKI therapy, the groups of patients with EGFR mutation in ctDNA, regardless of the mutation status in the tissues, exhibited longer mPFS times compared with the B-/T+ group (10.0 vs. 5.8 months; P=0.044). The results suggest that co-existence of EGFR mutations in tissue and ctDNA predict longer PFS times for NSCLC patients who receive first-line EGFR-TKI therapy. In addition, real-time detection in ctDNA is an excellent predictor for the efficacy of second- or higher line EGFR-TKI therapy.

Treatment choice in epidermal growth factor receptor mutation-positive non-small cell lung carcinoma: latest evidence and clinical implications

Discovery of sensitizing mutations in epidermal growth factor receptor (EGFR) and the subsequent development of EGFR tyrosine kinase inhibitors (TKIs) have substantially changed the treatment of lung cancer. First-line treatment with EGFR TKIs (gefitinib, erlotinib and afatinib) has demonstrated a superior response rate and progression-free survival (PFS) compared with chemotherapy in EGFR-mutation positive patients. However, a number of open questions remain, such as choice between the three EGFR TKIs licensed, treatment of patients unsuitable for chemotherapy due to morbidity or advanced age, management of acquired resistance and optimal biological sample to determine EGFR status. Recently the first head-to-head trial comparing gefitinib and afatinib (LUX-Lung 7) has been reported. Moreover, third-generation EGFR TKIs such as osimertinib, rociletinib, olmutinib and ASP8273, with preferential activity against T790M mutant tumours, the commonest resistance mechanism to EGFR TKIs, have shown promising results in early clinical trials, with osimertinib now licensed. In this review, we summarize latest advances in the treatment of EGFR-mutation positive patients focusing on controversial areas and emerging challenges to optimally treat these patients in the future.

Efficacy of chemotherapy in epidermal growth factor receptor (EGFR) mutated metastatic pulmonary adenocarcinoma patients who had acquired resistance to first-line EGFR tyrosine kinase inhibitor (TKI)

INTRODUCTION

Salvage chemotherapy is frequently used when tumour epidermal growth factor receptor (EGFR) mutated patients experience disease progression with first-line EGFR-tyrosine kinase inhibitor (TKI) treatment. However, the efficacy of salvage chemotherapy is still unknown.

METHODS

We retrospectively reviewed the chart records of our pulmonary adenocarcinoma patients between 2010 and 2013.

RESULTS

Five hundred and six of the 1240 stage IV adenocarcinoma patients had an EGFR mutation and 338 received first-line EGFR-TKI treatment. In all, 169 patients in this group received salvage chemotherapy after failure of EGFR-TKI, and 102 patients were eligible for this study. The chemotherapy response rate of these 102 patients was 24.5%, with a median progression-free survival (PFS) of 4.5?months, and median survival time was 14.6?months. Patients who received pemetrexed-based chemotherapy had longer PFS and overall survival (OS), although the extent was statistically insignificant. Progression-free survival and OS were longer for patients who received combination chemotherapy than single-agent chemotherapy.

CONCLUSIONS

Pemetrexed-based combination chemotherapy is preferred before a more efficient treatment strategy is found.

Targeted Therapy Management in NSCLC Patients Using Cytology: Experience from a Tertiary Care Cancer Center

BACKGROUND

Although biopsy is the gold standard for diagnosis, cytological material has often been used to assist in making a pathologic diagnosis as well as for molecular testing in certain cancers such as in the lung, cervix, and head/neck.

OBJECTIVE

Our objective is to share experience from our institution in the use of cytological material in screening for epidermal growth factor receptor (EGFR) mutations in a subset of patients with non-small cell lung cancer (NSCLC).

METHODS

Fine needle aspirates, pleural effusion, cell blocks of 223 NSCLC patients, where cytology suggested malignancy were screened for EGFR mutation in exons 18-21 using Scorpion(®) ARMS real-time polymerase chain reaction (PCR) technology.

RESULTS

Overall, EGFR mutation was seen in 43.5 % of study samples. Deletions were highest in exon 19 (27.2 %), followed by exon 21 (15.5 %), exon 18 (5.3 %), and exon 20 (1.9 %). Chi-squared analysis revealed a significant correlation for mutation status in women compared with men (χ (2) = 5.88, p = 0.02), with exon 19 mutation predominating (χ (2) = 5.66, p = 0.02).

CONCLUSION

Our results demonstrate the successful use of cytology material for molecular testing in a subset of NSCLC patients to direct their treatment.

Understanding Mechanisms of Resistance in the Epithelial Growth Factor Receptor in Non-Small Cell Lung Cancer and the Role of Biopsy at Progression

Molecular profiling and the discovery of drugs that target specific activating mutations have allowed the personalization of treatment for non-small cell lung cancer (NSCLC). The epithelial growth factor receptor (EGFR) is frequently over-expressed and/or aberrantly activated in different cancers, including NSCLC. The most common activating mutations of EGFR in NSCLC fall within the tyrosine kinase-binding domain. Three oral EGFR tyrosine kinase inhibitors (TKIs) have been approved by the U.S. Food and Drug Administration (FDA) for first-line use in patients with EGFR mutation-positive NSCLC (exon 19 deletions or exon 21 [L858R] substitution mutations), as detected by an FDA-approved test. However, disease progression is common and is often the result of secondary mutations, of which the EGFR T790M mutation is the most prevalent. Few options were available upon progression until the introduction of osimertinib, a kinase inhibitor that targets the T790M mutation, which was recently approved for use in patients with metastatic EGFR T790M mutation-positive NSCLC, as detected by an FDA-approved test, who progressed on or after EGFR TKI therapy. With the introduction of osimertinib, outcomes can now be improved in select patients. Therefore, performing a biopsy at progression to determine the underlying molecular cause of the acquired resistance is important for the enabling of individualized options that may provide the greatest opportunity for improved outcomes. This review discusses the latest updates in molecular testing at progression and outlines treatment options for this difficult-to-treat population.

THE ONCOLOGIST

2017;22:3-11 IMPLICATIONS FOR PRACTICE: Although the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs)-gefitinib, erlotinib, and afatinib-have changed the treatment paradigm for non-small cell lung cancer among those with EGFR mutation positive disease, most patients experience progression after approximately 12 months of treatment. Until recently, options were limited for patients who progressed, but improvements in molecular profiling and the approval of osimertinib, which targets the resistance mutation T790M, afford the opportunity for improved outcomes in many patients with this mutation. This article explains the options available after progression on initial EGFR TKI therapy and the importance of molecular testing at progression in making treatment decisions.

Comparison of Epidermal Growth Factor Receptor Mutations between Metastatic Lymph Node Diagnosed by EBUS-TBNA and Primary Tumor in Non-Small Cell Lung Cancer

Introduction

Although the use of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is increasing for epidermal growth factor receptor (EGFR) testing in lung cancer, the discordance rate in EGFR mutations between lymph node (LN) samples obtained by EBUS-TBNA and primary tumor (PT) is not well known. Thus, we compared the EGFR mutation status of LN samples obtained by EBUS-TBNA and PTs to estimate the efficacy of using EBUS-TBNA specimens for EGFR testing in advanced, non-squamous, non-small cell lung cancer (NSCLC).

Materials and Methods

Using data of patients from the EBUS-TBNA database (N = 1914) obtained between January 2009 and January 2013, we identified 100 treatment-naïve, advanced, non-squamous NSCLC patients (stage 3 and 4) with matched LN specimens obtained by EBUS-TBNA and PT specimens. Of these, 74 patients with paired specimens were feasible for EGFR mutation analysis, which we performed using a direct sequencing method.

Results

Of the 74 cases, at least one major [exon 19 deleted (19del) and L858R] or minor (T790M, exon 20 insertion, and other point mutations) EGFR mutation was detected in 31 cases (41.9%), which included PT (n = 31, 41.9%) and LN (n = 28, 37.8%) specimens. Major mutations were detected in 25 PT (33.8%, 19del = 13, L858R = 12) and 22 LN (29.8%, 19del = 11, L858R = 11) specimens. The discordance rate in major mutations between matched PT and LN specimens was 4.1% (3/74). Among minor mutations, T790M was detected in LN specimen only in 2 cases with L858R in PT and LN. The discordance rate major and minor EGFR mutations combined between matched PT and LN specimens was 12% (9/74).

Conclusions

We observed a high concordance rate of major EGFR mutations between matched LN specimens sampled by EBUS-TBNA and PTs, suggesting that LN samples obtained by EBUS-TBNA from advanced non-squamous NSCLC patients are effective for use in EGFR mutation testing.

Radiomics and its emerging role in lung cancer research, imaging biomarkers and clinical management: State of the art

With the development of functional imaging modalities we now have the ability to study the microenvironment of lung cancer and its genomic instability. Radiomics is defined as the use of automated or semi-automated post-processing and analysis of large amounts of quantitative imaging features that can be derived from medical images. The automated generation of these analytical features helps to quantify a number of variables in the imaging assessment of lung malignancy. These imaging features include: tumor spatial complexity, elucidation of the tumor genomic heterogeneity and composition, subregional identification in terms of tumor viability or aggressiveness, and response to chemotherapy and/or radiation. Therefore, a radiomic approach can help to reveal unique information about tumor behavior. Currently available radiomic features can be divided into four major classes: (a) morphological, (b) statistical, (c) regional, and (d) model-based. Each category yields quantitative parameters that reflect specific aspects of a tumor. The major challenge is to integrate radiomic data with clinical, pathological, and genomic information to decode the different types of tissue biology. There are many currently available radiomic studies on lung cancer for which there is a need to summarize the current state of the art.

A decade of EGFR inhibition in EGFR-mutated non small cell lung cancer (NSCLC): Old successes and future perspectives

The discovery of Epidermal Growth Factor Receptor (EGFR) mutations in Non Small Cell Lung Cancer (NSCLC) launched the era of personalized medicine in advanced NSCLC, leading to a dramatic shift in the therapeutic landscape of this disease. After ten years from the individuation of activating mutations in the tyrosine kinase domain of the EGFR in NSCLC patients responding to the EGFR tyrosine kinase inhibitor (TKI) Gefitinib, several progresses have been done and first line treatment with EGFR TKIs is a firmly established option in advanced EGFR-mutated NSCLC patients. During the last decade, different EGFR TKIs have been developed and three inhibitors have been approved so far in these selected patients. However, despite great breakthroughs have been made, treatment of these molecularly selected patients poses novel therapeutic challenges, such as emerging of acquired resistance, brain metastases development or the need to translate these treatments in earlier clinical settings, such as adjuvant therapy.

The aim of this paper is to provide a comprehensive review of the major progresses reported so far in the EGFR inhibition in this molecularly-selected subgroup of NSCLC patients, from the early successes with first generation EGFR TKIs, Erlotinib and Gefitinib, to the novel irreversible and mutant-selective inhibitors and ultimately the emerging challenges that we, in the next future, are called to deal with.

Comparing overall survival between first generation EGFR-TKIs and chemotherapy in lung cancer patients with Del19/L858R

Objective

Combined overall survival (OS) analysis of Lux-Lung 3 and Lux-Lung 6 demonstrated that patients with epidermal growth factor receptor (EGFR) exon 19 deletions (Del19) would benefit from first-line second generation EGFR tyrosine kinase inhibitors (TKIs) afatinib but not for those with L858R. This study was to investigate the survival difference between first-line first generation EGFR-TKIs and chemotherapy in patients with either Del19 or L858R, and to directly compare OS in these two mutation groups.

Methods

Eligibles were all prospective and retrospective studies comparing EGFR-TKIs with conventional chemotherapy or receiving single agent EGFR-TKIs and demonstrating survival analysis based on mutation types. The primary outcome was OS measured as pooled hazard ratios (HRs). All measures were pooled using randomeffects models and 95% confidential interval (95% CI) was calculated.

Results

A total of 14 studies incorporating 1,706 patients with either Del19 or L858R were included. Enrolling patients with Del19 or L858R in randomized controlled trials (RCTs), first-line first generation EGFR-TKIs were associated with no OS benefit, compared with chemotherapy (pooled HR_TKI/Chemo for Del19: 0.82, 95% CI: 0.64-1.06, P = 0.14; pooled HR_TKI/Chemo for L858R: 1.15, 95% CI: 0.85-1.56, P = 0.38). Direct comparison of Del19 with L858R receiving with first-line first generation EGFR-TKIs demonstrated no significant survival difference (pooled HR19/21: 0.88, 95% CI: 0.67-1.16, P = 0.37).

Conclusions

Among patients with advanced non-small cell lung cancer (NSCLC) harboring Del19 and L858R, first-line first generation EGFR-TKIs demonstrated no survival benefit comparing with chemotherapy. Direct comparison between Del19 and L858R revealed no significant survival difference after first-line first generation EGFR-TKIs.

A heterochronic genetic change from an EGFR mutation to an ALK rearrangement in a patient with lung adenocarcinoma: a case report

An 87-year-old man with postoperative recurrent lung adenocarcinoma was treated with gefitinib. At the beginning of treatment, surgically resected archived tumor tissue revealed a deletion in exon 19 of the EGFR gene, but no ALK gene rearrangement. After gefitinib treatment for 9 months, the disease progressed. Bronchoscopic rebiopsy was used to evaluate resistance mechanisms, and revealed lung adenocarcinoma with wild-type EGFR genes and a newly emerged ALK gene rearrangement. Treatment was switched to alectinib and a partial response was achieved within 4 weeks. This is a rare case of heterochronic genetic change to an ALK gene rearrangement in EGFR mutant lung adenocarcinoma.

Malignant pleural effusion cell blocks are substitutes for tissue in EML4-ALK rearrangement detection in patients with advanced non-small-cell lung cancer

OBJECTIVE

To evaluate the feasibility of malignant pleural effusions (MPE) as surrogate samples for the detection of echinoderm microtubule-associated protein-like4 (EML4)-anaplastic lymphoma kinase (ALK) and to investigate the prognostic and predictive value of EML4-ALK in MPE of non-small-cell lung cancer (NSCLC).

METHODS

One hundred and nine NSCLC patients were retrospectively analysed. EML4-ALK was identified using paraffin-embedded tumour cells in MPE samples by immunohistochemistry (IHC, Ventana) and confirmed by fluorescence using in situ hybridisation (FISH) and qRT-PCR. The EGFR mutation was determined by MPE, using denaturing high-performance liquid chromatography (DHPLC).

RESULTS

A total of 5 out of 109 (4.58%) patients were identified as EML4-ALK rearrangement in MPE by IHC.; In addition to two metachronous samples, the consistency of MPE and tissue for EML4-ALK detection was 100% (21/21), and the sensitivity and specificity were 100% (2/2) and 100% (19/19), respectively. EML4-ALK rearrangement cases were confirmed by FISH and qRT-PCR; the sensitivity were both 100% (2/2) when compared with tissue, and it was 60% (3/5) and 100% (5/5), respectively, when compared with MPE by IHC. The overall response rate (ORR) was 100% (2/2) for patients with EML4-ALK in MPE. Moreover, the PFS of these patients appeared to be prolonged in chemotherapy (9.27 versus 6.53 and versus 4.67 months, P = 0.122), compared with the EGFR mutation and the EGFR/ALK double negative group, respectively.

CONCLUSION

EML4-ALK rearrangement detection in malignant pleural effusions is a complementary method for EML4-ALK detection. VETANA and qRT-PCR are more appropriate for MPE detection. EML4-ALK rearrangement in pleural effusions has a predictive value for treatment.

Micropapillary: A component more likely to harbour heterogeneous EGFR mutations in lung adenocarcinomas

The micropapillary (MP) subtype has recently been established to be a distinct marker of poor prognosis in lung adenocarcinomas (LACs). According to the 2015 WHO classification system, LAC constituents are required to be precisely reported. T790M mutation and an insertion in exon 20 (E20ins) are associated with EGFR-TKI resistance. A total of 211 LAC patients were involved in this study, and EGFR mutations were determined using an amplification refractory mutation system (ARMS). Sex, smoking history, lymph node status, and clinical stage differed significantly between the EGFR wild type and mutant groups (p < 0.05). The EGFR mutation occurred more frequently in female, non-smokers, ACs with papillary (85.7%) or MP components (91.4%) (p < 0.001). Twenty ACs with naïve T790M or E20ins were microdissected. The AC constituents metastasizing to lymph nodes exhibited a phenotype and EGFR status that was consistent with the primary loci constituents. Glomerulus-like solid components exhibited the same EGFR status as the surrounding T790M-mutated MP components. The MP and glomerulus-like portions in AC tumours exhibited a congenial EGFR status, but the acinar cells with papillary cells were heterogeneous. The naïve T790M mutants, although minor in the MP component, dramatically increased after EGFR-TKI therapy and indicate that the MP components feature intrinsic heterogeneity.

EGFR-tyrosine kinase inhibitor treatment in a patient with advanced non-small cell lung cancer and concurrent exon 19 and 21 EGFR mutations: A case report and review of the literature

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are considered to be effective treatments for advanced non-small cell lung cancer (NSCLC) patients with sensitizing EGFR mutations, including exon 19 deletion and exon 21 L858R mutations. However, with the development of EGFR mutation detection assays, patients with complex EGFR mutations are emerging, and their response to EGFR-TKIs remains unclear. The present study reports a case of a 62-year-old, non-smoking female patient with advanced NSCLC, presenting with concurrent EGFR 19+21 sensitizing mutations, who had a poor response to the first-line EGFR-TKI erlotinib and succumbed 5 months subsequent to diagnosis. Furthermore, the present study performed a literature review, and 18 patients with complex EGFR 19+21 mutations that had received EGFR-TKIs were identified. The majority of these patients responded well to EGFR-TKIs. To the best of our knowledge, the present case is the first to report a patient with lung adenocarcinoma with complex EGFR 19+21 sensitizing mutations that had a poor clinical response to a first-line EGFR-TKI. Despite the 70% response rate of sensitizing EGFR-mutant NSCLCs to EGFR-TKIs, there is still a proportion of patients that experience de novo resistance, and heterogeneity is likely to be important in this resistance mechanism. Therefore, comprehensive genomic detection assays and multi-targeted therapies for patients with NSCLC with complex EGFR mutations require additional investigation.

Overcoming drug resistance to receptor tyrosine kinase inhibitors: Learning from lung cancer

There are various receptor tyrosine kinase (TK)-targeted drugs that are currently used in the treatment of patients with non-small cell lung cancer (NSCLC). Among them, the epidermal growth factor receptor (EGFR) TK inhibitors (TKIs) are the most extensively studied. Receptor TKIs including EGFR TKIs have shown dramatic therapeutic efficacies in malignant tumors, which harbor activating mutations in the EGFR gene. However, within 1 or 2years after treatment, patients harboring these mutations often develop resistance to TKI therapy. This review article is aimed at drawing attention to the fact that we must first understand how receptor TKI resistance is acquired to develop strategies for overcoming resistance to TKIs. Furthermore, an insight into the specific molecules or signaling pathways that mediate resistance is a key factor for understanding and overcoming acquired drug resistance. Finally, we present our views on the continuing battle against "drug resistance," and provide further guidelines and strategies on how to minimize the development of drug-resistant tumors.

Autoimmune response to PARP and BRCA1/BRCA2 in cancer

Purpose

To determine the role of autoantibodies to PARP1 and BRCA1/BRCA2 which were involved in the synthetic lethal interaction in cancer.

Methods

Enzyme-Linked Immunosorbent Assay (ELISA) was used to detect autoantibodies to PARP1 and BRCA1/BRCA2 in 618 serum samples including 131 from breast cancer, 94 from lung cancer, 34 from ovarian cancer, 107 from prostate cancer, 76 from liver cancer, 41 from pancreatic cancer and 135 from normal individuals. The positive sera with ELISA were confirmed by Western blot. Immunohistochemistry was used to examine the expression of PARP1 and BRCA1/BRCA2 in breast cancer.

Results

Autoantibody frequency to PARP1, BRCA1, and BRCA2 in cancer varied from 0% to 50%. When the sera from cancer patients were tested for the presence of autoantibodies to PARP1 and BRCA1/BRCA2, the autoantibody responses slightly decreased and the positive autoantibody reactions varied from 0% to 50.0%. This was significantly higher autoantibody responses to PARP1 and BRCA1/BRCA2 (especially to PARP1 and BRCA1) in ovarian cancer and breast cancer compared to normal control sera (P < 0.001 and P < 0.01). Immunohistochemistry indicated that Pathology Grade at diagnosis to PARP1 expression in breast cancer was different (P < 0.05).

Conclusions

Different cancers have different profiles of autoantibodies. The autoantibodies to proteins involving the synthetic lethal interactions would be novel serological biomarker in some selective cancers.

Factors that predict progression-free survival in Chinese lung adenocarcinoma patients treated with epidermal growth factor receptor tyrosine kinase inhibitors

BACKGROUND

Although first-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have shown efficacy in patients with advanced lung cancers, survival predictors with these drugs have not been extensively investigated. This study was performed to explore factors that may predict progression-free survival (PFS) in Chinese lung adenocarcinoma patients treated with EGFR-TKIs.

METHODS

We retrospectively collected clinicopathologic data on 208 patients who received either gefitinib, erlotinib or icotinib, including the patients' EGFR mutation status and levels of six serum tumor markers [carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), cancer antigen 125 (CA125), squamous cell carcinoma antigen (SCC), cytokeratin-19 fragments (CYFRA21-1) and lactate dehydrogenase (LDH)]. Univariate and multivariate survival analyses were performed to identify independent prognostic factors associated with PFS.

RESULTS

At the study cutoff date, 189 (90.9%) of the patients met the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 criteria for progressive disease (PD), while 19 (9.1%) had stable disease (SD). The median PFS of the 208 patients was 12.4 months (95% CI, 11.0-13.8 months). In the multivariate analysis using a Cox proportional hazard model, a non-smoking history [hazard ratio (HR) =2.460; 95% CI, 1.484-4.079; P<0.001], first-line treatment (HR =1.500; 95% CI, 1.062-2.119; P=0.021), and a high pretreatment serum level of CEA (HR =1.424; 95% CI 1.026-1.977; P=0.035) were found to be significant predictors of a longer PFS.

CONCLUSIONS

In Chinese lung adenocarcinoma patients treated with EGFR-TKIs, a non-smoking history, first-line EGFR-TKIs treatment and a high serum level of CEA were independent predictors of a longer PFS along with an EGFR-activating mutation.

Hepatic Metastases is Associated with Poor Efficacy of Erlotinib as 2nd/3rd Line Therapy in Patients with Lung Adenocarcinoma

BACKGROUND

Hepatocyte growth factor (HGF)-mediated mesenchymal-to-epithelial transition factor (MET) gene amplification is a common mechanism for acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). MET gene amplification has also been associated with hepatic metastases in patients with lung cancer. The aim of this study was to investigate whether hepatic metastases are associated with decreased efficacy of erlotinib in patients with adenocarcinoma.

MATERIAL/METHODS

A cohort of 329 patients with stage IV lung adenocarcinoma, known EGFR mutation status, and who received treatment with erlotinib in the 2nd or 3rd line setting were enrolled into this study over a period of 4 years between January 2011 and January 2015. The cohort was stratified based on the presence or absence of hepatic metastases and the efficacy of erlotinib was defined based on disease control rate (DCR) and progression-free survival (PFS).

RESULTS

Hepatic metastases were present in 220 of the 329 enrolled lung adenocarcinoma patients. EGFR-activating mutations (exon 19 deletion or an exon 21 L858R mutation) were identified in 113 (34.3%) patients. The DCR was significantly lower in the hepatic metastases group than in patients without hepatic metastases (39.5% vs. 51.4% P=0.045). In patients with hepatic metastases, median PFS was 2.3 months in the EGFR mutation-positive group versus 1.4 months in the EGFR mutation-negative group (95% CI 1.3-3.3 vs. 1.3-1.5; P=0.055). Of note, erlotinib therapy in patients with hepatic metastases was complicated by elevated alanine transaminase (ALT) levels.

CONCLUSIONS

Hepatic metastasis in patients with lung adenocarcinoma predicts poor response to erlotinib as a 2nd/3rd line therapy. Combination therapy, for example with MET-TKI, may be a good choice for patients with liver metastases with poor prognosis.

Target Therapy in Lung Cancer

Lung cancer is an extremely heterogeneous disease, with well over 50 different histological variants recognized under the fourth revision of the World Health Organization (WHO) typing system. Because these variants have differing genetic and biological properties correct classification of lung cancer is necessary to assure that lung cancer patients receive optimum management. Due to the recent understanding that histologic typing and EGFR mutation status are important for target the therapy in lung adenocarcinoma patients there was a great need for a new classification that addresses diagnostic issues and strategic management to allow for molecular testing in small biopsy and cytology specimens. For this reason and in order to address advances in lung cancer treatment an international multidisciplinary classification was proposed by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS), further increasing the histological heterogeneity and improving the existing WHO-classification. Is now the beginning of personalized therapy era that is ideally finalized to treat each individual case of lung cancer in different way.

Circulating DNA in diagnosis and monitoring EGFR gene mutations in advanced non-small cell lung cancer

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are current treatments for advanced non-small cell lung cancer (NSCLC) harboring activating EGFR gene mutations. Histological or cytological samples are the standard tumor materials for EGFR mutation analysis. However, the accessibility of tumor samples is not always possible and satisfactory in advanced NSCLC patients. Moreover, totality of EGFR mutated NSCLC patients will develop resistance to EGFR-TKIs. Repeat biopsies to study genetic evolution as a result of therapy are difficult, invasive and may be confounded by intra-tumor heterogeneity. Thus, exploring accurate and less invasive techniques to (I) diagnosis EGFR mutation if tissue is not available or not appropriate for molecular analysis and to (II) monitor EGFR-TKI treatment are needed. Circulating DNA fragments carrying tumor specific sequence alterations [circulating cell-free tumor DNA (cftDNA)] are found in the cell-free fraction of blood, representing a variable and generally small fraction of the total circulating DNA. cftDNA has a high degree of specificity to detect EGFR gene mutations in NSCLC. Studies have shown the feasibility of using cftDNA to diagnosis of EGFR activating gene mutations and also to monitor tumor dynamics in NSCLC patients treated with EGFR-TKIs. These evidences suggested that non-invasive techniques based on blood samples had a great potential in EGFR mutated NSCLC patients. In this review, we summarized these non-invasive approaches and relative scientific data now available, considering their possible applications in clinical practice of NSCLC treatment.

Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma

PURPOSE

Genetic intratumoral heterogeneity has a profound influence on the selection of clinical treatment strategies and on addressing resistance to targeted therapy. The purpose of this study was to explore the potential effect of intratumoral heterogeneity on both genetic and pathologic characteristics of ALK-rearranged lung adenocarcinoma (LADC).

METHODS

We tested ALK fusions and EGFR mutations in 629 patients with LADC by using laser-capture microdissection to capture spatially separated tumor cell subpopulations in various adenocarcinoma subtypes and to test for ALK fusions and EGFR mutations in ALK-rearranged, EGFR-mutated, and ALK/EGFR coaltered LADCs to compare the oncogenic driver status between different tumor cell subpopulations in the same primary tumor.

RESULTS

Among the 629 patients, 30 (4.8%) had ALK fusions, 364 (57.9%) had EGFR mutations, and two had ALK fusions that coexisted with EGFR mutations. Intratumoral heterogeneity of ALK fusions were identified in nine patients by reverse-transcriptase polymerase chain reaction. In the two patients with an ALK/EGFR coaltered status, genetic intratumoral heterogeneity was observed both between different growth patterns and within the same growth pattern. The relative abundance of ALK and EGFR alterations was different in the same captured area. ALK fusions were positively associated with a micropapillary pattern (P = .002) and were negatively associated with a lepidic pattern (P = .008) in an expanded statistical analysis of 900 individual adenocarcinoma components, although they appeared to be more common in acinar-predominant LADCs in the analysis of 629 patients.

CONCLUSION

Intratumoral genetic heterogeneity was demonstrated to coexist with histologic heterogeneity in both single-driver and ALK/EGFR coaltered LADCs. Altered oncogenic drivers in spatially separated subclones of the same tumor may be different.

Role of circulating-tumor DNA analysis in non-small cell lung cancer

The discovery of actionable driver mutations such as epidermal growth factor receptor (EGFR) and microtubule-associated protein-like 4 anaplastic lymphoma kinase (EML4-ALK) and their highly responses to EGFR and ALK tyrosine kinase inhibitors (TKIs) in patients with advanced non-small-cell lung cancer (NSCLC) allowed precise medicine into reality. However, a substantial part of patients still have no sufficient tissue to perform genomic analysis. As a promising noninvasive biomarker and potential surrogate for the entire tumor genome, circulating tumor DNA (ctDNA) has been applied to the detection of driver gene mutations and epigenetic alteration and monitoring of tumor burden, acquired resistance, tumor heterogeneity and early diagnosis. Since precise therapy is a strategy that optimal therapy is decided based on simultaneous tumor genome information, ctDNA, as a liquid biopsy, may help to perform dynamic genetic surveillance. In this paper we will perspectively discuss the biology and identification of ctDNA in the blood of NSCLC patients and its clinical applications in patient management.

Rare discrepancies in a driver gene alteration within histologically heterogeneous primary lung cancers

OBJECTIVES

Most lung adenocarcinomas consist of mixtures of histological subtypes harboring different frequencies of driver gene mutations. However, little is known about intratumoral heterogeneity(ITH) within histologically heterogeneous primary lung cancers. Investigating key driver genes in respective morphological pattern is crucial to personalized treatment.

METHODS

Morphologically different areas within the same surgically resected adenocarcinomas were extracted from tissues to analyze gene status in each growth pattern. Driver genes, epidermal growth factor receptor (EGFR), KRAS and EML4-ALK, were assessed by assays with different sensitivities.

RESULTS

Seventy-nine consecutive eligible patients harboring a driver gene (EGFR=65; KRAS=10; EML4-ALK=4) were enrolled. For EGFR mutations, ITH occurred in 13.3% (8/60) by direct sequencing (DS) and 1.7% (1/60) by amplification refractory mutation system (ARMS) (P=0.016) among adenocarcinomas, but consistent within five adeno-squamous cell carcinomas by both methods. ITH among KRAS mutations were detected in 20% (2/10) by DS, whereas consistent (10/10) by high resolution melting. No discrepancies in EML4-ALK rearrangements existed according to fluorescence in situ hybridization.

CONCLUSION

Rare ITHs of EGFR/KRAS/EML4-ALK alterations within histologically heterogeneous primary lung adenocarcinomas existed by methods with higher sensitivity. Discrepancies might be due to abundance of mutant tumor cells and detection assays.

High-fidelity of non-small cell lung cancer xenograft models derived from bronchoscopy-guided biopsies

BACKGROUND

At present, there are two main types of lung cancer xenograft models: those derived from stable cell lines, and patient-derived xenograft models established by surgically resected tissues. However, these animal models may not reflect the biological and genetic characteristics of advanced non-small cell lung cancer (NSCLC). We utilized bronchoscopy-guided biopsy tissues of NSCLC patients to establish xenograft models and analyzed their histopathologic and genotypic fidelity with parental tumors.

METHODS

Tumor tissues of NSCLC patients taken via bronchoscope were subcutaneously implanted into mice with non-obese diabetic-severe combined immunodeficiency disease for model establishment and serial passage. The histopathology and genotype of the samples from bronchoscopy-guided biopsy-derived xenograft (BDX) models and their parental tumors were detected.

RESULTS

Thirty BDXs out of 114 NSCLC patients (26.32%) were successfully established. Smoking status significantly affected the success rate of NSCLC BDX establishment (P = 0.010). The BDX establishment success rate in squamous cell cancer was higher than in adenocarcinoma, with no significant difference (32.00% vs. 16.21%, P = 0.112). However, the growth rate of passage 1 BDX was slower than that of passages 2 and 3. Almost all NSCLC BDXs maintained similarity to their parental tumor tissues in regard to histologic characteristics, pathological markers, and driver-gene mutations. Only one BDX model lost the epidermal growth factor receptor mutation contained in tumor parental tissue, as a result of heterogeneity.

CONCLUSIONS

NSCLC BDXs maintained high fidelity of histopathology and genotype with their original tumors. NSCLC BDXs that possess the actual status of advanced lung carcinoma should be used in preclinical research.

PIK3CA mutational status in circulating tumor cells can change during disease recurrence or progression in patients with breast cancer

PURPOSE

Molecular characterization of circulating tumor cells (CTC) is crucial for the investigation of molecular-targeted therapies while PIK3CA somatic mutations play a crucial role in therapy response. We investigated the presence of PIK3CA mutations in CTC and whether this is associated with clinical outcome.

EXPERIMENTAL DESIGN

We developed and validated an ultrasensitive methodology for the detection of PIK3CA mutations that is based on a combination of allele-specific, asymmetric rapid PCR and melting analysis. We analyzed PIK3CA hotspot mutations in: (i) a training group consisting of EpCAM-positive CTC fraction from 37 patients with clinically confirmed metastasis, and 26 healthy female volunteers and 15 primary breast tumor tissues and (ii) an independent group consisting of EpCAM-positive CTC fraction from 57 metastatic and 118 operable breast cancer patients and 76 corresponding primary tumors.

RESULTS

The assay could detect 0.05% of mutated dsDNA in the presence of 99.95% wtDNA for both exons (9 and 20) and was highly specific (0/26 healthy donors). PIK3CA mutations were identified in EpCAM-positive CTC in 20 of 57(35.1%) and in 23 of 118 (19.5%) patients with metastatic and operable breast cancer, and in 45 of 76(59.2%) corresponding FFPEs. Our data indicate that PIK3CA mutational status in CTCs can change during disease progression and is associated with worse survival (P = 0.047).

CONCLUSIONS

PIK3CA hotspot mutations are present at a relatively high frequency in CTCs and their presence is associated with worse survival in patients with breast cancer with metastasis. Evaluation of PIK3CA mutational status in CTCs is a strategy with potential clinical application.

Cytotoxic chemotherapy may overcome the development of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) therapy

OBJECTIVES

In the first-line treatment of non-small cell lung cancer (NSCLC) harboring EGFR mutations, epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) has been shown to yield a longer progression-free survival (PFS) rate than platinum-doublet chemotherapy; however, after the initial response, most patients develop resistance to the EGFR-TKIs. We hypothesized that the insertion of platinum-doublet chemotherapy after the initial response to EGFR-TKIs might prevent the emergence of acquired resistance to EGFR-TKIs and prolong survival.

METHODS

We carried out a phase II study of the following first-line treatment for patients with advanced NSCLC harboring EGFR mutations. Gefitinib (250 mg) was administered on days 1-56. Then, after a two-week drug-free period, three cycles of cisplatin (80 mg/m2) and docetaxel (60 mg/m2) were administered on days 71, 92, and 113. Thereafter, gefitinib was re-started on day 134 and continued until disease progression. The primary endpoint was the two-year PFS rate.

RESULTS

A total of 34 patients were enrolled. Of the 33 eligible patients and 12 achieved a two-year PFS. Thus, this therapeutic strategy met the criterion for usefulness. The 1-, 2-, 3-, and 5-year PFS rates were 67.0%, 40.2%, 36.9%, and 22.0%, respectively, and the median PFS was 19.5 months. The 1-, 2-, 3- and 5-year survival rates were 90.6%, 71.9%, 64.8%, and 36.5% respectively, and the median survival time was 48.0 months.

CONCLUSION

These results indicate that the insertion of platinum-doublet chemotherapy might prevent the development of acquired resistance to EGFR-TKIs in patients with advanced NSCLC harboring EGFR mutations.

Exon 19 deletion of epidermal growth factor receptor is associated with prolonged survival in brain metastases from non-small-cell lung cancer

Brain metastasis (BM) is a poor prognostic factor for non-small-cell lung cancer (NSCLC). Recent studies have shown that oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) were effective for BM from NSCLC with EGFR mutation. However, the relationship between EGFR mutations and prognosis of NSCLC BM patients remains to be determined. In this study, we investigated the impact of EGFR mutation status on the survival of BM patients from NSCLC. One hundred six patients with BM from NSCLC were retrospectively reviewed. Thirty-three subjects (24.3 %) were confirmed to have an exon 19 deletion, while another 33 had an exon 21 point mutation (L858R) (24.3 %). Log-rank test and Cox proportional hazards model were used to analyze the impact of variables on survival. The median survival of NSCLC with BM was 8 months. Log-rank test analysis showed that Eastern Cooperative Oncology Group Performance Status (ECOG-PS) at BM (p < 0.0001), control of primary tumor (p = 0.005), pathology (p = 0.01), EGFR mutations (p = 0.045), and 19 exon deletion (p = 0.007) were associated with a longer survival. In a Cox proportional hazards model, EGFR exon 19 deletion (p = 0.034), control of primary tumor (p = 0.024), and ECOG PS at BM (p = 0.006) were found to be independent prognostic factors. Moreover, there were prognostic differences between groups according to Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) classification system (p < 0.0001). Exon 19 deletion is an independent prognostic factor in BM from NSCLC. It should be integrated into the prognostic scoring classification system for NSCLC.

Clinical outcome of epidermal growth factor receptor-tyrosine kinase inhibitors therapy for patients with overlapping kirsten rat sarcoma 2 viral oncogene homolog and epidermal growth factor receptor gene mutations

Background

Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) is the second most common mutated gene following epidermal growth factor receptor (EGFR) mutation in Chinese lung adenocarcinoma (LADC) patients. Investigating the clinical characteristics and outcomes of patients with co‐existing KRAS and EGFR mutations can provide significant information for suitable therapies.

Methods

We retrospectively investigated 2106 LADC patients who had undergone EGFR and KRAS mutation tests at the Peking University Cancer Hospital. Only advanced LADC patients who carried KRAS and/or EGFR mutations, received EGFR‐tyrosine kinase inhibitors (TKIs) and/or chemotherapy, and had completed follow‐up analysis were analyzed further. KRAS and EGFR mutations were tested by denaturing high‐performance liquid chromatography.

Results

A KRAS mutation was detected in 123 out of 2106 LADC patients (5.8%) and 38 (1.8%) had a concurrent EGFR mutation. Seventy‐two of 123 patients were advanced cases, which were divided into two sub‐groups according to EGFR mutation status: overlapping KRAS and EGFR mutations (n = 24) and KRAS mutation alone (n = 48). Clinical characteristics of the two subgroups were similar. A greater ratio of patients with double mutations received EGFR‐TKIs compared to KRAS mutation alone (75% vs. 43.8%, P = 0.012), and obtained a better objective response rate (38.9% vs. 9.5%, P = 0.027) and longer progression‐free survival (8.0 vs. 1.5 months, P = 0.028) following EGFR‐TKIs therapy. However, these differences were not observed in patients treated with platinum‐based chemotherapy.

Conclusions

Overlapping KRAS and EGFR mutations occurred in 1.8% of Chinese LADC patients studied. The co‐presence of EGFR mutations could predict a clinical benefit from EGFR‐TKIs treatment for patients with KRAS mutations.

Etoposide-cisplatin alternating with vinorelbine-cisplatin versus etoposide-cisplatin alone in patients with extensive disease combined with small cell lung cancer

BACKGROUND

The aim of this study was to evaluate the efficacy of alternating etoposide-cisplatin and vinorelbine-cisplatin (EP-NP) compared with an etoposide-cisplatin (EP) regimen for advanced combined small cell carcinomas.

MATERIALS AND METHODS

Histologically confirmed combined small cell carcinoma patients who met the inclusion criteria were randomly assigned (1:1) into either the EP-NP setting (group A) or the EP setting (group B). The primary endpoint was progression-free survival in patients who received at least one dose of treatment.

RESULTS

Eighty-two patients entered into this trial, 42 in group A and 40 in group B. The objective response rates in group A and group B were 42.9% and 32.5%, respectively (p=0.334). Survival analysis showed that median progression-free survival was 6.1 months in group A, which was significantly longer than the 4.1 months in group B (p=0.041). However, as to overall survival, no significant difference was found between the two groups (11.0 vs 10.1 months in groups A and B, respectively, p=0.545). No unexpected side effects were observed in either group.

CONCLUSIONS

The EP-NP regimen for combined small cell carcinomas prolonged progression- free survival compared with the EP regimen. Further clinical investigations are warranted.