The correlation between EGFR mutation status and the risk of brain metastasis in patients with lung adenocarcinoma

Treatment of brain metastases from non-small cell lung cancer: preclinical, clinical, and translational research

Lung cancer is the second most common type of cancer and is the leading cause of cancer-related deaths in the United States. Approximately 10-40% of patients with solid tumors develop brain metastases, with non-small cell lung cancer accounting for approximately 50% of all cases of patients with brain metastases. Many management options are available which can include surgery, radiation, and systemic therapy. A variety of factors go into the selection of management of brain metastases. In this review, we will focus on the treatment strategies and optimizing the management of brain metastases in patients with non-small cell lung cancer.

A Review of Recent Advances in the Molecular Mechanisms Underlying Brain Metastasis in Lung Cancer

Brain metastasis from lung cancer is a prevalent mode of treatment failure associated with a poor prognosis. The incidence of brain metastasis has recently shown a dramatic increase. The early detection and risk stratification of lung cancer-related brain metastasis would be highly advantageous for patients. However, our current knowledge and comprehension of the underlying mechanisms driving brain metastasis in lung cancer pose significant challenges. This review summarizes the mechanisms underlying brain metastasis, focusing on the intricate interplay between lung cancer-derived tumor cells and the unique characteristics of the brain, recent advancements in the identification of driver genes, concomitant genes, epigenetic features, including miRNAs and long noncoding RNAs, as well as the molecular characterization of brain metastasis originating from other organs, which may further enhance risk stratification and facilitate precise treatment strategies.

An association of epidermal growth factor receptor mutation subtypes with prognostic prediction and site-specific recurrence in advanced stage lung cancer patients

BACKGROUND

Concerning the different clinical behavior of epidermal growth factor receptor (EGFR) subtypes in advanced-stage lung cancer patients, the current study aimed to evaluate the clinical, pathological, and prognostic significance of EGFR mutation subtypes, and treatment response in patients with advanced-stage lung cancer.

METHODS AND RESULTS

A retrospective study enrolled a total of 346 patients with advanced-stage lung cancer tested for EGFR mutation. EGFR mutation was analyzed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Statistical analysis was performed using SPSS version 20.0. EGFR mutation was evident in 38% of patients with the highest prevalence of exon 19 deletions. A higher incidence of 19-deletions and 20-insertions were observed in young patients, while a higher incidence of L858R was noted in old age patients. Patients with de-novo T790M failed to improve their OS by any of the treatment modalities. Patients with de-novo T790M mutation have a higher risk of developing lung, liver, and multiple site metastases while patients with L858R mutation have a higher risk of developing brain metastasis. Additionally, patients with 19 deletion mutation did not improve their OS after receiving conventional chemotherapy hence, they demonstrate better survival only after EGFR-TKIs. Multivariate survival analysis predicted chemotherapy as an independent predictor of OS.

CONCLUSION

Besides clinicopathological and prognostic consequences of EGFR mutation and mutation subtypes, patients harboring TKI sensitive, or insensitive mutations reveal different secondary disease development and hence should be treated accordingly for better survival. Current findings may provide the basis for a better treatment strategy.

Worldwide Prevalence of Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer: A Meta-Analysis

Background

Identification of variable epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC) is important for the selection of appropriate targeted therapies. This meta-analysis was conducted to provide a worldwide overview of EGFR mutation and submutation (specifically exon 19 deletions, exon 21 L858R substitutions, and others) prevalence, and identify important covariates that influence EGFR mutation status in patients with advanced NSCLC to address this clinical data gap.

Methods

Embase^® and MEDLINE^® in Ovid were searched for studies published between 2004 and 2019 with cohorts of ≥ 50 adults with EGFR mutations, focusing on stage III/IV NSCLC (≤ 20% of patients with stage I/II NSCLC). Linear mixed-effects models were fitted to EGFR mutation endpoints using logistic transformation (logit), assuming a binomial distribution. The model included terms for an intercept reflecting European studies and further additive terms for other continents. EGFR submutations examined were exon 19 deletions, exon 21 L858R substitutions, and others.

Results

Of 3969 abstracts screened, 57 studies were included in the overall EGFR mutation analysis and 74 were included in the submutation analysis relative to the overall EGFR mutation population (Europe, n = 12; Asia, n = 51; North America, n = 5; Central America, n = 1; South America, n = 1; Oceania, n = 1; Global, n = 3). The final overall EGFR mutations model estimated Asian and European prevalence of 49.1% and 12.8%, respectively, and included an additive covariate for the proportion of male patients in a study. There were no significant covariates in the submutation analyses. Most submutations were actionable: exon 19 deletions (49.2% [Asia]; 48.4% [Europe]); exon 21 L858R substitutions (41.1% [Asia]; 29.9% [Europe]).

Conclusions

Although EGFR mutation prevalence was higher in Asian than Western countries, data support worldwide testing for EGFR overall and submutations to inform appropriate targeted treatment decisions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40291-021-00563-1.

Vimentin expression status is a potential biomarker for brain metastasis development in EGFR-mutant NSCLC patients

Background

Despite advances in systemic therapy and improvements in survival for advanced epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC), brain metastasis (BM) remains a poor outcome. Previous studies on risk factors for BM occurrence included unselected patients and biomarker prediction of BM in these populations were not well studied. We aimed to identify the role of epithelial mesenchymal transition (EMT) marker and clinical factors predicting BM in

EGFR

mutant NSCLC patients.

Methods

Advanced EGFR-mutant NSCLC patients in the King Chulalongkorn Memorial Hospital from January 2013 to December 2017 were included. Vimentin expression was assessed by immunohistochemistry. The correlation between vimentin expression and factors associated with BM occurrence was analyzed by univariate and multivariate analyses.

Results

304 patients were enrolled. Of these, 149 patients (49%) developed BM. In multivariate analysis, the occurrence of BM was associated with age <60 years, metastatic disease at diagnosis, and 3 or more metastatic sites. Moreover, positive vimentin expression was also found more common in patients with BM than those without BM (52.4% vs. 27.6%, respectively) and predicted overall BM development in EGFR-mutant patients (OR 2.53, 95% CI, 1.11–5.77; P=0.027). Overall survival (OS) was shorter in vimentin^positive group than in vimentin^negative group. Median OS was 20.0 months (95% CI, 14.51–25.51) and 30.9 months (95% CI, 20.99–40.84), respectively (HR, 1.57; P=0.04).

Conclusions

Younger patients with EGFR-mutant NSCLC who had high disease burden were more likely to develop BM. Vimentin served as a biomarker for predicting BM and poor prognostic factor in EGFR-mutant patients. EMT pathway may be considered as a therapeutic target in these high-risk populations.

Clinical Impacts of EGFR Mutation Status: Analysis of 5780 Surgically Resected Lung Cancer Cases

BACKGROUND

To elucidate the clinical, pathologic, and prognostic impacts of epidermal growth factor receptor (EGFR) mutation and mutation subtypes in early-stage lung cancer, the study investigators conducted a retrospective analysis of the Japanese Joint Committee of Lung Cancer Registry database (a nationwide database for patients with surgically resected lung cancer; n = 18,973).

METHODS

Of 13,951 patients classified as having nonsquamous non-small cell lung cancer in the database, 5780 patients (41.0%) had been tested for an EGFR mutation and were included in this study.

RESULTS

An EGFR mutation was detected in 2410 patients (41.7%), and the presence of an EGFR mutation was significantly correlated with clinicopathologic factors such as the presence of ground-glass opacity (P < .001) and better prognosis. Analysis of initial recurrence sites identified significantly higher frequencies of brain and adrenal gland metastases in patients with and without an EGFR mutation, respectively. Of 2410 patients with EGFR mutations, 983 (40.8%) had an exon 19 deletion (Exon 19 Del), 1170 (48.5%) had an L858R mutation, and 257 (10.7%) had other EGFR mutations. A higher smoking rate was found in patients with other EGFR mutations (P = .02). In the comparison of Exon 19 Del and L858R, we found that Exon 19 Del correlated with younger age (P < .001), a higher rate of pure solid tumors (P < .001), advanced pathologic stage (trend P < .001), and poorer recurrence-free survival (P = .001).

CONCLUSIONS

In addition to the clinicopathologic and prognostic impacts of EGFR mutation status, tumors with Exon 19 Del have a more aggressive phenotype and patients have a poorer prognosis than with L858R in early-stage lung cancers.

The optional approach of oncogene-addicted non-small cell lung cancer with brain metastases in the new generation targeted therapies era

In recent years, the study of the molecular characteristics of non-small cell lung cancer (NSCLC) has highlighted a specific role of some genes that represent important therapeutic targets, including epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS-1) and v-Raf murine sarcoma viral oncogene homolog B1 (BRAF). Patients with oncogene-addicted cancer benefit more from therapy with tyrosine kinase inhibitors (TKIs) than from chemotherapy. The brain is a preferred site for tumor spread in these patients. In addition, given greater control of extracranial disease and prolonged survival, the brain is often the first site of progression. Therefore, there is great interest in therapeutic approaches that optimize the control of intracranial disease associated with systemic drugs that, by penetrating the blood-brain barrier (BBB), may improve local control. On the latter, radiotherapy provides excellent efficacy but following the results of clinical trials with new brain penetrant drugs, the question of how and especially when to perform brain radiotherapy in patients with oncogene-addicted NSCLC remains open. Prospective studies may indicate which patients are most likely to benefit from combined use or in what sequence they will undergo systemic and radiotherapy treatment. Due to the heterogeneity of patients and the introduction of new generation TKIs, a multidisciplinary assessment for the best management of therapies in NSCLC patients with molecular driver alterations and brain metastases (BM) is required.

Distribution Of Brain Metastasis From Lung Cancer

PURPOSE

The prognosis of lung cancer with brain metastasis is poor. The purpose of this study was to investigate the distribution of brain metastasis and explore its relationship with pathology and genetic mutations.

PATIENTS AND METHODS

Between June 2015 and July 2018, 335 patients from Shandong Provincial Hospital affiliated to Shandong University who had been firstly diagnosed with brain metastasis from lung cancer were retrospectively reviewed. All metastatic lesions were detected in the corresponding area using magnetic resonance imaging (MRI).

RESULTS

A total of 2046 metastatic lesions were found. Of the 335 patients, 21.2% (71/335) had a single brain metastasis and 78.8% (264/335) had multiple lesions. The cerebellum (56%; 189/335), right parietal lobe (54%; 182/335), right frontal lobe (47%; 157/335), and left frontal lobe (45%; 152/335) were the regions with the highest incidence of brain metastasis. The different pathological types of lung cancer showed different distribution of brain metastasis. In lung adenocarcinoma, the left frontal lobe (53%; 111/208), right frontal lobe (48%; 100/208) and cerebellum (56%; 116/208) exhibited higher brain metastases, while the cerebellum (61%; 45/74) and the right frontal lobe (46%; 34/74) had the highest incidence of brain metastasis from small-cell carcinoma. For lung squamous cell carcinoma, the cerebellum (70%; 14/20) was the most common site for metastasis. Adenocarcinoma was the most common pathological type in patients regardless of the number of lesions (ie, single or multiple brain metastases). Comparison of 37 cases with epidermal growth factor receptor (EGFR) gene mutation versus 26 cases without mutations showed that there was no correlation between the distribution of brain metastasis and gene mutation.

CONCLUSION

The different pathological types of lung cancer demonstrate different distribution of brain metastasis. These findings may have significant implications in the diagnosis and treatment of brain metastasis from lung cancer.

MicroRNA-330-3p promotes brain metastasis and epithelial-mesenchymal transition via GRIA3 in non-small cell lung cancer

Brain metastasis (BM) is associated with poor prognosis in patients with non-small cell lung cancer (NSCLC). We sought to identify microRNAs (miRNAs) that could serve as biomarkers to differentiate NSCLC patients with and without BM. Logistic regression was conducted with 122 NSCLC patients (60 without BM, 62 with BM) to assess the association between miRNAs and BM. We confirmed several risk factors for BM and revealed that serum miR-330-3p levels are higher in NSCLC patients with BM than that without BM. Overexpression of miR-330-3p promoted proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of NSCLC cells in vitro and NSCLC tumorigenesis in vivo. Knocking down miR-330-3p suppressed this metastatic phenotype. We identified putative miR-330-3p target genes by comparing mRNA microarray analysis data from A549 cells after miR-330-3p knockdown with candidate miR-330-3p target genes predicted by public bioinformatic tools and luciferase reporter assays. We found that GRIA3 is a target of miR-330-3p and that miR-330-3p stimulates EMT progress by mediating GRIA3-TGF-β1 interaction. Our results provide novel insight into the role of miR-330-3p in NSCLC metastasis, and suggest miR-330-3p may be a useful biomarker for identifying NSCLC with metastatic potential.

EGFR-TKI plus brain radiotherapy versus EGFR-TKI alone in the management of EGFR-mutated NSCLC patients with brain metastases

Background

It has been confirmed that epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) presented better efficacy than brain radiotherapy (brain RT) in the treatment of brain metastasis (BM) in EGFR mutated NSCLC patients. However, whether the combination of EGFR-TKIs and brain RT is better than EGFR-TKIs alone remains unclear. We aim to compare the outcomes of adding brain RT to EGFR-TKIs and to screen for the beneficial population by a meta-analysis of currently available data.

Methods

A systematic search for relevant articles was conducted in six databases. The outcomes were overall survival (OS) and intracranial progression-free survival (iPFS) between groups, both were measured as hazard ratios (HRs). Meta-regression and dominant subgroup analysis were used to explore advantageous subgroups.

Results

A total of 12 retrospective studies involving 1,553 EGFR mutated patients with BM at the first diagnosis were included. EGFR-TKIs plus brain RT showed a significant prolonged OS (HR =0.64, 95% CI: 0.52-0.78; P<0.001) and iPFS (HR =0.62, 95% CI: 0.50-0.78; P<0.001) compared to EGFR-TKIs alone. Meta-regression analyses showed that potential factors contributed to the heterogeneity were the proportion of ECOG performance score (2+ vs. 0-1, P=0.070) and brain symptomatic patients (no vs. yes, P=0.077) regarding iPFS and was age (younger vs. older, P=0.075) for OS. Dominant subgroup analyses suggested that symptomatic patients (HR 0.46 vs. 0.74, interaction P=0.01) for iPFS, and older patients (HR 0.55 vs. 0.75, interaction P=0.03) and 19Del mutation (HR 0.55 vs. 0.74, interaction P=0.04) for OS, seemed to benefit more from the combination therapy than their counterparts. However, direct subgroup results based on only two studies did not show significant difference in iPFS benefit between age, mutation type and sex subgroup.

Conclusions

EGFR-TKIs plus brain RT is superior to EGFR-TKIs alone in the management of EGFR-mutated NSCLC patients with BM, of which the benefits might be influenced by age, BM-related symptoms and mutation type.

Brain metastases in resected non-small cell lung cancer: The impact of different tyrosine kinase inhibitors

Objectives

The purpose of this study was to examine the impact of epidermal growth factor receptor (EGFR) mutation status and tyrosine kinase inhibitors (TKIs) on the survival of brain metastases (BM) in patients with surgically resected non-small cell lung cancer (NSCLC).

Methods

We selected the patients who had developed metastatic NSCLC; analyzed the differences between brain metastases and other sites of metastases, including patient characteristics, EGFR status, and survival; and selected the patients who had BM for further investigation. We also compared the treatment effects of first-generation TKIs with those of second-/third-generation TKIs.

Results

A total of 785 cases of stage I-IIIa NSCLC were reviewed. Thirty-six (4.6%) patients were identified as having BM. Among them, 14 patients had a mutated EGFR status. No association between EGFR mutation and the incidence of BM was observed (p = 0.199). Patients with mutated EGFRs had significantly longer overall survival and post-recurrence survival than patients with wild-type EGFR mutation (p = 0.001 for both). However, there was no survival difference between patients with exon 19 and exon 21 mutations (p = 0.426). Furthermore, patients who received the second- and/or third-generation EGFR-TKIs had better survival than patients who only received first-generation EGFR-TKIs (p = 0.031). A multivariate analysis indicated that the next-generation TKIs (HR, 0.007; 95% CI, 0.000 to 0.556; p = 0.026) and a longer interval before BM development (HR, 0.848; 95% CI, 0.733 to 0.980; p = 0.025) were significant factors in longer survival.

Conclusions

EGFR-TKIs were effective in treating NSCLC patients with BM after curative pulmonary surgery, especially in those patients harboring EGFR mutations. Furthermore, the second-/third-generation EGFR-TKIs showed more promising results than the first-generation EGFR-TKIs in treating those particular patients, though larger studies needed to further prove the results.

A Comprehensive Meta-Analysis of Association between EGFR Mutation Status and Brain Metastases in NSCLC

Non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation have different clinicopathological characteristics compared with EGFR wild type NSCLC. A growing number of studies focused on the relevance between EGFR mutation status and brain metastases (BM) in NSCLC, but it remains controversial. Therefore, this study performed a comprehensive meta-analysis to untangle this issue. Several electronic databases including Pubmed, Embase, Web of science and Cochrane database were thoroughly searched. The odds ratio (OR) with 95% confidence interval (95%CI) was pooled to evaluate the relevance. Meta-regression analysis and subgroup analysis were conducted according to the heterogeneity. A total of 26 studies were identified finally in this meta-analysis. The overall OR was 1.58 (95%CI: 1.36-1.84), which indicated that EGFR mutation had a positive association with BM of NSCLC. The subgroup analysis resulted from eleven studies with lung adenocarcinoma revealed a higher possibility of BM in NSCLC with EGFR mutation compared with EGFR wild (p < 0.05). There was no significant difference in the risk of BM between NSCLC EGFR exon 19 mutation and exon 21 point mutation (p = 0.23). This meta-analysis suggests that EGFR mutation can be a risk factor for BM in NSCLC.

[Mechanism of EGFR Over-expression and Mutations Leading to Biological Characteristics Changes of Human Lung Adenocarcinoma Cells through CXCR4/CXCL12 Signaling Pathway]

BACKGROUND

The epidermal growth factor receptor (EFGR) mutation was closely related to the invasion and metastasis of lung adenocarcinoma and the biological axis of CXCR4/CXCL12 (chemokine receptor 4/chemokine ligand 12) played an important role in the organ-specific metastasis of the tumor. It was a question surrounding whether there is interaction between them in the process of lung adenocarcinoma metastasis. To investigate the potential molecular mechanisms of EGFR over-expression and EFGR-mutations effects on cell proliferation, migration and invasion, we constructed EGFR over-expression and three EFGR-mutant human lung adenocarcinoma H1299 cell sublines.

METHODS

EGFR over-expression and three EFGR-mutant (EGFR-E746-A750del, EGFR-T790M and EGFR-L858R) plasmid were designed and transfected H1299 cells with Lipofectamine 2000. H1299 cells transfected with empty vector were negative control (NC), and H1299 cells without transfection were set as blank control (BC). The effects of EGFR over-expression and mutations on the proliferation, migration and invasion of H1299 cells were detected by cell cloning assay, wound healing assay and Transwell assay. The mRNA and protein expression levels of MMP-2, MMP-9, CXCR4 and CXCL12 were detected by RT-PCR and Western blot.

RESULTS

Compared with negative control group and blank control group, EGFR over-expression and EGFR-E746-A750 deletion have significantly higher colony formation (28±2, 28.33±4.16; respectively) (P<0.05) and the cell migration and invasion ability were significantly increased (P<0.05). RT-PCR and Western blot assay showed that the mRNA and protein expression of MMP-2, MMP-9, CXCR4 and CXCL12 in EGFR over-expression and EGFR-E746-A750 deletion group were remarkably higher than that in negative control and blank control group (P<0.05).

CONCLUSIONS

EGFR over-expression and 19 exon deletion can promote the expression of MMP-2 and MMP-9 by up-regulating CXCR4/CXCL12 signaling pathway, leading to the change of tumor biological characteristics such as higher proliferation, migration and invasion ability.

Treating EGFR-Mutated Oncogene-Addicted Advanced Non-Small-Cell Lung Cancer in the Era of Economic Crisis in Greece: Challenges and Opportunities

PURPOSE

Because of the profound financial crisis that commenced in Greece in 2010, severe cuts in health care spending and other restriction measures led to significant delays in the reimbursement of novel antineoplastic agents. In 2011, the Hellenic Society of Medical Oncology initiated a program of early access to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors for the treatment of patients with advanced, EGFR-mutant non-small-cell lung cancer (NSCLC). We evaluated treatment patterns and clinical outcomes in patients with EGFR-mutant or wild-type disease treated at a large center in Greece throughout the period of financial crisis.

PATIENTS AND METHODS

From 2011 through 2015, 252 patients with newly diagnosed advanced NSCLC were treated at the Department of Medical Oncology of the Papageorgiou Hospital, a tertiary cancer center in northern Greece. We retrospectively reviewed patient medical records to obtain clinicopathologic characteristics, EGFR mutation status, and follow-up data. The primary end point was time to treatment failure.

RESULTS

Of the 198 evaluable patients, 25 (12%) had EGFR mutations. All patients with EGFR mutations except one received treatment with an EGFR tyrosine kinase inhibitor. Median times to treatment failure for patients with EGFR-mutant and wild-type disease were 15.8 and 7.1 months, respectively (hazard ratio, 0.58; 95% CI, 0.35 to 0.95; P = .031). There was no difference in overall survival between the two groups ( P = .293). No deviation from treatment guidelines or discontinuation of treatment regimens occurred because of logistic reasons or drug shortages.

CONCLUSION

Despite restrictions in the reimbursement policy and accompanying controls in the use of high-cost medicines, the national program enabled treatment of patients with EGFR-mutant NSCLC according to established guidelines. Therefore, the clinical outcomes of such patients treated in Greece during the economic crisis were in accordance with international standards.

Role of Recursive Partitioning Analysis and Graded Prognostic Assessment on Identifying Non-Small Cell Lung Cancer Patients with Brain Metastases Who May Benefit from Postradiation Systemic Therapy

Background

The role of postradiation systemic therapy in non-small cell lung cancer (NSCLC) patients with brain metastasis (BM) was controversial. Thus, we explored the role of Radiation Therapy Oncology Group recursive partitioning analysis (RTOG-RPA) and graded prognostic assessment (GPA) in identifying population who may benefit from postradiation systemic therapy.

Methods

The clinical data of NSCLC patients with documented BM from August 2007 to April 2015 of two hospitals were studied retrospectively. Cox regression was used for multivariate analysis. Survival of patients with or without postradiation systemic therapy was compared in subgroups stratified according to RTOG-RPA or GPA.

Results

Of 216 included patients, 67.1% received stereotactic radiosurgery (SRS), 24.1% received whole-brain radiation therapy (WBRT), and 8.8% received both. After radiotherapy, systemic therapy was administered in 58.3% of patients. Multivariate analysis found that postradiation systemic therapy (yes vs. no) (hazard ratio [HR] = 0.361, 95% confidence interval [CI] = 0.202-0.648, P = 0.001), radiation technique (SRS vs. WBRT) (HR = 0.462, 95% CI = 0.238-0.849, P = 0.022), extracranial metastasis (yes vs. no) (HR = 3.970, 95% CI = 1.757-8.970, P = 0.001), and Karnofsky performance status (<70 vs. ≥70) (HR = 5.338, 95% CI = 2.829-10.072, P < 0.001) were independent factors for survival. Further analysis found that subsequent tyrosine kinase inhibitor (TKI) therapy could significantly reduce the risk of mortality of patients in RTOG-RPA Class II (HR = 0.411, 95% CI = 0.183-0.923, P = 0.031) or with a GPA score of 1.5-2.5 (HR = 0.420, 95% CI = 0.182-0.968, P = 0.042). However, none of the subgroups stratified according to RTOG-RPA or GPA benefited from the additional conventional chemotherapy.

Conclusion

RTOG-RPA and GPA may be useful to identify beneficial populations in NSCLC patients with BM if TKIs were chosen as postradiation systemic therapy.

Risk factors and treatments for brain metastasis in patients with adenocarcinoma of the lung: a retrospective analysis of 373 patients

Background

Risk factors and treatments for brain metastasis (BM) in patients with adenocarcinoma have not been fully profiled in previous studies because of the enrolment of patients with tumours of mixed histology. Thus, we specifically addressed the issue in patients with adenocarcinoma.

Methods

Clinical data for 373 patients with pathologically confirmed adenocarcinoma were studied retrospectively. Factors including age (≤60 vs. > 60), gender (male vs. female), stage at diagnosis, T status (T1–2 vs. T3–4), N status (N0–1 vs. N2–3), epidermal growth factor receptor (EGFR) mutation status (wild-type vs. mutant) and smoking status (never vs. current) were analyzed.

Results

In multivariate analysis, age (P = 0.006) and N status (P = 0.041) were independent risk factors for BM. In patients with BM, adding systemic therapy to local therapy improved median post-brain-metastasis survival (mPBMS) (P = 0.02). However, if stratification was conducted according to the recursive partitioning analysis (RPA) classification or graded prognostic assessment (GPA) scoring, only patients in RPA class II (P = 0.020) or with GPA score 1.5-2.5 (P = 0.032) could benefit from local plus systemic therapy. Those who received both pemetrexed and tyrosine kinase inhibitors (TKIs) as systemic therapies had a longer mPBMS than those who received TKIs alone, regardless of whether local therapy was applied. In patients with EGFR-sensitive mutations, TKIs therapy led to a longer mPBMS than conventional chemotherapy (P = 0.002).

Conclusions

Adenocarcinoma patients who were younger than 60 years of age and those with N2–3 disease have a significantly higher risk of BM. The addition of systemic therapy to local therapy can significantly prolong mPBMS, but the survival benefit confined in certain populations. Patients with opportunity to receive both pemetrexed and TKIs had the longest mPBMS.

COL5A1 may contribute the metastasis of lung adenocarcinoma

BACKGROUND

Lung cancer leads to the largest number of cancer-related deaths worldwide and is usually accompanied with metastasis which is the primary cause of those death and correlated with poor prognosis. However, the mechanism of lung cancer metastasis is still lack of definition.

METHODS

We compared the primary lung adenocarcinoma (AD) and its metastasis tissues induced by overexpression of Kras^G12D and inactivation of P53 in mouse lungs by analyzing GSE40222 about the differentially expressed genes (DEGs), pathways and hub genes. And human lung AD databases are used to verify the conversed changes of identified key gene and then followed functional studies are performed to explore the functions of key gene.

RESULTS

We identified 165 genes differentially expressed in lung AD metastasis compared to primary AD. Pathway analysis identified 649 GO biological processes and 8 KEGG pathways, such as ECM-receptor interaction. Biological network interaction identified the hub genes during lung adenocarcinoma metastasis, such as the up-regulated COL5A1, a novel gene in AD metastasis. We found it's also increased in human AD and advanced stage. Knockdown of COL5A1 in human AD metastatic cells inhibited cell growth and invasion, and induced cell apoptosis. Notably, higher expression of COL5A1 was observed in the lung AD patients with recurrence and short survive.

CONCLUSION

By analyzing mouse lung AD and its metastases, we identified the potential key genes and pathways regulating lung AD metastasis, such as COL5A1. The following analysis of COL5A1 in human AD database and cells explores its functions, holding the implications of target therapy in AD metastasis and also providing more clues for future studies.

Clinical characteristics of T790M-positive lung adenocarcinoma after resistance to epidermal growth factor receptor-tyrosine kinase inhibitors with an emphasis on brain metastasis and survival

OBJECTIVES

We aimed to investigate the clinical characteristics of lung adenocarcinomas with acquired EGFR T790M mutation focusing on brain metastasis and survival.

MATERIALS AND METHODS

Our study included patients who had lung adenocarcinoma harboring EGFR mutation at 1st biopsy and then underwent 2nd biopsy after resistance to first- or second-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). Statistical analyses were performed to examine the associations between clinicopathologic features of lung adenocarcinoma and presence of acquired T790M mutation.

RESULTS

A total of 111 patients were identified. Of these, 58 patients (52.3%) had acquired T790M mutations. Osimertinib was used in 29 patients (26.1%) after resistance to first- or second-generation TKIs. The T790M mutation was more frequently found in patients with exon 19 deletion than in those with L858R mutations (p = .026) and in patients who had longer treatment duration with EGFR-TKI (p = .0398). Multivariate analysis revealed that exon 19 deletion (p = .003) were independently associated with T790M mutation. Patients with acquired T790M mutation showed a longer progression-free survival. In addition, patients who had T790M mutation or who received osimertinib treatment had a longer overall and post-progression survival than patients who did not. Brain metastasis-free survival was also longer in the T790M-positive group or osimertinib-treated group among patients who had no brain metastasis at the time of diagnosis. Osimertinib treatment was independently associated with longer overall, post-progression, and brain metastasis-free survival.

CONCLUSION

The status of acquired T790M mutation was correlated with exon 19 deletion and longer progression-free survival to first- or second-generation EGFR-TKIs. A third-generation EGFR-TKI, osimertinib, was strongly associated with brain metastasis-free survival as well as other survival indicators in patients with EGFR-mutant lung adenocarcinoma.

A retrospective analysis in patients with EGFR-mutant lung adenocarcinoma: is EGFR mutation associated with a higher incidence of brain metastasis?

Lung adenocarcinomas are more commonly associated with brain metastases (BM). Epidermal growth factor receptor (EGFR) mutations have been demonstrated to be both predictive and prognostic for patients with lung adenocarcinoma. We aimed to explore the potential association between EGFR mutation and the risk of BM in pulmonary adenocarcinoma patients. Data of 234 patients from 2007 to 2014 were retrospectively reviewed. A total of 108 patients had EGFR mutations in the entire cohort. Among them, 76 patients developed BM during their disease course. The incidence of BM was statistically higher in patients with EGFR mutations both at initial diagnosis (P=0.014) and at last follow-up (P<0.001). Multivariate logistic regression analysis revealed that EGFR mutation significantly increased the risk of BM at initial diagnosis (OR=2.515, P=0.022). In patients without BM at initial diagnosis, the accumulative rate of subsequent BM was significantly higher with EGFR mutations (P=0.001). Multivariate Cox regression analysis identified EGFR mutation as the only independent risk factor for subsequent BM (HR=3.036, P=0.001). Patients with EGFR mutations demonstrated longer overall survival (OS) after BM diagnosis than patients with wild-type EGFR (P=0.028). Our data suggest that EGFR mutation is an independent predictive and prognostic risk factor for BM and a positive predictive factor for OS in patients with BM.

The impact of EGFR mutations on the incidence and survival of stages I to III NSCLC patients with subsequent brain metastasis

Previous studies have demonstrated the association between EGFR mutations and distant metastasis. However, the association for subsequent brain metastasis (BM) in stages I-III non-small cell lung cancer (NSCLC) patients remains inconclusive. We conducted a retrospective analysis to clarify the impact of EGFR mutations on the incidence of BM and associated survival in patients with stage I-III NSCLC. A total of 491 patients screened for EGFR mutations were retrospectively enrolled. Brain MRI or CT was used to detect the BM. Cumulative incidence of subsequent BM and overall survival (OS) after diagnosis of BM were estimated by the Kaplan-Meier method and compared using log-rank test. We performed Cox proportional hazard regression for predictors of subsequent BM and determinants of OS after BM. The cumulative incidence of BM seemed higher in patients harboring EGFR mutations than those without EGFR mutations although it did not reach statistical significance (hazard ratio [HR] = 1.75, 95% confidence interval [CI] = 0.73~1.81). After adjusting possible confounders, including age, smoking, stage, and tumor size, EGFR mutation became one of the predictors for subsequent BM (HR = 1.89, 95% CI = 1.12~3.17, p = 0.017). Though there was no statistical difference in survival after BM between patients with EGFR mutations and wild-type EGFR (median survival: 17.8 vs. 12.2 months, HR = 0.79, 95% CI = 0.45–1.40), patients with EGFR 19 deletion (Del) tended to have a longer survival after BM than the non-EGFR 19 Del group (median survival: 29.4 vs. 14.3 months, HR 0.58, 95% CI = 0.32–1.09, p = 0.089). In conclusion, our data suggested EGFR mutation to be one of the predictors for subsequent BM in stage I-III patients. Given the small sample size, more studies are warranted to corroborate our results.

Commentary: Treatment Considerations for Patients With Epidermal Growth Factor Receptor-Mutated Non-Small Cell Lung Cancer Brain Metastases in the Era of Tyrosine Kinase Inhibitors

Brain metastasis is a serious complication of non-small cell lung cancer (NSCLC) affecting up to 40% of NSCLC patients. A subset of NSCLC tumors has mutations in the epidermal growth factor receptor (EGFR) gene, and determination of tumor EGFR mutation status is essential in guiding treatment decisions, as it directly affects the treatment approach. Patients with EGFR-mutated NSCLC have a higher cumulative incidence of brain metastases, and are especially sensitive to EGFR tyrosine kinase inhibitors (TKIs). Patients with newly diagnosed EGFR-mutated lung cancer presenting to a neurosurgeon with a new diagnosis of brain metastases now have a variety of treatment options available, including whole brain radiation therapy, stereotactic radiosurgery, surgical resection, chemotherapy, and targeted therapeutics such as the EGFR TKIs. In this review, we discuss the impact of EGFR mutation status on brain and leptomeningeal metastasis treatment considerations. Additionally, we present clinical cases of patients treated with EGFR TKIs alone and in combination with other therapies to highlight treatment alternatives.

Correlation between EGFR mutation status and the incidence of brain metastases in patients with non-small cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer-related death worldwide. Numerous studies have been performed to investigate the correlation between epidermal growth factor receptor (EGFR) mutation status and the incidence of brain metastases (BMs) in patients with non-small cell lung cancer (NSCLC), however, the outcomes were inconsistent. Thus, we performed this study to establish the role of EGFR mutation status in BMs.

METHODS

Electronic databases PubMed, Embase, Cochrane Library, CBM, WanFang, CNKI were searched to identify relevant trials. The primary endpoint was the incidence of BMs in EGFR mutations or wild type NSCLC and the secondary endpoint was overall survival calculated from the BMs emerging (BMOS).

RESULTS

Twenty-two studies incorporating 8,152 participants were eligible. EGFR mutations group possessed a significantly higher risk of BMs (OR =1.99; 95% CI, 1.59-2.48; P=0.000) than EGFR wild type group. In the stratified analysis, compared with EGFR wild type group, EGFR mutations group had a significant higher incidence (OR =2.01; 95% CI, 1.56-2.59; P=0.000) of subsequent BMs while only a trend of increasing the incidence of initial BMs (OR =1.38; 95% CI, 0.98-1.94; P=0.066). Moreover, exon 19 deletion had a trend of increasing the incidence of BMs than exon 21 mutation (OR =1.44; 95% CI, 0.77-2.68; P=0.252). Compared with EGFR wild type group, EGFR mutations group possessed a prolonged overall BMOS (HR =0.68; 95% CI, 0.47-0.98; P=0.038) and a longer BMOS in initial BMs (HR =0.50; 95% CI, 0.31-0.80; P=0.004) but no significant difference in NSCLC with subsequent BMs (HR =0.95; 95% CI, 0.42-2.15; P=0.901).

CONCLUSIONS

Patients with EGFR mutations were more susceptible to develop into BMs than those with EGFR wild type, especially during the course of disease.

Brain metastases in patients with non-small cell lung cancer: the role of mutated-EGFRs with an exon 19 deletion or L858R point mutation in cancer cell dissemination

Non-small cell lung cancer (NSCLC) patients tend to develop brain metastases (BM), but the link between BM occurrence and driver mutations in NSCLC is not very clear. We explored whether activating mutations of epidermal growth factor receptors (EGFRs) in exon 19 deletion or L858R predict BM in NSCLC. A retrospective multivariable logistic regression analysis of 384 patients demonstrated that the presence of mutated-EGFRs was associated with overall BM (OR=2.24, P=0.001) compared to that of wild-type EGFR (WT-EGFR). Moreover, the time-to-event analysis model considering death as a competing risk revealed that, irrespective of survival, mutated-EGFRs predicted subsequent BM (SBM) in stage IIIB-IV patients (37.1% vs. 10.6%, HR=2.98, P=0.002) after adjusting for age (HR=2.00, P=0.012), gender, histological subtype, and smoking history. Notably, the younger mutated-EGFR subgroup was at a higher risk for SBM compared to the older WT-EGFR one (58.1% vs.10.9%, HR=6.57, P<0.001). Additionally, EGFR exon 19 deletion, despite having a slightly longer overall survival (20.6 vs. 14.2 months, P=0.368), was comparable to L858R mutation in predicting SBM (39.5% vs. 34.5%, HR=0.91, P=0.770). In vitro, the overexpression of mutated-EGFRs induced morphological changes towards a mesenchymal-like phenotype and promoted mobility in lung cancer cells. Clinically, mutated-EGFR NSCLC displayed a higher proportion of vimentin-positive expression (75.3% vs. 51.2%; P=0.007) and a shorter median time to SBM (23.5 months vs. not reached, P=0.017) than WT-EGFR NSCLC. These results suggest that NSCLC patients carrying mutated-EGFRs may require a higher frequency of brain imaging assessments than those with WT-EGFR to facilitate earlier SBM detection during follow-up.

Brain metastasis in non-small cell lung cancer (NSCLC) patients with uncommon EGFR mutations: a report of seven cases and literature review

Brain metastasis (BM) arising from non-small cell lung cancer (NSCLC) with rare epidermal growth factor receptor (EGFR) mutations is quite rare. The prognosis and therapeutic effects of BM remain enigmatic. To the best of our knowledge, this is the first report to make a separate analysis of BM from NSCLC patients with original uncommon EGFR mutations. We retrospectively reviewed 7 cases of BM arising from 42 cases of uncommon EGFR mutated lung cancer in Tianjin Medical University Cancer Institute and Hospital. We also performed a literature review to assess therapeutic features and outcomes.

EGFR and KRAS Mutations Predict the Incidence and Outcome of Brain Metastases in Non-Small Cell Lung Cancer

Background: Lung cancer is the leading cause of brain metastases (BM). The identification of driver oncogenes and matched targeted therapies has improved outcome in non-small cell lung cancer (NSCLC) patients; however, a better understanding of BM molecular biology is needed to further drive the process in this field. Methods: In this observational study, stage IV NSCLC patients tested for EGFR and KRAS mutations were selected, and BM incidence, recurrence and patients’ outcome were assessed. Results: A total of 144 patients (142 Caucasian and two Asian) were selected, including 11.27% with EGFR-mutant and 33.10% with KRAS-mutant tumors, and 57.04% patients had developed BM. BM incidence was more frequent in patients with EGFR mutation according to multivariate analyses (MVA) (Odds ratio OR = 8.745 [1.743–43.881], p = 0.008). Among patients with treated BM, recurrence after local treatment was less frequent in patients with KRAS mutation (OR = 0.234 [0.078–0.699], p = 0.009). Among patients with untreated BM, overall survival (OS) was shorter for patients with KRAS mutation according to univariate analysis (OR = 7.130 [1.240–41.012], p = 0.028), but not MVA. Conclusions: EGFR and KRAS mutations have a predictive role on BM incidence, recurrence and outcome in Caucasian NSCLC patients. These results may impact the routine management of disease in these patients. Further studies are required to assess the influence of other biomarkers on NSCLC BM.

Epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of central nervous system metastases from non-small cell lung cancer: the present and the future

Lung cancer is one of the major causes of cancer related mortality worldwide. Brain metastases (BM) complicate clinical evolution of non-small cell lung cancer (NSCLC) in approximately 25-40% of cases, adversely influencing quality of life (QoL) and overall survival (OS). Systemic therapy remains the standard strategy for metastatic disease. Nevertheless, the blood-brain barrier (BBB) makes central nervous system (CNS) a sanctuary site. To date, the combination of chemotherapy with whole brain radiation therapy (WBRT), surgery and/or stereotactic radiosurgery (SRS) represents the most used treatment for patients (pts) with intracranial involvement. However, due to their clinical conditions, many pts are not able to undergo local treatments. Targeted therapies directed against epidermal growth factor receptor (EGFR), such as gefitinib, erlotinib and afatinib, achieved important improvements in EGFR mutated NSCLC with favorable toxicity profile. Although their role is not well defined, the reported objective response rate (ORR) and the good tolerance make EGFR-tyrosine kinase inhibitors (TKIs) an interesting valid alternative for NSCLC pts with BM, especially for those harboring EGFR mutations. Furthermore, new-generation TKIs, such as osimertinib and rociletinib, have already shown important activity on intracranial disease and several trials are still ongoing to evaluate their efficacy. In this review we want to highlight literature data about the use and the effectiveness of EGFR-TKIs in pts with BM from NSCLC.

Epidermal Growth Factor Receptor Mutation Enhances Expression of Cadherin-5 in Lung Cancer Cells

Epidermal growth factor receptor (EGFR) activation has been shown to play a critical role in tumor angiogenesis. In this study, we investigate the correlation between EGFR mutations and cadherin-5 (CDH5), which is an angiogenic factor, in lung cancer cells. Increased expression CDH5 is observed in lung cancer cells with EGFR mutations. Stable lung cancer cell lines expressing mutant (exon 19 deletion E746-A750, and exon 21 missense mutation L858R) and wild type EGFR genes are established. A significantly higher expression of CDH5 is observed in exon 19 deletion stable lung cancer cells and mouse xenografts. Further studies show that expression of CDH5 is decreased after the inhibition of EGFR and downstream Akt pathways in lung cancer cells with EGFR mutation. In addition, mutant EGFR genes potentiates angiogenesis in lung cancer cells, which is inhibited by CDH5 siRNA, and potentiates migration and invasion in lung cancer cells. Our study shows that mutant EGFR genes are associated with overexpression of CDH5 through increased phosphorylation of EGFR and downstream Akt pathways. Our result may provide an insight into the association of mutant EGFR and CDH5 expression in lung cancer and aid further development of target therapy for NSCLC in the future.