Epidermal Growth Factor Receptor Gene in Primary Tumor and Metastatic Sites from Non-small Cell Lung Cancer

Predicting the T790M mutation in non-small cell lung cancer (NSCLC) using brain metastasis MR radiomics: a study with an imbalanced dataset

BACKGROUND

Early detection of T790M mutation in exon 20 of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) patients with brain metastasis is crucial for optimizing treatment strategies. In this study, we developed radiomics models to distinguish NSCLC patients with T790M-positive mutations from those with T790M-negative mutations using multisequence MR images of brain metastasis despite an imbalanced dataset. Various resampling techniques and classifiers were employed to identify the most effective strategy.

METHODS

Radiomic analyses were conducted on a dataset comprising 125 patients, consisting of 18 with EGFR T790M-positive mutations and 107 with T790M-negative mutations. Seventeen first- and second-order statistical features were selected from CET1WI, T2WI, T2FLAIR, and DWI images. Four classifiers (logistic regression, support vector machine, random forest [RF], and extreme gradient boosting [XGBoost]) were evaluated under 13 different resampling conditions.

RESULTS

The area under the curve (AUC) value achieved was 0.89, using the SVM-SMOTE oversampling method in combination with the XGBoost classifier. This performance was measured against the AUC reported in the literature, serving as an upper-bound reference. Additionally, comparable results were observed with other oversampling methods paired with RF or XGBoost classifiers.

CONCLUSIONS

Our study demonstrates that, even when dealing with an imbalanced EGFR T790M dataset, reasonable predictive outcomes can be achieved by employing an appropriate combination of resampling techniques and classifiers. This approach has significant potential for enhancing T790M mutation detection in NSCLC patients with brain metastasis.

[Brain metastases]

Cerebral metastases in patients with metastatic lung cancer are found in more than 30% of patients at baseline and manifest themselves in two out of three patients during disease evolution. For a long time, the cerebral manifestation of the disease was classified as prognostically unfavorable and hence such patients were regularly excluded from therapy studies. In the context of targeted molecular therapy strategies and established immuno-oncological systemic therapies, the blood-brain barrier no longer represents an insurmountable barrier. However, the treatment of brain metastases requires decision making in a multidisciplinary team within dedicated lung cancer and/or oncology centers. The differentiated treatment decision is based on the number, size and location of the brain metastases, neurology and general condition, comorbidities, potential life expectancy and the patient's wishes, but also tumor biology including molecular targets, extra-cranial tumor burden and availability of a CNS-effective therapy. Systemic therapies as well as neurosurgical and radiotherapeutic concepts are now often combined for optimized and prognosis-improving therapeutic strategies.

Machine-Learning-Aided Prediction of Brain Metastases Development in Non-Small-Cell Lung Cancers

PURPOSE

Non-small-cell lung cancer (NSCLC) shows a high incidence of brain metastases (BM). Early detection is crucial to improve clinical prospects. We trained and validated classifier models to identify patients with a high risk of developing BM, as they could potentially benefit from surveillance brain MRI.

METHODS

Consecutive patients with an initial diagnosis of NSCLC from January 2011 to April 2019 and an in-house chest-CT scan (staging) were retrospectively recruited at a German lung cancer center. Brain imaging was performed at initial diagnosis and in case of neurological symptoms (follow-up). Subjects lost to follow-up or still alive without BM at the data cut-off point (12/2020) were excluded. Covariates included clinical and/or 3D-radiomics-features of the primary tumor from staging chest-CT. Four machine learning models for prediction (80/20 training) were compared. Gini Importance and SHAP were used as measures of importance; sensitivity, specificity, area under the precision-recall curve, and Matthew's Correlation Coefficient as evaluation metrics.

RESULTS

Three hundred and ninety-five patients compromised the clinical cohort. Predictive models based on clinical features offered the best performance (tuned to maximize recall: sensitivity∼70%, specificity∼60%). Radiomics features failed to provide sufficient information, likely due to the heterogeneity of imaging data. Adenocarcinoma histology, lymph node invasion, and histological tumor grade were positively correlated with the prediction of BM, age, and squamous cell carcinoma histology were negatively correlated. A subgroup discovery analysis identified 2 candidate patient subpopulations appearing to present a higher risk of BM (female patients + adenocarcinoma histology, adenocarcinoma patients + no other distant metastases).

CONCLUSION

Analysis of the importance of input features suggests that the models are learning the relevant relationships between clinical features/development of BM. A higher number of samples is to be prioritized to improve performance. Employed prospectively at initial diagnosis, such models can help select high-risk subgroups for surveillance brain MRI.

Heterogeneity and Clinical Effect of Epidermal Growth Factor Receptor in Primary Lung and Brain Metastases of Nonsmall Cell Lung Cancer

INTRODUCTION

This study aimed to analyze the heterogeneity in epidermal growth factor receptor (EGFR) gene mutation and its impact on clinical outcomes in primary tumor and corresponding brain metastasis (BM) in nonsmall cell lung cancer (NSCLC).

MATERIALS AND METHODS

Primary pulmonary tumors and paired BMs of 27 NSCLC patients were surgically removed. All brain lesions were histologically confirmed as metastatic NSCLC. EGFR gene mutation status was detected by using amplification refraction mutation system. McNemar test was performed to compare EGFR mutation status between lung primary tumors and metastatic brain tumors and Kappa test was performed to quantify the agreement between the two.

RESULTS

Of the 27 patients, nine cases were found to have EGFR mutations in BMs and 10 had a positive EGFR mutation status in primary lung tumor tissue. The rate of consistency of the matched tumor was 24/27 (88.9%). Among the three cases presenting EGFR mutational heterogeneity, two patients harbored an EGFR mutation in the primary tumor but not in the BMs; meanwhile, the last patient demonstrated the opposite pattern. Compared to patients with consistent EGFR mutations, patients with inconsistent mutations showed better outcomes. Further analysis revealed that the two patients whose EGFR mutant-type primary tumor progressed to wild-type cerebral metastatic tumor had longer overall survival than the patient whose EGFR wild-type primary tumor progressed to mutant-type brain metastatic tumor.

CONCLUSIONS

Heterogeneity of EGFR mutation status was observed between primary NSCLC and paired BM. Patients possessing a wild-type EGFR mutation in BM might have better outcomes, especially those with transition from mutant to wild-type.

Radiomic Signatures for Predicting EGFR Mutation Status in Lung Cancer Brain Metastases

Background

Lung cancer is the most common primary tumor metastasizing to the brain. A significant proportion of lung cancer patients show epidermal growth factor receptor (EGFR) mutation status discordance between the primary cancer and the corresponding brain metastases, which can affect prognosis and therapeutic decision-making. However, it is not always feasible to obtain brain metastases samples. The aim of this study was to establish a radiomic model to predict the EGFR mutation status of lung cancer brain metastases.

Methods

Data from 162 patients with resected brain metastases originating from lung cancer (70 with mutant EGFR, 92 with wild-type EGFR) were retrospectively analyzed. Radiomic features were extracted using preoperative brain magnetic resonance (MR) images (contrast-enhanced T1-weighted imaging, T1CE; T2-weighted imaging, T2WI; T2 fluid-attenuated inversion recovery, T2 FLAIR; and combinations of these sequences), to establish machine learning-based models for predicting the EGFR status of excised brain metastases (108 metastases for training and 54 metastases for testing). The least absolute shrinkage selection operator was used to select informative features; radiomics models were built with logistic regression of the training cohort, and model performance was evaluated using an independent test set.

Results

The best-performing model was a combination of 10 features selected from multiple sequences (two from T1CE, five from T2WI, and three from T2 FLAIR) in both the training and test sets, resulting in classification area under the curve, accuracy, sensitivity, and specificity values of 0.85 and 0.81, 77.8% and 75.9%, 83.7% and 73.1%, and 73.8% and 78.6%, respectively.

Conclusions

Radiomic signatures integrating multi-sequence MR images have the potential to noninvasively predict the EGFR mutation status of lung cancer brain metastases.

Resistance to TKIs in EGFR-Mutated Non-Small Cell Lung Cancer: From Mechanisms to New Therapeutic Strategies

Resistance to tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR) in advanced mutant Non-Small Cell Lung Cancer (NSCLC) constitutes a therapeutic challenge. This review intends to summarize the existing knowledge about the mechanisms of resistance to TKIs in the context of EGFR mutant NSCLC and discuss its clinical and therapeutic implications. EGFR-dependent and independent molecular pathways have the potential to overcome or circumvent the activity of EGFR-targeted agents including the third-generation TKI, osimertinib, negatively impacting clinical outcomes. CNS metastases occur frequently in patients on EGFR-TKIs, due to the inability of first and second-generation agents to overcome both the BBB and the acquired resistance of cancer cells in the CNS. Newer-generation TKIs, TKIs targeting EGFR-independent resistance mechanisms, bispecific antibodies and antibody-drug conjugates or combinations of TKIs with other TKIs or chemotherapy, immunotherapy and Anti-Vascular Endothelial Growth Factors (anti-VEGFs) are currently in use or under investigation in EGFR mutant NSCLC. Liquid biopsies detecting mutant cell-free DNA (cfDNA) provide a window of opportunity to attack mutant clones before they become clinically apparent. Overall, EGFR TKIs-resistant NSCLC constitutes a multifaceted therapeutic challenge. Mapping its underlying mutational landscape, accelerating the detection of resistance mechanisms and diversifying treatment strategies are essential for the management of the disease.

Systematic review and meta-analysis of lung cancer brain metastasis and primary tumor receptor expression discordance

BACKGROUND

Treatment paradigms for metastatic non-small cell lung cancer are increasingly based on biomarker-driven therapies, with the most common alteration being mutation in the epidermal growth factor receptor (EGFR). Change in expression of such biomarkers could have a profound impact on the choice and efficacy of a selected targeted therapeutic, and hence the objective of this study was to analyze discordance in EGFR status in patients with lung cancer brain metastasis (LCBM).

METHODS

Using PRISMA guidelines, a systematic review was performed of series in the Medline database of biopsied or resected LCBM published before May, 2020. Key words included "lung cancer" and "brain metastasis" combined with "epidermal growth factor receptor/EGFR," and "receptor conversion/discordance or concordance." Weighted random effects models were used to calculate pooled estimates.

RESULTS

We identified 501 patients from 19 full-text articles for inclusion in this study. All patients underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. On primary/LCBM comparison, the weighted pooled estimate for overall EGFR receptor discordance was 10% (95% CI 5-17%). The weighted effects model estimated a gain of an EGFR mutation in a brain metastases in patients with negative primary tumors was 7% (95% CI 4-12%). Alternatively, the weighted effects model estimate of loss of an EGFR mutation in patients with detected mutations in the primary tumor was also 7% (95% CI 4-10%). KRAS testing was also performed on both primary tumors and LCBM in a subset of 148 patients. The weighted effects estimate of KRAS-mutation discordance among LCBM compared to primary tumors was 13% (95% CI 5-27%). The weighted effects estimated of KRAS gain and loss in LCBM was 10% (95% CI 6-18%) and 8% (95% CI 4-15%), respectively. Meta-regression analysis did not find any association with any factors that could be associated with discordances.

CONCLUSIONS

EGFR and KRAS mutation status discordance between primary tumor and LCBM occurs in approximately 10% and 13% of patients, respectively. Evaluation of LCBM receptor status is key to biomarker-driven targeted therapy for intracranial disease and awareness of subtype switching is critical for those patients treated with systemic therapy alone for intracranial disease.

Prognostic Value of Combing Primary Tumor and Nodal Glycolytic-Volumetric Parameters of 18F-FDG PET in Patients with Non-Small Cell Lung Cancer and Regional Lymph Node Metastasis

We investigated whether the combination of primary tumor and nodal ¹⁸F-FDG PET parameters predict survival outcomes in patients with nodal metastatic non-small cell lung cancer (NSCLC) without distant metastasis. We retrospectively extracted pre-treatment ¹⁸F-FDG PET parameters from 89 nodal-positive NSCLC patients (stage IIB–IIIC). The Cox proportional hazard model was used to identify independent prognosticators of overall survival (OS) and progression-free survival (PFS). We devised survival stratification models based on the independent prognosticators and compared the model to the American Joint Committee on Cancer (AJCC) staging system using Harrell’s concordance index (c-index). Our results demonstrated that total TLG (the combination of primary tumor and nodal total lesion glycolysis) and age were independent risk factors for unfavorable OS (p < 0.001 and p = 0.001) and PFS (both p < 0.001), while the Eastern Cooperative Oncology Group scale independently predicted poor OS (p = 0.022). Our models based on the independent prognosticators outperformed the AJCC staging system (c-index = 0.732 versus 0.544 for OS and c-index = 0.672 versus 0.521 for PFS, both p < 0.001). Our results indicate that incorporating total TLG with clinical factors may refine risk stratification in nodal metastatic NSCLC patients and may facilitate tailored therapeutic strategies in this patient group.

Non-Small Cell Lung Cancer from Genomics to Therapeutics: A Framework for Community Practice Integration to Arrive at Personalized Therapy Strategies

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, and therapeutic management has advanced with the identification of various key oncogenic mutations that promote lung cancer tumorigenesis. Subsequent studies have developed targeted therapies against these oncogenes in the hope of personalizing therapy based on the molecular genomics of the tumor. This review presents approved treatments against actionable mutations in NSCLC as well as promising targets and therapies. We also discuss the current status of molecular testing practices in community oncology sites that would help to direct oncologists in lung cancer decision-making. We propose a collaborative framework between community practice and academic sites that can help improve the utilization of personalized strategies in the community, through incorporation of increased testing rates, virtual molecular tumor boards, vendor-based oncology clinical pathways, and an academic-type singular electronic health record system.

Tyrosine Kinase Inhibitors Could Be Effective Against Non-small Cell Lung Cancer Brain Metastases Harboring Uncommon EGFR Mutations

Background: The significance of uncommon epidermal growth factor receptor (EGFR) mutations in patients with non-small cell lung cancer (NSCLC) and brain metastasis (BM) remains unclear. Cerebrospinal fluid (CSF) liquid biopsy is a novel tool for assessing EGFR mutations in BM. This study aimed to evaluate the EGFR mutations in patients with NSCLC and newly diagnosed BM and to examine the effect of EGFR tyrosine kinase inhibitors (TKI) on BM harboring CSF-tested uncommon EGFR mutations.

Methods: This was a prospective study of 21 patients with NSCLC and BM diagnosed between 04/2018 and 01/2019. CSF was obtained to detect the BM EGFR mutations by next-generation sequencing. BM characteristics at magnetic resonance imaging (MRI) and EGFR-TKI response were examined.

Results: Of 21 patients with NSCLC, 10 (47.6%) had leptomeningeal metastasis (LM), while 11 (52.4%) had brain parenchymal metastasis (BPM); 13 (61.9%) had confirmed EGFR mutation-positive primary tumors. The uncommon mutation rate in CSF ctDNA was 33.3% (7/21). Among those with EGFR mutation-positive primary tumors, the rate of uncommon EGFR mutations in CSF was 53.8% (7/13). Uncommon EGFR mutations were more common in patients with LM than in patients with PBM (6/11, 54.5% vs. 1/10, 10%), and included G719A, L861Q, L703P, and G575R. TKI was effective for four patients with BMs harboring uncommon EGFR mutations.

Conclusion: In patients with NSCLC and LM, the rate of uncommon EGFR mutation was high. The BMs with uncommon EGFR mutations seem to respond to EGFR-TKI treatment. CSF liquid biopsy could reveal the EGFR genetic profile of the BM and help guide treatment using small-molecule TKI.

Discordance of epidermal growth factor receptor mutation between primary lung tumor and paired distant metastases in non-small cell lung cancer: A systematic review and meta-analysis

Purpose

To evaluate the rate of discordance of epidermal growth factor receptor (EGFR) mutation between primary lung tumor and paired distant metastases in non-small-cell lung cancer (NSCLC).

Methods

We performed a meta-analysis of 17 studies (518 cases) assessing discordance rates of EGFR mutation in primary tumors and paired distant metastases. We performed subgroup analyses based on EGFR mutation status in primary tumor (mutant or wildtype), site of distant metastasis (bone, central nervous system (CNS) or lung/ pleural), methods of testing (direct sequencing or allele-specific testing) and timing of metastasis (synchronous or metachronous).

Results

The overall discordance rate in EGFR mutation was low at 10.36% (95% CI = 4.23% to 18.79%) and varied widely between studies (I² = 83.18%). The EGFR discordance rate was statistically significantly higher in bone metastases (45.49%, 95% CI = 14.13 to 79.02) than CNS (17.26%, 95% CI = 7.64 to 29.74; P = 0.002) and lung/ pleural metastases (8.17%, 95% CI = 3.35 to 14.85; P < 0.001). Subgroup analyses did not demonstrate any significant effect modification on the discordance rates by the EGFR mutation status in primary lung tumor, methods of testing and timing of metastasis.

Conclusion

The overall discordance rate in EGFR mutation between primary lung tumor and paired distant metastases in NSCLC is low, although higher discordance rates were observed in bone metastases compared with CNS and lung/pleural metastases. Future studies assessing the impact of EGFR mutation discordance on treatment outcomes are required.

Risk factors for brain metastases in patients with non-small-cell lung cancer

Brain metastases (BM) are severe incidents in patients with non-small-cell lung cancer (NSCLC). The controversial value of prophylactic cranial irradiation (PCI) in NSCLC in terms of survival benefit prompted us to explore the possible risk factors for BM in NSCLC and identify the potential population most likely to benefit from PCI. Risk factors for brain metastases in NSCLC are reviewed in this article. Identifying patients with a higher risk of BM could possibly increase the benefit of PCI while reducing the discomfort and risks caused by unnecessary invasive procedures in the NSCLC patient population. Future studies might focus on finding a solid basis for the prediction of the occurrence of brain metastases and for the therapeutic decision on the use of PCI.

Mutational analysis on gastric, duodenal, bone, and mediastinal lymph node metastases and blood from a case of primary lung adenocarcinoma

Rapid metastasis contributes significantly to the high mortality rates in lung adenocarcinoma. The present study reports a rare case of primary lung adenocarcinoma with concomitant gastric, duodenal, bone, and mediastinal lymph node metastases. A large gene panel based on the next-generation sequencing was used to detect gene mutations in different metastatic sites and blood. The results showed that the gene mutation spectrums among different metastatic foci were roughly similar. The mutation abundance was highest in mediastinal lymph nodes. Unique mutation sites were detected only in mediastinal lymph nodes, bone, and gastric metastatic foci. Despite partial heterogeneity, there are currently no applicable targeted drugs to adopt. In addition, tumor mutation burden (TMB) showed that blood, gastric, bone, and mediastinal lymph node metastases were all TMB-High, while the duodenal metastasis was TMB-Low. This study is the first to report a rare case of newly diagnosed lung adenocarcinoma with concomitant gastrointestinal metastases and to perform mutation analyses on all metastatic foci. Large sample sizes with similar cases are required to gain deeper insights.

Management of Brain Metastases in Epidermal Growth Factor Receptor Mutant Non-Small-Cell Lung Cancer

Lung cancer remains a leading cause of mortality with 1.69 million deaths worldwide. Activating mutations in epidermal growth factor receptor (EGFR), predominantly exon 19 deletions and exon 21 L858R mutations, are known oncogenic drivers identified in 20-40% of non-small-cell lung cancers (NSCLC). 70% of EGFR-mutant NSCLC patients develop brain metastases (BM), compared to 38% in EGFR wild-type patients. First-generation tyrosine kinase inhibitors (TKIs), such as erlotinib and gefitinib have proven to be superior to chemotherapy in the front-line treatment of EGFR-mutant NSCLC, as has afatinib, a second-generation TKI. The most common acquired resistance mechanism is the development of a gatekeeper mutation in exon 20 T790M. Osimertinib has emerged as a third-generation EGFR TKI with proven activity in the front-line setting as well as in patients with a T790M acquired resistance mutation with remarkable CNS activity. As long-term survival outcomes in EGFR-mutant NSCLC continue to improve, the burden of BM becomes a greater challenge. Here, we review the literature related to the management of BM in EGFR-mutant NSCLC including the role of the three generations of EGFR TKIs, immunotherapy, and brain radiation.

Potential Molecular Signatures Predictive of Lung Cancer Brain Metastasis

Brain metastases are the most common tumors of the central nervous system (CNS). Incidence rates vary according to primary tumor origin, whereas the majority of the cerebral metastases arise from primary tumors in the lung (40-50%). Brain metastases from lung cancer can occur concurrently or within months after lung cancer diagnosis. Survival rates after lung cancer brain metastasis diagnosis remain poor, to an utmost of 10 months. Therefore, prevention of brain metastasis is a critical concern in order to improve survival among cancer patients. Although several studies have been made in order to disclose the genetic and molecular mechanisms associated with CNS metastasis, the precise mechanisms that govern the CNS metastasis from lung cancer are yet to be clarified. The ability to forecast, which patients have a higher risk of brain metastasis occurrence, would aid cancer management approaches to diminish or prevent the development of brain metastasis and improve the clinical outcome for such patients. In this work, we revise genetic and molecular targets suitable for prediction of lung cancer CNS disease.

A bispecific enediyne-energized fusion protein targeting both epidermal growth factor receptor and insulin-like growth factor 1 receptor showing enhanced antitumor efficacy against non-small cell lung cancer

Epidermal growth factor receptor (EGFR) and insulin-like growth factor 1 receptor (IGF-1R) both overexpressed on non-small cell lung cancer (NSCLC) and are known cooperatively to promote tumor progression and drug resistance. This study was to construct a novel bispecific fusion protein EGF-IGF-LDP-AE consisting of EGFR and IGF-IR specific ligands (EGF and IGF-1) and lidamycin, an enediyne antibiotic with potent antitumor activity, and investigate its antitumor efficacy against NSCLC. Binding and internalization assays showed that EGF-IGF-LDP protein could bind to NSCLC cells with high affinity and then internalized into cells with higher efficiency than that of monospecific proteins. In vitro, the enediyne-energized analogue of bispecific fusion protein (EGF-IGF-LDP-AE) displayed extremely potent cytotoxicity to NSCLC cell lines with IC₅₀<10⁻¹¹ mol/L. Moreover, the bispecific protein EGF-IGF-LDP-AE was more cytotoxic than monospecific proteins (EGF-LDP-AE and LDP-IGF-AE) and lidamycin. In vivo, EGF-IGF-LDP-AE markedly inhibited the growth of A549 xenografts, and the efficacy was more potent than that of lidamycin and monospecific counterparts. EGF-IGF-LDP-AE caused significant cell cycle arrest and it also induced cell apoptosis in a dosage-dependent manner. Pretreatment with EGF-IGF-LDP-AE inhibited EGF-, IGF-stimulated EGFR and IGF-1R phosphorylation, and blocked two main downstream signaling molecules AKT and ERK activation. These data suggested that EGF-LDP-IGF-AE protein would be a promising targeted agent for NSCLC patients with EGFR and/or IGF-1R overexpression.

Clinical Characteristics and Survival Outcomes for Non-Small-Cell Lung Cancer Patients with Epidermal Growth Factor Receptor Double Mutations

Multiple randomized clinical trials have demonstrated that epidermal growth factor receptor (EGFR) exon 19 deletion (19Del) and exon 21 L858R mutation (L858R) are highly correlated with sensitivity to epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment in non-small-cell lung cancer (NSCLC). A mutation in exon 20 (T790M) is reportedly associated with resistance to EGFR-TKIs. However, few studies have focused on patients harboring double mutations in these 3 mutation sites. In this retrospective study, forty-five patients (45/2546, 1.7%) harbored double mutations of 19Del, L858R, and T790M. Twenty-four patients with EGFR double mutations received EGFR-TKI therapy. Clinical characteristics of these patients, including the response to EGFR-TKIs and progression-free survival outcome for EGFR-TKI treatment (PFS-TKI), were analyzed. Patients with EGFR double mutations were more likely to be nonsmokers, have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-1, have adenocarcinoma, and be at stage III-IV. The ORR, DCR, and median PFS-TKI in patients harboring EGFR double mutations were lower than in patients with a single EGFR-activating mutation. The differences in ORR and DCR were statistically insignificant between the 3 groups. Patients with double mutations of 19Del and T790M had longer PFS-TKIs than patients in the other 2 groups.

Leptomeningeal metastasis from systemic cancer: Review and update on management

Leptomeningeal metastasis is an uncommon and typically late complication of cancer with a poor prognosis and limited treatment options. Diagnosis is often challenging, with nonspecific presenting symptoms ranging from headache and confusion to focal neurologic deficits, such as cranial nerve palsies. Standard diagnostic evaluation involves a neurologic examination, magnetic resonance imaging of the brain and spine with gadolinium, and cytologic evaluation of the cerebral spinal fluid. Therapy entails a multimodal approach focused on palliation with surgery, radiation, and/or chemotherapy, which may be administered systemically or directly into the cerebral spinal fluid. Limited trial data exist to guide treatment, and current regimens are based primarily on expert opinion. Although newer targeted and immunotherapeutic agents are under investigation and have shown promise, an improved understanding of the biology of leptomeningeal metastasis and treatment resistance as well as additional randomized controlled studies are needed to guide the optimal treatment of this devastating disease. Cancer 2018;124:21-35. © 2017 American Cancer Society.

Lung cancer-associated brain metastasis: Molecular mechanisms and therapeutic options

BACKGROUND

Lung cancer is the most common cause of cancer-related mortality in humans. There are several reasons for this high rate of mortality, including metastasis to several organs, especially the brain. In fact, lung cancer is responsible for approximately 50% of all brain metastases, which are very difficult to manage. Understanding the cellular and molecular mechanisms underlying lung cancer-associated brain metastasis brings up novel therapeutic promises with the hope to ameliorate the severity of the disease. Here, we provide an overview of the molecular mechanisms underlying the pathogenesis of lung cancer dissemination and metastasis to the brain, as well as promising horizons for impeding lung cancer brain metastasis, including the role of cancer stem cells, the blood-brain barrier, interactions of lung cancer cells with the brain microenvironment and lung cancer-driven systemic processes, as well as the role of growth factor/receptor tyrosine kinases, cell adhesion molecules and non-coding RNAs. In addition, we provide an overview of current and novel therapeutic approaches, including radiotherapy, surgery and stereotactic radiosurgery, chemotherapy, as also targeted cancer stem cell and epithelial-mesenchymal transition (EMT)-based therapies, micro-RNA-based therapies and other small molecule or antibody-based therapies. We will also discuss the daunting potential of some combined therapies.

CONCLUSIONS

The identification of molecular mechanisms underlying lung cancer metastasis has opened up new avenues towards their eradication and provides interesting opportunities for future research aimed at the development of novel targeted therapies.

EGFR copy number alterations in primary tumors, metastatic lymph nodes, and recurrent and multiple primary tumors in oral cavity squamous cell carcinoma

Background

The EGFR and downstream signaling pathways play an important role in tumorigenesis in oral squamous cell carcinoma (OSCC). Gene copy number alteration is one mechanism for overexpressing the EGFR protein and was also demonstrated to be related to lymph node metastasis, tumor invasiveness and perineural invasion. Therefore, we hypothesized that EGFR gene copy number alteration in the primary tumor could predict amplification in recurrent tumors, lymph node metastatic foci or secondary primary tumors.

Methods

We recruited a group of newly diagnosed OSCC patients (n = 170) between Mar 1997 and Jul 2004. Metastatic lymph nodes were identified from neck dissection specimens (n = 57). During follow-up, recurrent lesions (n = 41) and secondary primary tumors (SPTs, n = 17) were identified and biopsied. The EGFR gene amplifications were evaluated by fluorescence in situ hybridization (FISH) assay in primary tumors, metastatic lymph nodes, recurrences and SPTs.

Results

Of the 170 primary OSCCs, FISH showed low EGFR amplification/polysomy in 19 (11.4%) patients and amplification in 33 (19.8%) patients. EGFR gene amplification was related to lymph node metastasis (χ2 trend test: p = 0.018). Of 57 metastatic lymph nodes, nine (15.8%) had EGFR polysomy and 14 (24.6%) had EGFR gene amplification. The concordance rate of EGFR gene copy number in primary tumors and lymph node metastasis was 68.4% (McNemar test: p = 0.389). Of 41 recurrent tumors, five (12.2%) had EGFR polysomy and five (12.2%) had gene amplification. The concordance rate of EGFR gene copy number between primary tumors and recurring tumors was 65.9% (McNemar test: p = 0.510). The concordance rate between primary tumors and SPTs was 70.6%. EGFR amplification in either primary tumors, metastatic lymph nodes or recurrent tumors had no influence on patient survival.

Conclusion

We can predict two-thirds of the EGFR gene copy number alterations in lymph node metastasis or recurrent tumors from the analysis of primary tumors. For OSCC patients who are unable to provide lymph node or recurrent tumor samples for EGFR gene copy number analysis, examining primary tumors could provide EGFR clonal information in metastatic, recurrent or SPT lesions.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3586-9) contains supplementary material, which is available to authorized users.

The effectiveness of EGFR-TKIs against brain metastases in EGFR mutation-positive non-small-cell lung cancer

Brain metastases are usual in non-small-cell lung cancer (NSCLC) with poor prognosis and few available therapeutic options. This retrospective study aims to evaluate the efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) against brain metastases from NSCLC harboring activating EGFR mutation. A total of 148 patients with brain metastases from EGFR mutation-positive NSCLC were analyzed retrospectively. The patients were orally given gefitinib (250 mg) or erlotinib (150 mg) once a day until intracranial disease progression, death, or intolerable side effects. A survival analysis was done using the Kaplan–Meier analysis and log-rank test. Objective response rate and disease control rate within brain lesions were 36.5% and 87.2%, respectively, with a median progression-free survival (PFS) and overall survival (OS) of 11.2 months (95% confidence interval [CI], 10.1–12.3) and 13.6 months (95% CI, 12.3–14.9), respectively. The patients’ characteristics were not statistically associated with PFS and OS. EGFR-TKIs showed promising antitumor activity against brain metastases in NSCLC patients with activating EGFR mutation and might be the treatment choice in this clinical setting.

Baseline neutrophil-lymphocyte ratio is associated with baseline and subsequent presence of brain metastases in advanced non-small-cell lung cancer

We examined the predictive value of neutrophil–lymphocyte ratio (NLR) by examining their association with the baseline presence and subsequent development of brain metastases in patients with stage IV non-small cell lung cancer (NSCLC). We examined the predictive value of NLR for brain metastasis in 260 stage IV NSCLC. Logistic regression models and competing risk analysis were used to determine the association of NLR with baseline and subsequent presence of brain metastases. Multivariate analysis reveals that patients with high NLR (≥4.95) had significantly more brain metastases at diagnosis than those with low NLR (Odds Ratio = 2.59, P = 0.01). In patients who had no baseline brain metastasis, competing risks analysis revealed that patients with high NLR showed higher cumulative incidence of subsequent brain metastases, compared to those with low NLR (P = 0.017). A high NLR was associated with the baseline presence or the subsequent development of brain metastases, particularly in the group with adenocarcinoma (P = 0.013 and P = 0.044, respectively). Furthermore, an increase in NLR during treatment was associated with subsequent brain metastases (P = 0.004). The NLR is an independent predictive factor for the baseline presence of brain metastases and subsequent brain metastases in stage IV NSCLC.

Lung Carcinoma Staging Update

Context.—

The International Association for the Study of Lung Cancer Staging Committee has prospectively created an international lung cancer database that was used to address many lung cancer staging questions, such as tumor size, nodal status, and metastatic disease. The proposed changes for the upcoming 8th edition of the cancer staging manual were based on survival data and better prognostic stratification of patients with lung cancer.

Objectives.—

To review published recommendations for the revision of lung carcinoma TNM staging and to address potential challenges in pathologic staging.

Data Source.—

PubMed available articles by the International Association for the Study of Lung Cancer Staging Committee were reviewed.

Conclusions.—

The TNM system remains the best prognosticator of lung cancer outcome. The recommendations are established on new prospective data analysis and reflect the improvements in prognostic separation of patients with lung cancer based on a multidisciplinary approach.

The Challenges of Validating in Precision Medicine: The Case of Excision Repair Cross-Complement Group 1 Diagnostic Testing

Personalized medicine relies upon the successful identification and translation of predictive biomarkers. Unfortunately, biomarker development has often fallen short of expectations. To better understand the obstacles to successful biomarker development, we systematically mapped research activities for a biomarker that has been in development for at least 12 years: excision repair cross-complement group 1 protein (ERCC1) as a biomarker for predicting clinical benefit with platinum-based chemotherapy in non-small cell lung cancer. We found that although research activities explored a wide range of approaches to ERCC1 testing, there was little replication or validation of techniques, and design and reporting of results were generally poor. Our analysis points to problems with coordinating and standardizing research in biomarker development. Clinically meaningful progress in personalized medicine will require concerted efforts to address these problems. In the interim, health care providers should be aware of the complexity involved in biomarker development, cautious about their near-term clinical value, and conscious of applying only validated diagnostics in the clinic.

THE ONCOLOGIST

2017;22:89-96 IMPLICATIONS FOR PRACTICE: : Many hospitals, policy makers, and scientists have made ambitious claims about the promise of personalizing cancer care. When one uses a case example of excision repair cross-complement group 1 protein-a biomarker that has a strong biological rationale and that has been researched for 12 years-the current research environment seems poorly suited for efficient development of biomarker tests. The findings provide grounds for tempering expectations about personalized cancer care-at least in the near term-and shed light on the current gap between the promise and practice of personalized medicine.

Morphological and molecular approach to synchronous non-small cell lung carcinomas: impact on staging

Distinction between multiple primary cancers and intrapulmonary metastases in patients with synchronous multifocal lung cancer can be challenging. Histological and genotypic assessment of multifocal lung tumors have been suggested to influence the staging. The aim of this study was to determine the role of morphology and genotype in staging of surgically treated multifocal non-small cell lung carcinoma. Synchronous lung cancers from 60 patients (42 with adenocarcinoma and 18 with squamous cell carcinoma), clinically considered to represent intrapulmonary metastases, were histologically subtyped according to the 2015 World Health Organization classification of lung tumors and subjected to genotypic analysis (KRAS, EGFR, BRAF, PIK3CA, ALK, MET and ROS1 in adenocarcinoma and PIK3CA and p16 in squamous cell carcinoma). Concordance between clinical criteria and histological subtyping was identified in about 50% of cases (P<0.0001). Genotypically, 44% of adenocarcinomas and 60% of squamous cell carcinomas with identified molecular alterations were considered to be intrapulmonary metastases. Concordance between histological and molecular staging was observed in 89% of adenocarcinomas and 56% of squamous cell carcinomas. Univariate survival analyses failed to demonstrate significant differences in overall or cancer-specific survival in patients with adenocarcinoma and squamous cell carcinomas restaged according to histology and/or molecular profile. Lymph node metastases (N1/N2 vs N0) (P=0.03) and age >65 years (P=0.05) were associated with shorter overall survival. In addition, squamous cell carcinomas with p16 deletion showed shorter overall survival when compared with squamous cell carcinomas without p16 deletion (P=0.05). No correlation between other molecular alterations, clinico-pathological characteristics and prognosis was found. Our study demonstrates that a comprehensive genotypic and morphological assessment of surgically treated multifocal lung cancers is feasible but not sufficient to establish their clonal relationship and prognosis.

Heterogeneity of EGFR Aberrations and Correlation with Histological Structures: Analyses of Therapy-Naive Isogenic Lung Cancer Lesions with EGFR Mutation

INTRODUCTION

EGFR gene somatic mutation is reportedly homogeneous. However, there are few data regarding the heterogeneity of expression of mutant EGFR protein and EGFR gene copy number, especially in extrathoracic lesions. These types of data may enhance our understanding of the biology of EGFR-mutated lung cancer and our understanding of the heterogeneous response patterns to EGFR TKIs.

METHODS

An 81-year-old never-smoking female with lung adenocarcinoma could not receive any systemic therapy because of her poor performance status. After her death, 15 tumor specimens from different sites were obtained by autopsy. Expression of mutant EGFR protein and EGFR gene copy numbers were assessed by immunohistochemical analysis and by silver in situ hybridization, respectively. Heterogeneity in these EGFR aberrations was compared between metastatic sites (distant versus lymph node) or histological structures (micropapillary versus nonmicropapillary).

RESULTS

All lesions showed positive staining for mutant EGFR protein, except for 40% of the papillary component in one of the pulmonary metastases (weak staining below the 1+ threshold). Expression of mutant-specific EGFR protein, evaluated by H-score, was significantly higher in the micropapillary components than in the nonmicropapillary components (Mann-Whitney U test, p = 0.014). EGFR gene copy number was quite different between lesions but not correlated with histological structure or metastatic form. However, EGFR gene copy numbers were similar between histological structures in each lesion.

CONCLUSION

These data indicate that expression of EGFR mutant protein and EGFR gene copy number do not change as a consequence of tumor progression. This also justifies using the biopsy specimens from metastases as a surrogate for primary tumors.

Radiotherapy plus EGFR TKIs in non-small cell lung cancer patients with brain metastases: an update meta-analysis

Brain metastasis (BM) is the common complication of non‐small cell lung cancer (NSCLC) with a poor prognosis and dismal survival rate. This update meta‐analysis aimed to derive a more precise estimation of radiotherapy plus epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in NSCLC patients with BM. PubMed, EMBASE, Web of Science, Google Scholar, and Cochrane Library were searched to identify any relevant publications. After screening the literature and undertaking quality assessment and data extraction, the meta‐analysis was performed using STATA Version 12.0. In total, 15 studies involving 1552 participants were included. The results indicated that radiotherapy plus EGFR TKIs was more effective at improving response rate and disease control rate (DCR) (risk ratio (RR) = 1.48, 95% confidence interval [CI]: 1.12–1.96, P = 0.005; RR = 1.29, 95% CI: 1.02–1.60, P = 0.035; respectively) than radiotherapy alone or plus chemotherapy. Moreover, radiotherapy plus EGFR TKIs significantly prolonged the time to central nervous system progression (CNS‐TTP) (HR = 0.56, 95% CI [0.33, 0.80]; P = 0.000) and median overall survival (OS) (HR = 0.58, 95% CI [0.42, 0.74]; P = 0.000) but significantly increased adverse events (any grade) (RR = 1.25, 95% CI [1.01, 1.57]; P = 0.009), especially rash and dry skin. These results suggested that radiotherapy plus EGFR TKIs produced superior response rate and DCR and markedly prolonged the CNS‐TTP and OS of NSCLC patients with BM. However, combined groups had the higher rate of incidence of overall adverse effects, especially rash and dry skin.

Serum Biomarkers Associated with Clinical Outcomes Fail to Predict Brain Metastases in Patients with Stage IV Non-Small Cell Lung Cancers

Background

Lung cancers account for the majority of brain metastases which pose major therapeutic challenges. Biomarkers prognosticating for the development of brain metastases in patients with non-small cell lung cancers (NSCLC) may improve personalized care. Six serum proteomic biomarkers were previously investigated at Memorial Sloan Kettering but their associations with brain metastases were unknown.

Methods

Serum NSE, CYFRA 21–1, ProGRP, SCC-Ag, TIMP1, and HE4 by ELISA-based proteomic assays were prospectively collected from consecutive patients with stage IV NSCLC. Pre-treatment serum biomarker levels as well as age, histology, and epidermal growth factor receptor (EGFR) mutation status were evaluated for association with the baseline presence of brain metastases using logistic regression and multivariable analysis. For patients without brain metastases at baseline, the cumulative incidence of subsequent brain metastases were compared according to baseline biomarkers and clinical factors using Gray’s test.

Results

A total of 118 patients were enrolled, 31 (26%; 95% CI 0.19–0.35) had brain metastases at baseline and a further 26 (22%; 95% CI 0.15–0.30) developed brain metastases subsequently. Pre-treatment serum biomarker levels were available in 104 patients. There was no significant association between the six serum biomarkers and the baseline presence or subsequent development of brain metastases. Age younger than 65 years was the only clinical factor significantly associated with brain metastasis at baseline (OR 3.00; 95% CI 1.22–7.34, P = 0.02) by multivariable analysis. A trend toward increased cumulative incidence of subsequent brain metastases was observed in patients with EGFR mutation (p = 0.2), but this was not statistically significant possibly due to small sample size.

Conclusions

Serum NSE, CYFRA 21–1, Pro-GRP, SCC-Ag, TIMP1, and HE4 are not significantly associated with brain metastases. Our methods taking into account follow-up time may be applied to independent datasets to identify a patient cohort with a higher biologic propensity for developing brain metastases. Such information may be useful for the study of agents targeting the development of brain metastases.

[Research Progress of Mechanisms on Intracranial Metastasis of Non-small Cell Lung Cancer after Clinical Benefit from EGFR-TKI]

表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitor, EGFR-TKI）广泛用于治疗EGFR突变阳性的非小细胞肺癌（non-small cell lung cancer, NSCLC）。然而，部分患者在接受EGFR-TKI治疗后、原发病灶稳定甚至缩小的同时，却出现了新发颅内转移灶或者原有颅内病灶进展，其机制未明。近年来多项研究表明，这种现象可能与EGFR-TKI的药物代谢动力学、NSCLC原发灶与转移灶的异质性、EGFR突变本身特质及患者生存期的延长有关。因此，本文就NSCLC患者在EGFR-TKI治疗临床获益后发生颅内转移的相关机制研究进展作一综述。

Comparison of epidermal growth factor receptor mutations between primary tumors and lymph nodes in non-small cell lung cancer: a review and meta-analysis of published data

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) can predict the clinical response to tyrosine kinase inhibitor (TKI) therapy. However, EGFR mutations may be different in primary tumors (PT) and metastatic lymph nodes (MLN). The aim of this study was to compare EGFR mutations between PT and the corresponding MLN in NSCLC patients, and provide some guidelines for clinical treatment using TKI therapy.

MATERIALS AND METHODS

A systematic review and meta-analysis was performed with several research databases. Relative risk (RR) with the 95% confidence interval (CI) were used to investigate the EGFR mutation status between PT and the corresponding MLN. A random-effects model was used.

RESULTS

9 publications involving 707 patients were included in the analysis. It was found that activation of EGFR mutations identified in PT and the corresponding MLN was 26.4% (187/707) and 19.9% (141/707), respectively. The overall discordance rate in our meta-analysis was 12.2% (86/707). The relative risk (RR) for EGFR mutation in PT relative to MLN was 1.33 (95%CI: 1.10-1.60; random-effects model). There was no significant heterogeneity between the studies (I2=5%, p=0.003).

CONCLUSIONS

There exists a considerable degree of EGFR mutation discrepancy in NSCLC between PT and corresponding MLN, suggesting that tumor heterogeneity might arise at the molecular level during the process of metastasis.

EGFR tyrosine kinase inhibitors versus cranial radiation therapy for EGFR mutant non-small cell lung cancer with brain metastases: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

EGFR TKIs alone have demonstrated activity against intracranial disease in EGFR mutant non-small cell lung cancer (NSCLC). This study aimed to determine if upfront cranial radiotherapy improves intracranial disease control and survival outcomes in EGFR mutant NSCLC with brain metastases relative to TKIs alone.

MATERIALS AND METHODS

We searched MEDLINE and various conference proceedings from 2008 to July 2014 for eligible studies where patients received upfront cranial radiotherapy or TKIs alone. Outcomes of interest were overall intracranial disease response rate (ORR), four-month intracranial disease progression-free survival (PFS), two-year overall survival (OS) and neurological adverse events (AE). We used random effects models to pool outcomes across studies and compared them using interaction tests.

RESULTS

We found 12 non-comparative observational studies (n=363) with severe methodological limitations. Upfront cranial radiotherapy results in similar intracranial disease ORR (relative risk (RR) 0.93, 95% confidence interval (CI) 0.82-1.06; interaction p value (p)=0.53), improved four-month intracranial disease PFS (RR 1.06, 95% CI 1.00-1.12; p=0.03), improved two-year OS (RR 1.33, 95% CI 1.00-1.77; p=0.05) but caused more neurological AEs than TKIs alone.

CONCLUSION

There is evidence, albeit of low quality, that upfront cranial radiotherapy may improve intracranial disease control and survival outcomes compared with TKI alone.

Clinicopathological features and outcome of gastric metastases from primary lung cancer: A case report and systematic review

Primary lung cancer is the fourth most frequently diagnosed cancer, but gastric metastasis from lung cancer is extremely rare. Little is known about its clinicopathological features, prognosis and optimal treatment strategy. The present study reports a case of primary lung cancer that metastasized to the stomach and to the best of our knowledge, is the first to identify discordance in epidermal growth factor receptor (EGFR) mutation status between the primary tumor and gastric metastasis. The study also systematically searched the Medline database for similar cases to provide a literature review. Data concerning the clinicopathological features, treatment strategies and outcomes were extracted and analyzed. In total, 22 eligible cases were identified from 16 studies. The average age at presentation was 67.3 years and there was a male predominance of 90.9%. Epigastric pain (45.5%) was the most common chief complaint, followed by melena (22.7%), nausea/vomiting (13.6%) and hematemesis (9.1%). Three patients were asymptomatic. Five patients sought the initial consultation for gastrointestinal symptoms. The median time between the primary lung cancer diagnosis and the confirmation of gastric metastasis was five months. Endoscopically, gastric lesions were described as polypoid masses or volcano-like ulcers, mostly involving the gastric corpus, which were identified in 62.5% of the 16 cases in which information regarding the site of metastasis was available. Gastric metastases were reported from adenocarcinoma, squamous cell carcinoma, small cell lung cancer and pleomorphic carcinoma of the lung. The median survival following comprehensive treatment strategies was four months, and the one-year post-metastasis survival rate was 35.3%. In conclusion, although primary lung cancer metastasis to the stomach is rare, clinicians should be aware of the possibility of its occurrence. Comprehensive and personalized treatment may be beneficial to patients. EGFR tyrosine-kinase inhibitor therapy may be the treatment of choice for non-small cell lung carcinoma patients harboring an activating EGFR mutation in the metastatic lesion.

Meta-analysis of epidermal growth factor receptor and KRAS gene status between primary and corresponding metastatic tumours of non-small cell lung cancer

The epidermal growth factor receptor (EGFR) and KRAS gene status in paired primary non-small cell lung cancer (NSCLC) and metastatic tumours has been investigated by many studies, but remains controversial. We systematically reviewed studies in English of EGFR and KRAS gene status in primary and corresponding metastatic NSCLC up to 15 January 2014. Studies were selected rigorously from PubMed, EMBASE, as well as Cochrane Library databases. We carried out a meta-analysis to clarify EGFR mutations, EGFR amplification, positive rate of EGFR protein expression and KRAS mutations in primary and corresponding metastatic NSCLC. Our data suggested that the overall EGFR mutation rate, gene copy number, protein expression were not different between primary tumours and corresponding metastases, with the pooled odd ratios and 95% confidence interval 1.043 (0.686-1.586, P = 0.844), 0.604 (0.355-1.027, P = 0.063) and 1.447 (0.948-2.208, P = 0.087), respectively. The overall KRAS mutation rate of primary tumours was not different from that of matched metastases, with the odds ratio and 95% confidence interval being 1.224 (0.808-1.856, P = 0.340). The discordant rates of EGFR and KRAS mutations in paired primary and metastatic NSCLC were 14.5 and 16.7%, respectively. Among the discordant gene mutations in primary and metastatic lesions, the frequency of occurrence of mutation was not different from the frequency of loss of mutation for EGFR (P = 0.093) and KRAS gene (P = 0.227). These results indicate that EGFR and KRAS mutations are present frequently in metastases and occur before metastasis. Therefore, routine analysis of EGFR or KRAS gene status both in primary and metastatic tumours is not recommended.

Cyclin D1 gene amplification is highly homogeneous in breast cancer

BACKGROUND

Cyclin D1 (CCND1) gene amplification is a molecular key alteration in breast cancer and was suggested to predict resistance to antihormonal therapy. As tissue heterogeneity may affect diagnostic accuracy of predictive biomarkers, CCND1 genetic heterogeneity was assessed in this study. A novel tissue microarray (TMA) platform was manufactured for this purpose.

METHODS

Primary breast carcinomas from 147 patients were sampled in a "heterogeneity-TMA" by taking eight different tissue cores from 4 to 8 tumor-containing blocks per case. Additional tissue samples were taken from 1 to 4 corresponding nodal metastases in 35 of these patients. CCND1 amplification was assessed by fluorescence in situ hybridization (FISH).

RESULTS

CCND1 amplification was seen in 28 of 133 (21.05 %) informative patients. Amplification was significantly associated with high tumor grade (p = 0.042), but unrelated to tumor type (p = 0.307), stage (p = 0.540) and ER (p = 0.061) or PR (p = 0.871) expression. A discordant Cyclin D1 amplification status was detected in 6 out of 28 (21.43 %) amplified tumors by heterogeneity-TMA analysis. Re-testing on large sections revealed three patients with true heterogeneity of high-level CCND1 amplification and another three patients with variable interpretation of borderline FISH ratios ranging between 1.7 and 2.3. No discrepancies were detected between 22 primary tumors and their matched lymph node metastases.

CONCLUSIONS

The high degree of homogeneity seen for CCND1 amplification suggests that this alteration is an early event in the development of a small subset of breast cancers.

Epidermal growth factor receptor tyrosine kinase inhibitors in the treatment of central nerve system metastases from non-small cell lung cancer

Brain metastases (BM) are common and disastrous occurrence in patients with non-small cell lung cancer (NSCLC). Currently increasing studies suggest remarkable efficacy and mild toxicity of the epidermal growth factor tyrosine kinase inhibitor (EGFR TKI) in these patients, making targeted therapy an attractive option to BM from NSCLC. We here present a review about the use of EGFR-TKIs in this context and the following questions would be discussed: Are TKIs capable of permeating across brain-blood barrier (BBB)? How to boost exposure of EGFR TKI in cerebrospinal fluid to overcome the resistance of refractory metastases? Would the combination with other treatment like radiotherapy bring about advanced effect? And which patients with BM is the fittest population to EGFR-TKI treatment? In fact, though the administration of EGFR TKI only could achieve certain effect with limited penetration across BBB, increasing dose and combined radiotherapy would carry out better outcome. Unsurprisingly EGFR mutations were still the most important predictor of the sensitivity.

EGFR mutation status and its impact on survival of Chinese non-small cell lung cancer patients with brain metastases

Brain metastasis (BM) is a leading cause of death in patients with non-small cell lung cancer (NSCLC). EGFR mutations in primary NSCLC lesions have been associated with sensitivity to EGFR tyrosine kinase inhibitor (TKI). Therefore, it has become important to understand EGFR mutation status in BM lesions of NSCLC, and its clinical implications. BM samples of 136 NSCLC patients from South China, in which 15 had paired primary lung tumors, were retrospectively analyzed for EGFR mutation by amplification mutation refractory system (ARMS). Effect of BM EGFR mutations on progression-free survival (PFS) and overall survival (OS) was evaluated by Kaplan-Meier curves and log-rank test. EGFR mutations were detected in 52.9% (72 of 136) of the BM lesions, with preference in female and never-smokers. A concordance rate of 93.3% (14 of 15) was found between the primary NSCLC and corresponding BM. Positive prediction value of testing primary NSCLCs for BM EGFR mutation is 100.0 %, and negative prediction value is 87.5%. Median PFS of BM surgery was 12 and 10 months (P = 0.594) in the wild-type and mutant group, respectively. Median OS of BM surgery was 24.5 and 15 months (P = 0.248) in the wild-type and mutant group, respectively. In conclusion, EGFR mutation status is highly concordant between the primary NSCLC and corresponding BM. The primary NSCLC could be used as surrogate samples to predict EGFR mutation status in BM lesions or vice versa. Moreover, EGFR mutations showed no significant effect on PFS or OS of NSCLCs with BM.

New frontiers in circulating tumor cell analysis: A reference guide for biomolecular profiling toward translational clinical use

Circulating tumor cells (CTCs) are now routinely isolated from blood, and measurement of CTC concentrations appears to correlate well with survival in patients with cancer. Interrogation of the molecular profile of CTCs for expression of protein biomarkers, genetic variants and gene expression provides opportunities to use this information to guide personalized treatment, monitor therapy and detect emerging resistance. However, successful application of profiling techniques requires analyses that deliver a reliable and clinically relevant representation of a patient's cancer as it changes with time. Here, we comprehensively review the current knowledge of therapeutically relevant biomarkers in isolated CTCs obtained by fluorescence imaging and genomic profiling approaches. The reviewed data support the notion that molecular profiling of CTCs will provide a reliable representation or surrogate index of tumor burden. Large-scale translational trials, many currently in progress, will provide critical data to progress CTC analysis toward wider clinical use in personalized treatment.

Neuropathology of brain metastases

Metastatic tumors are the most common neoplasms encountered in the central nervous system (CNS), and continue to be major cause for mortality and morbidity. Macroscopic features and corresponding radiological findings can be diagnostic in majority of the cases, however, microscopic evaluation would be necessary when the differential diagnosis includes a primary CNS tumor, unknown primary tumor site, and when the resection of the tumor is either considered therapeutic or palliative. The first step in the diagnosis of a metastatic brain lesion is to exclude a primary CNS tumor, followed by verification or identification of the primary tumor and the site. Although general approach to a metastatic lesion from an unknown primary tumor is the same everywhere else, there are slight variations for the metastatic lesions in the CNS versus other regions. When morphological features are not enough to establish a definitive diagnosis, additional studies including immunohistochemical stains are applied. With the expending immunohistochemical armamentarium for pathologists, more accurate assessments are possible even in cases of unknown primary tumor. This review summarizes the diagnostic approach to CNS metastases, immunohistochemical assessment of neoplasm of unknown primary, and primary CNS lesions entering in the differential diagnosis of metastases.

EGFR, KRAS, BRAF, and HER-2 molecular status in brain metastases from 77 NSCLC patients

The aim of this study was to determine the frequency of EGFR, KRAS, BRAF, and HER-2 mutations in brain metastases from non-small cell lung carcinomas (BM-NSCLC). A total of 77 samples of BM-NSCLC were included and 19 samples of BM from breast, kidney, and colorectal tumors were also studied as controls. These samples were collected from patients followed between 2008 and 2011 at Poitiers and Nice University Hospitals in France. The frequencies of EGFR, KRAS, BRAF, and HER-2 mutations in BM-NSCLC were 2.6, 38.5, 0, and 0% respectively. The incidence of KRAS mutation was significantly higher in female and younger patients (P < 0.05). No mutations of the four genes were found in BM from breast or kidney. However, among six BM from colorectal tumors, we identified KRAS mutations in three cases and BRAF mutations in two other cases. This study is the largest analysis on genetic alterations in BM-NSCLC performed to date. Our results suggest a low frequency of EGFR mutations in BM-NSCLC whereas KRAS mutations are as frequent in BM-NSCLC as in primitive NSCLC. These results raise the question of the variability of the brain metastatic potential of NSCLC cells in relation to the mutation pattern.

The molecular genomics of metastatic brain tumours

INTRODUCTION

Metastatic brain tumours remain an intractable clinical problem despite notable advances in the treatment of the primary cancers. It is estimated that 30-40% of breast and lung cancer patients will develop brain metastases. Typically, brain lesions are not diagnosed until patients exhibit neurological symptoms because there are currently no tests that can predict which patients will be afflicted. Brain metastases are resistant to current chemotherapies, and despite surgical resection and radiotherapy, the prognosis for these patients remains very poor with an average survival of only 6-9 months. Cancer is ultimately a genetic disease, involving patient genetics and aberrant tumour genomics; therefore the pursuit of an explanation for why or how brain metastases occur requires investigation of the associated somatic mutations. In this article, we review the current literature surrounding the molecular and genome-based mechanistic evidence to indicate driver oncogenes that hold potential biomarkers for risk, or therapeutic targets for treatment of brain metastases.

CONCLUSION

Patients afflicted with metastatic brain tumours are in dire need of more effective therapies, and clinicians need predictive laboratory tests to identify patients at risk of developing metastatic brain tumours. The as yet unrealized comprehensive analysis of metastatic brain tumour genomics is necessary to meet these needs. Moreover, without improved understanding of the genomic aberrations that drive metastatic brain tumours, development of biomarkers and molecularly targeted therapies will remain stalled and patient outcomes will continue to be dismal.

Erlotinib induced trichomegaly of the eyelashes

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been widely used for non-small-cell lung cancer patients. Its untoward cutaneous effects are largely well known and developed in many patients treated with EGFR TKIs. However trichomegaly of eyelash is rarely reported. Although trichomegaly is not a drug-limiting side effect, it could be troublesome of continuing the treatment because of cosmetic issue or eyeball irritation by long eyelashes. Therefore clinicians are needed to pay attention to this uncommon effect. We herein describe erlotinib induced trichomegaly of eyelashes in a woman with adenocarcinoma of the lung.

Frequent intratumoral heterogeneity of EGFR gene copy gain in non-small cell lung cancer

Next to EGFR mutation, EGFR gene copy number evaluated by fluorescence in situ hybridization (FISH) emerged as a potential predictive marker for sensitivity to EGFR tyrosine kinase inhibitors, although controversial data exist. As the diagnostic accuracy of predictive biomarkers can be substantially limited by regional differences within tumors, heterogeneity of EGFR gene copy gain in NSCLC was assessed in this study. For this purpose, a novel tissue microarray (TMA) based analysis platform was developed. TMAs were constructed containing 8 different tissue cylinders from 144 primary NSCLCs. From 62 of these patients additional nodal metastases were sampled. EGFR gene copy number and EGFR expression was analyzed by FISH and immunohistochemistry according to the suggested guidelines. 13 (9.0%) of the 144 evaluated tumors showed EGFR amplification and 37 (25.7%) tumors high polysomy in at least one tumor area. In 7 (53.8%) of 13 amplified cases the analysis of different tumor areas revealed subclones without EGFR gene copy gain next to subclones with amplification. All of the 36 evaluable tumors with high polysomy showed heterogeneity of EGFR gene copy number with areas negative for gene copy gain within the individual tumors. Heterogeneity of EGFR gene copy gain in lung cancer challenges the concept of using small biopsies for the analysis of EGFR FISH status. EGFR gene copy number is highly heterogeneous within individual NSCLCs and this finding might well be a reason for the controversial clinical data existing regarding responsiveness to anti-EGFR therapy.

EGFR mutation status in brain metastases of non-small cell lung carcinoma

Brain metastases are a frequent and grave complication of non-small cell lung carcinoma (NSCLC). The prognosis is generally poor, despite standard therapy based on surgery and radiotherapy. A degree of understanding of the molecular basis of tumors has led to the development of targeted agents with promising initial findings for the treatment of NSCLC. EGFR mutations have been identified which are associated with significant sensitivity to EGFR tyrosine kinase inhibitors (TKI) and correlate with improved outcome in patients with NSCLC who are treated with these agents. The adoption of treatment tailored to the genetic make-up of individual tumors could lead to substantial therapeutic improvements, and such targeted therapy might be considered as a therapeutic option for brain metastases in the future. We review current knowledge about EGFR mutation status in the specific context of brain metastasis: its association with the response of brain metastases to TKI, its prevalence in brain metastases, and the correlation between mutation status in metastases as compared to the corresponding primary lung carcinoma.

Discrepancies between primary tumor and metastasis: a literature review on clinically established biomarkers

The identification of predictive factors of response is critical for the development and appropriate use of anti-cancer agents. The evaluation of biomarkers is usually performed by analyzing the primary tumor tissues but this approach does not take into account potential discrepancies between primary tumor and secondary lesions. This review proposes to describe currently available data regarding differential expression of established biomarkers between primary tumor and matched metastasis. In light of recent data, the need of iterative biopsies in metastatic setting has been suggested but technical and methodological limits in such analyses should not be ignored and this strategy cannot be definitively validated. Complementary studies are still needed since the question of spatial and temporal variability of biomarkers in solid tumors is clearly a key issue in an era where personalized therapy is strongly advocated by clinicians, researchers and patients.