Targeted Therapy for Brain Metastases: Improving the Therapeutic Ratio

Targeting autophagy: a promising approach for the treatment of breast cancer brain metastases

Patients with breast tumors that metastasize to the brain have limited treatment options and a very poor prognosis. More effective therapeutic strategies are desperately needed for this patient population. Recent evidence demonstrates that brain metastases arising from breast tumors display altered energy production that results in enhanced autophagy. Preclinical studies have shown that genetically or pharmacologically disrupting the autophagy pathway significantly decreases the brain metastatic burden, resulting in improved animal survival and increased sensitivity to lapatinib. These findings pave the way for the development of novel strategies targeting autophagy for breast cancer patients with brain metastatic disease.

PMS2 amplification contributes brain metastasis from lung cancer

BACKGROUND

Lung adenocarcinoma metastasizing to the brain results in a notable increase in patient mortality. The high incidence and its impact on survival presents a critical unmet need to develop an improved understanding of its mechanisms.

METHODS

To identify genes that drive brain metastasis of tumor cells, we collected cerebrospinal fluid samples and paired plasma samples from 114 lung adenocarcinoma patients with brain metastasis and performed 168 panel-targeted gene sequencing. We examined the biological behavior of PMS2 (PMS1 Homolog 2)-amplified lung cancer cell lines through wound healing assays and migration assays. In vivo imaging techniques are used to detect fluorescent signals that colonize the mouse brain. RNA sequencing was used to compare differentially expressed genes between PMS2 amplification and wild-type lung cancer cell lines.

RESULTS

We discovered that PMS2 amplification was a plausible candidate driver of brain metastasis. Via in vivo and in vitro assays, we validated that PMS2 amplified PC-9 and LLC lung cancer cells had strong migration and invasion capabilities. The functional pathway of PMS2 amplification of lung cancer cells is mainly enriched in thiamine, butanoate, glutathione metabolism.

CONCLUSION

Tumor cells elevated expression of PMS2 possess the capacity to augment the metastatic potential of lung cancer and establish colonies within the brain through metabolism pathways.

Early therapy evaluation of intra-arterial trastuzumab injection in a human breast cancer xenograft model using multiparametric MR imaging

PURPOSE

To investigate the treatment efficacy of intra-arterial (IA) trastuzumab treatment using multiparametric magnetic resonance imaging (MRI) in a human breast cancer xenograft model.

MATERIALS AND METHODS

Human breast cancer cells (BT474) were stereotaxically injected into the brains of nude mice to obtain a xenograft model. The mice were divided into four groups and subjected to different treatments (IA treatment [IA-T], intravenous treatment [IV-T], IA saline injection [IA-S], and the sham control group). MRI was performed before and at 7 and 14 d after treatment to assess the efficacy of the treatment. The tumor volume, apparent diffusion coefficient (ADC), and dynamic contrast-enhanced (DCE) MRI parameters (Ktrans, Kep, Ve, and Vp) were measured.

RESULTS

Tumor volumes in the IA-T group at 14 d after treatment were significantly lower than those in the IV-T group (13.1 mm3 [interquartile range 8.48-16.05] vs. 25.69 mm3 [IQR 20.39-30.29], p = 0.005), control group (IA-S, 33.83 mm3 [IQR 32.00-36.30], p<0.01), and sham control (39.71 mm3 [IQR 26.60-48.26], p <0.001). The ADC value in the IA-T group was higher than that in the control groups (IA-T, 7.62 [IQR 7.23-8.20] vs. IA-S, 6.77 [IQR 6.48-6.87], p = 0.044 and vs. sham control, 6.89 [IQR 4.93-7.48], p = 0.004). Ktrans was significantly decreased following the treatment compared to that in the control groups (p = 0.002 and p<0.001 for vs. IA-S and sham control, respectively). Tumor growth was decreased in the IV-T group compared to that in the sham control group (25.69 mm3 [IQR 20.39-30.29] vs. 39.71 mm3 [IQR 26.60-48.26], p = 0.27); there was no significant change in the MRI parameters.

CONCLUSION

IA treatment with trastuzumab potentially affects the early response to treatment, including decreased tumor growth and decrease of Ktrans, in a preclinical brain tumor model.

High-Dose Ionizing Radiation Impairs Healthy Dendrite Growth in C. elegans

Purpose

The nervous system is vulnerable to radiation damage, and further optimization is required to increase the efficacy of radiation therapy while reducing harm to neurons. Given recent developments in heavy ion therapy, experimental models would be valuable to improve these therapies. We used the nematode Caenorhabditis elegans (C. elegans) to evaluate the effects of high-dose radiation on neuron development.

Methods and Materials

In this study, we used confocal microscopy to assess dendritic growth of the PVD nociceptor after high-dose gamma-irradiation from a Cs-137 source.

Results

Irradiation during an early larval stage (L2) delayed overall development but also independently impaired dendrite outgrowth in the PVD nociceptive neuron. Irradiation at L4 larval stage did not result in significant alterations in dendrite morphology.

Conclusions

The nematode C. elegans can serve as a high-throughput model to study the effects of high-dose radiation on dendrite growth. We propose that C. elegans can be useful for studies of experimental radiation therapy modalities and dose rates for translational research.

Clinical utility of cerebrospinal fluid-derived circular RNAs in lung adenocarcinoma patients with brain metastases

Background

Free circular RNAs(circRNAs) escaping from primary lesion of cancer to brain are strictly regulated by blood–brain barrier and therefore cerebrospinal fluid (CSF) circRNAs have potential advantage in exploring biomarkers and mechanism of brain metastasis in lung cancer.

Methods

We collected paired cerebrospinal fluid, plasma and tumor tissues from 21 lung adenocarcinoma (ADC) patients with brain metastases (BM) and performed RNA sequencing.

Results

Compared to tumor tissue and plasma, circRNAs in CSF were characterized by lower number of spieces but higher abundance. Notably, CSF-circRNAs displayed high heterogeneity among different BM lung ADC patients. A total of 60 CSF-circRNAs was identified and associated with shorten overall survival. The circRNA-miRNA-mRNA network analysis revealed that the 60 CSF-circRNAs involved in cancer-associated pathways, and five of them showed strong association with WNT signaling pathway. Validation by RT-PCR of CSF and in vitro experiments of the five candidate circRNAs support their potential roles in cell proliferation and invasion.

Conclusions

In summary, our results depicted the heterogenous CSF-circRNAs profiles among BM lung ADC and implied that CSF-circRNAs may be promising prognosis-related biomarkers.

Genomic comparison between cerebrospinal fluid and primary tumor revealed the genetic events associated with brain metastasis in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is most common pathological type of lung cancer. LUAD with brain metastases (BMs) usually have poor prognosis. To identify the potential genetic factors associated with BM, a genomic comparison for BM cerebrospinal fluid (CSF) and primary lung tumor samples obtained from 1082 early- and late-stage LUAD patients was performed. We found that single nucleotide variation (SNV) of EGFR was highly enriched in CSF (87% of samples). Compared with the other primary lung tissues, copy number gain of EGFR (27%), CDK4 (11%), PMS2 (11%), MET (10%), IL7R (8%), RICTOR (7%), FLT4 (5%), and FGFR4 (4%), and copy number loss of CDKN2A (28%) and CDKN2B (18%) were remarkably more frequent in CSF samples. CSF had significantly lower tumor mutation burden (TMB) level but more abundant copy number variant. It was also found that the relationships among co-occurrent and mutually exclusive genes were dynamically changing with LUAD development. Additionally, CSF (97% of samples) harbored more abundant targeted drugs related driver and fusion genes. The signature 15 associated with defective DNA mismatch repair (dMMR) was only identified in the CSF group. Cancer associated pathway analysis further revealed that ErbB (95%) and cell cycle (84%) were unique pathways in CSF samples. The tumor evolution analysis showed that CSF carried significantly fewer clusters, but subclonal proportion of EGFR was remarkably increased with tumor progression. Collectively, CSF sequencing showed unique genomic characteristics and the intense copy number instability associated with cell cycle disorder and dMMR might be the crucial genetic factors in BM of LUAD.

A common goal to CARE: Cancer Advocates, Researchers, and Clinicians Explore current treatments and clinical trials for breast cancer brain metastases

Breast cancer is the most commonly diagnosed cancer in women worldwide. Approximately one-tenth of all patients with advanced breast cancer develop brain metastases resulting in an overall survival rate of fewer than 2 years. The challenges lie in developing new approaches to treat, monitor, and prevent breast cancer brain metastasis (BCBM). This review will provide an overview of BCBM from the integrated perspective of clinicians, researchers, and patient advocates. We will summarize the current management of BCBM, including diagnosis, treatment, and monitoring. We will highlight ongoing translational research for BCBM, including clinical trials and improved detection methods that can become the mainstay for BCBM treatment if they demonstrate efficacy. We will discuss preclinical BCBM research that focuses on the intrinsic properties of breast cancer cells and the influence of the brain microenvironment. Finally, we will spotlight emerging studies and future research needs to improve survival outcomes and preserve the quality of life for patients with BCBM.

Impact of Low-Dose Computed Tomography Screening for Primary Lung Cancer on Subsequent Risk of Brain Metastasis

INTRODUCTION

Brain metastasis (BM) is one of the most common metastases from primary lung cancer (PLC). Recently, the National Lung Screening Trial revealed the efficacy of low-dose computed tomography (LDCT) screening on LC mortality reduction. Nevertheless, it remains unknown if early detection of PLC through LDCT may be potentially beneficial in reducing the risk of subsequent metastases. Our study aimed to investigate the impact of LDCT screening for PLC on the risk of developing BM after PLC diagnosis.

METHODS

We used the National Lung Screening Trial data to identify 1502 participants who were diagnosed with PLC in 2002 to 2009 and have follow-up data for BM. Cause-specific competing risk regression was applied to evaluate an association between BM risk and the mode of PLC detection-that is, LDCT screen-detected versus non-LDCT screen-detected. Subgroup analyses were conducted in patients with early stage PLC and those who underwent surgery for PLC.

RESULTS

Of 1502 participants, 41.4% had PLC detected through LDCT screening versus 58.6% detected through other methods, for example, chest radiograph or incidental detection. Patients whose PLC was detected with LDCT screening had a significantly lower 3-year incidence of BM (6.5%) versus those without (11.9%), with a cause-specific hazard ratio (HR) of 0.53 (p = 0.001), adjusting for age at PLC diagnosis, PLC stage, PLC histology, and smoking status. This significant reduction in BM risk among PLCs detected through LDCT screening persisted in subgroups of participants with early stage PLC (HR = 0.47, p = 0.002) and those who underwent surgery (HR = 0.37, p = 0.001).

CONCLUSIONS

Early detection of PLC using LDCT screening is associated with lower risk of BM after PLC diagnosis on the basis of a large population-based study.

The promise of DNA damage response inhibitors for the treatment of glioblastoma

Glioblastoma (GBM), the most aggressive primary brain tumor, has a dismal prognosis. Despite our growing knowledge of genomic and epigenomic alterations in GBM, standard therapies and outcomes have not changed significantly in the past two decades. There is therefore an urgent unmet need to develop novel therapies for GBM. The inter- and intratumoral heterogeneity of GBM, inadequate drug concentrations in the tumor owing to the blood-brain barrier, redundant signaling pathways contributing to resistance to conventional therapies, and an immunosuppressive tumor microenvironment, have all hindered the development of novel therapies for GBM. Given the high frequency of DNA damage pathway alterations in GBM, researchers have focused their efforts on pharmacologically targeting key enzymes, including poly(ADP-ribose) polymerase (PARP), DNA-dependent protein kinase, ataxia telangiectasia-mutated, and ataxia telangiectasia and Rad3-related. The mainstays of GBM treatment, ionizing radiation and alkylating chemotherapy, generate DNA damage that is repaired through the upregulation and activation of DNA damage response (DDR) enzymes. Therefore, the use of PARP and other DDR inhibitors to render GBM cells more vulnerable to conventional treatments is an area of intense investigation. In this review, we highlight the growing body of data behind DDR inhibitors in GBM, with a focus on putative predictive biomarkers of response. We also discuss the challenges involved in the successful development of DDR inhibitors for GBM, including the intracranial location and predicted overlapping toxicities of DDR agents with current standards of care, and propose promising strategies to overcome these hurdles.

Metastatic sites as predictors in advanced NSCLC treated with PD-1 inhibitors: a systematic review and meta-analysis

BACKGROUND

Programmed cell death protein 1 (PD-1) inhibitors are the first-line treatment for advanced non-small-cell lung cancer (NSCLC) patients. However, their efficacy in metastatic NSCLC patients remains controversial.

AIM OF THE STUDY

The aim of our study was to evaluate the prognosis of advanced metastatic NSCLC patients treated with PD-1 inhibitors, and discuss the predictive effect of metastatic site on the long-term outcome.

METHODS

The Embase, Ovid Medline, Cochrane Central Register of Controlled Trials, and PubMed databases were systematically screened up to February 10, 2020. Twenty-five eligible studies, involving 8,067 patients that assessed the impact of metastatic sites on survival outcome were incorporated in our study. Overall survival (OS) and progression-free survival (PFS) were described as hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

Among the advanced NSCLC patients, the median proportion of brain, liver, bone, and adrenal gland metastases were 21%, 17%, 35%, and 21%, respectively. Patients with metastases to the brain, liver, and bone had worse OS compared to patients without these metastases when treated with PD-1 inhibitors. Similarly, patients with metastasis to the brain and liver were more likely to progress when treated with PD-1 inhibitors. Besides, patients with multiple metastatic sites had worse PFS compared to patients with one metastatic site, while no significant difference was found in terms of OS.

CONCLUSIONS

Based on the findings of our systematic review and meta-analysis, metastatic sites were independent predictors of the survival outcome for advanced NSCLC patients treated with PD-1 inhibitors.

A comprehensive review in improving delivery of small-molecule chemotherapeutic agents overcoming the blood-brain/brain tumor barriers for glioblastoma treatment

Glioblastoma (GBM) is the most common and lethal primary brain tumor which is highly resistant to conventional radiotherapy and chemotherapy, and cannot be effectively controlled by surgical resection. Due to inevitable recurrence of GBM, it remains essentially incurable with a median overall survival of less than 18 months after diagnosis. A great challenge in current therapies lies in the abrogated delivery of most of the chemotherapeutic agents to the tumor location in the presence of blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB). These protective barriers serve as a selectively permeable hurdle reducing the efficacy of anti-tumor drugs in GBM therapy. This work systematically gives a comprehensive review on: (i) the characteristics of the BBB and the BBTB, (ii) the influence of BBB/BBTB on drug delivery and the screening strategy of small-molecule chemotherapeutic agents with promising BBB/BBTB-permeable potential, (iii) the strategies to overcome the BBB/BBTB as well as the techniques which can lead to transient BBB/BBTB opening or disruption allowing for improving BBB/BBTB-penetration of drugs. It is hoped that this review provide practical guidance for the future development of small BBB/BBTB-permeable agents against GBM as well as approaches enhancing drug delivery across the BBB/BBTB to GBM.

Effects of Radiation Therapy on Neural Stem Cells

Brain and nervous system cancers in children represent the second most common neoplasia after leukemia. Radiotherapy plays a significant role in cancer treatment; however, the use of such therapy is not without devastating side effects. The impact of radiation-induced damage to the brain is multifactorial, but the damage to neural stem cell populations seems to play a key role. The brain contains pools of regenerative neural stem cells that reside in specialized neurogenic niches and can generate new neurons. In this review, we describe the advances in radiotherapy techniques that protect neural stem cell compartments, and subsequently limit and prevent the occurrence and development of side effects. We also summarize the current knowledge about neural stem cells and the molecular mechanisms underlying changes in neural stem cell niches after brain radiotherapy. Strategies used to minimize radiation-related damages, as well as new challenges in the treatment of brain tumors are also discussed.

Developments in the Space of New MAPK Pathway Inhibitors for BRAF-Mutant Melanoma

The characterization of the MAPK signaling pathway has led to the development of multiple promising targeted therapy options for a subset of patients with metastatic melanoma. The combination of BRAF and MEK inhibitors represents an FDA-approved standard of care in patients with metastatic and resected BRAF-mutated melanoma. There are currently three FDA-approved BRAF/MEK inhibitor combinations for the treatment of patients with BRAF-mutated melanoma. Although there have been significant advances in the field of targeted therapy, further exploration of new targets within the MAPK pathway will strengthen therapeutic options for patients. Important clinical and translational research focuses on mechanisms of resistance, predictive biomarkers, and challenging patient populations such as those with brain metastases or resected melanoma.

Ultra-small but ultra-effective: Folic acid-targeted gold nanoclusters for enhancement of intracranial glioma tumors' radiation therapy efficacy

The aim of the present study is to investigate folic acid and BSA decorated gold nanoclusters (FA-AuNCs) effect on the enhancement of intracranial C6 glioma tumors radiation therapy (RT) efficacy. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements exhibited about 2.5 times more FA-AuNCs uptake by C6 cancer cells (32.8 ng/10⁶ cells) than the normal cells. FA-AuNCs had significantly higher concentration in the brain tumors (8.1 μg/mg) in comparison with surrounding normal brain tissue (4.3 μg/mg). Moreover, FA-AuNCs exhibited dose enhancement factor (DEF) of 1.6. The glioma-bearing rats' survival times were almost doubled at radiation therapy + FA-AuNCs (25.0 ± 1.5 days) in comparison with no-treatment group (12.8 ± 0.7 days). The Ki-67 labeling index was 48.89% ± 9.93 for control, 29.98% ± 8.32 for RT, and 11.53% ± 7.65 for RT + FA-AuNCs. Therefore, FA-AuNCs can be effective radiosensitizers for intracranial glioma tumors RT.

Non-small-cell Lung Cancer With Brain Metastasis at Presentation

BACKGROUND

Data on the prevalence of brain metastases at presentation in patients with non-small-cell lung cancer (NSCLC) are limited. We queried the National Cancer Data Base to determine prevalence, clinical risk factors, and outcomes of patients with NSCLC presenting with brain metastases.

PATIENTS AND METHODS

Patients with NSCLC diagnosed between 2010 and 2012 were identified using the National Cancer Data Base. The risk of brain metastases for individual variables was summarized by odds ratios and calculated using logistic regression analysis. The Kaplan-Meier product limit method was used to calculate the median and 1-, 2-, and 3-year overall survival (OS).

RESULTS

Brain metastases were observed in 47,546 (10.4%) of the 457,481 patients with NSCLC overall. The prevalence of brain metastases was much higher (26%) in patients with stage IV disease at presentation. On multivariate analysis, younger age, adenocarcinoma or large cell histology, tumor size > 3 cm, tumor grade ≥ II, and node-positive disease were associated with brain metastases. The prevalence of brain metastases ranged from as low as 0.57% in patients with only 1 risk factor to as high as 22% in patients with all 5 risk factors. The median and 1-, 2-, and 3-year OS for patients with brain metastases were 6 months and 29.9%, 14.3%, and 8.4%, respectively, with the 3-year OS increasing to 36.2% in those with T1/2 and N0/1 undergoing surgery for the primary site.

CONCLUSIONS

In patients with NSCLC, the risk of brain metastases at presentation may be calculated based on 5 clinical variables. Selected patients with brain metastases at presentation may achieve prolonged benefit.

Risk factors of brain metastasis during the course of EGFR-TKIs therapy for patients with EGFR-mutated advanced lung adenocarcinoma

Controversial value of prophylactic cranial irradiation (PCI) in NSCLC in terms of survival benefit prompted us to explore the possible risk factors for brain metastasis (BM) during the course of EGFR-TKIs therapy from EGFR-mutated advanced lung adenocarcinoma and identify the potential population most likely to benefit from PCI, because BM remains a therapeutically challenging issue. We retrospectively reviewed the records of 134 patients with EGFR-mutated advanced lung adenocarcinoma between 2008 and 2012. The cumulative incidence of BM was calculated by the Kaplan-Meier method, and Multivariate Cox regression analysis was used to assess the independent risk factors for BM. Thirty-four patients (34/134, 25.4%) developed BM during the course of EGFR-TKIs therapy. Moreover, the Multivariate analysis indicated that age ≤ 53 years (HR: 2.751, 95 % CI: 1.326-5.707; p = 0.007), serum carcinoembryonic antigen (CEA) ≥ 23 ng/mL (HR: 3.197, 95 % CI: 1.512-6.758; p = 0.002) and EGFR exon 21 point mutations (HR: 2.769, 95 % CI: 1.355-5.659; p= 0.005) were the independent high-risk factors for developing BM, which could offer important insights into the individualized treatment. Further studies are warranted to validate our findings.

Medical management of brain metastases and leptomeningeal disease in patients with breast carcinoma

Breast cancer is the most common malignancy among women and accounts for the second highest number of cancer-related deaths. With patients surviving longer due to advances in systemic control, the incidence of CNS involvement is increasing; however, the management of CNS metastases has not undergone parallel advancements. The blood–brain barrier limits the efficacy of most systemic chemotherapies, and the utilization of surgery and radiation beyond first-line therapy is limited. We will explore the recent developments in the medical management of breast cancer brain metastasis. Beyond traditional chemotherapy, we will also discuss targeted therapies and immunotherapies which may provide a survival benefit to this population and thus, offer further treatment options and a path for future research and treatment advances.

Brain Metastases at Presentation in Patients With Non-Small Cell Lung Cancer

OBJECTIVE

We used brain radiotherapy as a surrogate for the presence of brain metastases in patients with non-small cell lung cancer (NSCLC) to determine the prevalence of brain metastases using the Surveillance Epidemiology and End Results database.

METHODS

Patients with NSCLC diagnosed between 1988 and 1997 were subdivided according to brain radiotherapy status at presentation into: "none" or "radiation therapy indicated." We calculated the frequency of brain radiotherapy use in all patients. Odds ratios (ORs) for the indication of brain radiotherapy were calculated for individual prespecified covariates of interest. All statistical tests were 2-sided and P<0.05 were considered significant.

RESULTS

At presentation, brain radiotherapy was indicated in 10,963 (8.3%) of the 131,456 patients diagnosed with NSCLC between 1988 and 1997. On multivariable analysis the following were significantly associated with brain radiotherapy use: age (OR, 0.653 per 10 y increase in age; 95% confidence interval [CI]: 0.642, 0.665); female sex (OR, 1.05; 95% CI: 1.01, 1.10]); adenocarcinoma histology (HR, 1.67; 95% CI: 1.58, 1.76) or large cell or other histology (OR, 1.67; 95% CI: 1.57, 1.77); tumor size>3 cm (3.1 to 5 cm OR, 1.22; 95% CI: 1.14, 1.30 and >5 cm OR, 1.25; 95% CI: 1.17, 1.33); tumor grade >II (grade III OR, 1.82; 95% CI: 1.69, 1.95 and grade IV OR, 1.91; 95% CI: 1.73, 2.11); and nodal involvement N1 (OR, 1.33; 95% CI: 1.20, 1.47), N2 (OR, 2.24; 95% CI: 2.10, 2.40), and N3 (OR, 2.39; 95% CI: 2.19, 2.60).

CONCLUSIONS

Brain radiotherapy is indicated in over 8% of patients with NSCLC at presentation. We demonstrated that the risk of brain metastasis at presentation may be stratified with the use of 6 clinical factors.

Trastuzumab uptake and its relation to efficacy in an animal model of HER2-positive breast cancer brain metastasis

Purpose

The extent to which efficacy of the HER2 antibody Trastuzumab in brain metastases is limited by access of antibody to brain lesions remains a question of significant clinical importance. We investigated the uptake and distribution of trastuzumab in brain and mammary fat pad grafts of HER2-positive breast cancer to evaluate the relationship of these parameters to the anti-tumor activity of trastuzumab and trastuzumab emtansine (T-DM1).

Methods

Mouse transgenic breast tumor cells expressing human HER2 (Fo2-1282 or Fo5) were used to establish intracranial and orthotopic tumors. Tumor uptake and tissue distribution of systemically administered ⁸⁹Zr-trastuzumab or muMAb 4D5 (murine parent of trastuzumab) were measured by PET and ELISA. Efficacy of muMAb 4D5, the PI3K/mTOR inhibitor GNE-317, and T-DM1 was also assessed.

Results

⁸⁹Zr-trastuzumab and muMAb 4D5 exhibited robust uptake into Fo2-1282 brain tumors, but not normal brains. Uptake into brain grafts was similar to mammary grafts. Despite this, muMAb 4D5 was less efficacious in brain grafts. Co-administration of muMAb 4D5 and GNE-317, a brain-penetrant PI3K/mTOR inhibitor, provided longer survival in mice with brain lesions than either agent alone. Moreover, T-DM1 increased survival in the Fo5 brain metastasis model.

Conclusions

In models of HER2-positive breast cancer brain metastasis, trastuzumab efficacy does not appear to be limited by access to intracranial tumors. Anti-tumor activity improved with the addition of a brain-penetrant PI3K/mTOR inhibitor, suggesting that combining targeted therapies is a more effective strategy for treating HER2-positive breast cancer brain metastases. Survival was also extended in mice with Fo5 brain lesions treated with T-DM1.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4279-4) contains supplementary material, which is available to authorized users.

Perillyl Alcohol and Its Drug-Conjugated Derivatives as Potential Novel Methods of Treating Brain Metastases

Metastasis to the central nervous system remains difficult to treat, and such patients are faced with a dismal prognosis. The blood-brain barrier (BBB), despite being partially compromised within malignant lesions in the brain, still retains much of its barrier function and prevents most chemotherapeutic agents from effectively reaching the tumor cells. Here, we review some of the recent developments aimed at overcoming this obstacle in order to more effectively deliver chemotherapeutic agents to the intracranial tumor site. These advances include intranasal delivery to achieve direct nose-to-brain transport of anticancer agents and covalent modification of existing drugs to support enhanced penetration of the BBB. In both of these areas, use of the natural product perillyl alcohol, a monoterpene with anticancer properties, contributed to promising new results, which will be discussed here.

[Immunohistochemical hormonal mismatch and human epidermal growth factor type 2 [HER2] phenotype of brain metastases in breast cancer carcinoma compared to primary tumors]

INTRODUCTION

Phenotype changes between primary tumor and the corresponding brain metastases are recent reported data. Breast cancer, with biological markers predicting prognosis and guiding therapeutic strategy remains an interesting model to observe and evaluate theses changes. The objective of our study was to compare molecular features (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor type 2, [HER2]) between brain metastases and its primary tumor in patients presenting with pathologically confirmed breast cancer.

MATERIAL AND METHODS

This retrospective study was based on the immunohistochemical analysis of the brain metastases paraffin embedded samples stored in our institutional tumor bank, after surgical resection. The level of expression of hormonal receptors and HER2 on brain metastases were centrally reviewed and compared to the expression status in primary breast cancer from medical records.

RESULTS

Forty-four samples of brain metastases were available for analysis. Hormonal receptor modification status was observed in 11/44 brain metastases (25%) for ER and 6/44 (13.6%) for PR. A modification of HER2 overexpression was observed in brain metastases in 6/44 (13.6%). Molecular subtype modification was shown in 17 cases (38.6%). A significant difference was demonstrated between time to develop brain metastases in cases without status modification (HER2, ER and PR) (med=49.5months [7.8-236.4]) and in cases in which brain metastases status differs from primary tumor (med=27.5months [0-197.3]), (P=0.0244, IC95=3.09-51.62, Mann and Whitney test).

CONCLUSION

the main interest of this study was to focus on the molecular feature changes between primary tumor and their brain metastases. Time to develop brain metastases was correlated to phenotypic changes in brain metastases.

Safety and efficacy of carmustine (BCNU) wafers for metastatic brain tumors

BACKGROUND

Carmustine (BCNU) wafers (Gliadel) prolongs local disease control and progression-free survival (PFS) in patients with malignant gliomas. However, in metastatic brain tumors, there is a paucity of evidence in support of its safety and efficacy. The goal of this study was to assess the safety and efficacy of Gliadel wafers in patients with metastatic brain tumors.

METHODS

We retrospectively reviewed the University of Washington experience with Gliadel wafers for metastatic brain tumors between 2000 and 2015.

RESULTS

Gliadel wafers were used in 14 patients with metastatic brain tumors during the period reviewed. There were no postoperative seizures, strokes, or hemorrhages. There was one postoperative wound infection necessitating return to the operating room. The mean time to tumor progression (n = 7) and death (n = 5) after Gliadel wafer implantation was 2.5 and 2.9 years, respectively. Age was the only variable affecting PFS in patients receiving Gliadel wafers. Patients <53 years old (n = 7) had a PFS of 0.52 years, whereas patients >53 years old (n = 7) had a PFS of 4.29 years (P = 0.02). There was no significant difference in PFS in relation to presenting Karnofsky Performance Status (P = 0.26), number of brain metastasis (P = 0.82), tumor volume (P = 0.54), prior surgery (P = 0.57), or prior radiation (P = 0.41). There were no significant differences in the mean survival in relationship to any variable including age.

CONCLUSIONS

BCNU wafers are a safe and a potentially efficacious adjunct to surgery and radiation for improving local disease control in metastatic brain tumors. Larger studies, however, are needed to examine overall efficacy and tumor specific efficacy.

Static magnetic field controls cell cycle in cultured human glioblastoma cells

Magnetic field has been widely used in clinical diagnostics or for clinical treatment and is an important biomedical technology. Glioblastoma multiforme U87 and U251 are models of a fast growing malignant cancer. We focused on cellular level drafting of these cell lines as a time-dependent effect indicator of static magnetic fields (2000 ± 600 Gauss) by using their fast-growing properties. Cell viability showed a significant decrease (p < 0.01). The results coincided with the occurrence of apoptotic signals or protein expression of cyclin B1 and cyclin dependent kinase 1 in a non-apoptotic manner. Cdk1 was decreased in proportion to ankyrin G and cyclin B1 (Chi-square test, p = 0.0366). Our findings suggest that static magnetic stimulation creates a specific cyto-proliferative pattern, rather than producing randomized growth impairment.

Phenyl group participation in rearrangements during collision-induced dissociation of deprotonated phenoxyacetic acid

RATIONALE

The identification of trace constituents in biological and environmental samples is frequently based on the fragmentation patterns resulting from the collision-induced dissociation (CID) of gas-phase ions. Credible mechanistic characterization of fragmentation processes, including rearrangements, is required to make reliable assignments for structures of precursor and product ions.

METHODS

Mass spectra were collected using both ion trap and triple quadrupole mass spectrometers operating in the negative ion mode. Precursor ion scans and CID of ions generated in-source were used to establish precursor-product ion relationships. Density functional theory (DFT) computations were performed at the MP2/6-311++G(2d,p)//B3LYP/6-31++G(2d,p) level of theory.

RESULTS

Product ions at m/z 93 and 107 obtained upon CID of phenoxyacetate were attributed to phenoxide and o-methylphenoxide, respectively. An isotopic labeling experiment and computations showed that the phenoxide ion was formed by intramolecular displacement with formation of an α-lactone and also by a Smiles rearrangement. Rearrangement of phenoxyacetate via the ion-neutral complex formed in the α-lactone displacement pathway gave the isomeric o-hydroxyphenylacetate ion which yielded o-methylphenoxide upon decarboxylation. Computations provided feasible energetics for these pathways.

CONCLUSIONS

Previously unrecognized and energetically favorable rearrangements during the collision-induced fragmentation of phenoxyacetate have been characterized using isotopic labeling and DFT computations. Notably, the phenyl substituent plays an indispensable role in each rearrangement process resulting in multiple pathways for the fragmentation of phenoxyacetate.

Therapeutic strategies to improve drug delivery across the blood-brain barrier

Resection of brain tumors is followed by chemotherapy and radiation to ablate remaining malignant cell populations. Targeting these populations stands to reduce tumor recurrence and offer the promise of more complete therapy. Thus, improving access to the tumor, while leaving normal brain tissue unscathed, is a critical pursuit. A central challenge in this endeavor lies in the limited delivery of therapeutics to the tumor itself. The blood-brain barrier (BBB) is responsible for much of this difficulty but also provides an essential separation from systemic circulation. Due to the BBB's physical and chemical constraints, many current therapies, from cytotoxic drugs to antibody-based proteins, cannot gain access to the tumor. This review describes the characteristics of the BBB and associated changes wrought by the presence of a tumor. Current strategies for enhancing the delivery of therapies across the BBB to the tumor will be discussed, with a distinction made between strategies that seek to disrupt the BBB and those that aim to circumvent it.

Rhubarb extract has a protective role against radiation-induced brain injury and neuronal cell apoptosis

Oxidative stress caused by ionizing radiation is involved in neuronal damage in a number of disorders, including trauma, stroke, Alzheimer's disease and amyotrophic lateral sclerosis. Ionizing radiation can lead to the formation of free radicals, which cause neuronal apoptosis and have important roles in the development of some types of chronic brain disease. The present study evaluated the effects of varying concentrations (2, 5 and 10 µg/ml) of ethanolic rhubarb extract on the neuronal damage caused by irradiation in primary neuronal cultures obtained from the cortices of rat embryos aged 20 days. Brain damage was induced with a single dose of γ-irradiation that induced DNA fragmentation, increased lactate dehydrogenase release in neuronal cells and acted as a trigger for microglial cell proliferation. Treatment with rhubarb extract significantly decreased radiation-induced lactate dehydrogenase release and DNA fragmentation, which are important in the process of cell apoptosis. The rhubarb extract exhibited dose-dependent inhibition of lactate dehydrogenase release and neuronal cell apoptosis that were induced by the administration of ionizing radiation. The effect of a 10 µg/ml dose of rhubarb extract on the generation of reactive oxygen species (ROS) induced by radiation was also investigated. This dose led to significant inhibition of ROS generation. In conclusion, the present study showed a protective role of rhubarb extract against irradiation-induced apoptotic neuronal cell death and ROS generation.

MicroRNA-200 family members and ZEB2 are associated with brain metastasis in gastric adenocarcinoma

Although the incidence of brain metastasis in gastric cancer is relatively low, its prevalence may increase with improved therapy and longer survival tumors. The molecular mechanisms underlying brain metastases are not well understood. To gain insight into the mechanism of brain metastasis, we studied differences in microRNA (miRNA) expression levels in 8 cases of matched primary gastric adenocarcinoma and brain metastatic adenocarcinoma using the Illumina microRNA microarray chip. We identified 6 upregulated and 2 downregulated miRNAs in all 8 cases simultaneously. Interestingly, 2 out of 8 miRNAs (hsa-miR‑141-3p and hsa-miR-200b-3p) belonged to the miR-200 family. Online microRNA database searching revealed that ZEB2 is the top-ranked target gene for hsa-miR141-3p and hsa-miR-200b-3p, prompting us to focus ZEB2 expression in brain metastatic adenocarcinoma. We confirmed that ZEB2 expression was markedly downregulated in some brain metastatic samples. In addition, decreased ZEB2 expression was noted by western blot analysis of 2 metastatic gastric adenocarcinoma cell types that were derived by in vivo selection following intracardiac injection of gastric cancer cell lines. In conclusion, we demonstrate that expression of miRNA-200 family members and ZEB2 are associated with brain metastases of gastric adenocarcinoma, not only in matched patient samples, but also in metastatic cell lines that were derived by in vivo selection.

Angiotensin-(1-7) prevents radiation-induced inflammation in rat primary astrocytes through regulation of MAP kinase signaling

About 500,000 new cancer patients will develop brain metastases in 2013. The primary treatment modality for these patients is partial or whole brain irradiation which leads to a progressive, irreversible cognitive impairment. Although the exact mechanisms behind this radiation-induced brain injury are unknown, neuroinflammation in glial populations is hypothesized to play a role. Blockers of the renin-angiotensin system (RAS) prevent radiation-induced cognitive impairment and modulate radiation-induced neuroinflammation. Recent studies suggest that RAS blockers may reduce inflammation by increasing endogenous concentrations of the anti-inflammatory heptapeptide angiotensin-(1-7) [Ang-(1-7)]. Ang-(1-7) binds to the AT(1-7) receptor and inhibits MAP kinase activity to prevent inflammation. This study describes the inflammatory response to radiation in astrocytes characterized by radiation-induced increases in (i) IL-1β and IL-6 gene expression; (ii) COX-2 and GFAP immunoreactivity; (iii) activation of AP-1 and NF-κB transcription factors; and (iv) PKCα, MEK, and ERK (MAP kinase) activation. Treatment with U-0126, a MEK inhibitor, demonstrates that this radiation-induced inflammation in astrocytes is mediated through the MAP kinase pathway. Ang-(1-7) inhibits radiation-induced inflammation, increases in PKCα, and MAP kinase pathway activation (phosphorylation of MEK and ERK). Additionally Ang-(1-7) treatment leads to an increase in dual specificity phosphatase 1 (DUSP1). Furthermore, treatment with sodium vanadate (Na3VO4), a phosphatase inhibitor, blocks Ang-(1-7) inhibition of radiation-induced inflammation and MAP kinase activation, suggesting that Ang-(1-7) alters phosphatase activity to inhibit radiation-induced inflammation. These data suggest that RAS blockers inhibit radiation-induced inflammation and prevent radiation-induced cognitive impairment not only by reducing Ang II but also by increasing Ang-(1-7) levels.

TGF-β-induced miR10a/b expression promotes human glioma cell migration by targeting PTEN

Human gliomas are associated with high rates of morbidity and mortality. In the brain, increased mRNA levels of transforming growth factor β (TGF-β) correlate with the degree of malignancy of human gliomas. miR10a/10b expression has been demonstrated to be associated with TGF-β expression in brain tumors, and it is reported that TGF-β induces miR10 expression. Therefore, miR10a/10b expression may be induced by TGF-β expression and may be involved in the TGF-β-induced migration of brain tumor cells. The present study examined the expression of TGF-β and miR10a/10b in the tissues of 10 patients with brain tumors using quantitative PCR (qPCR), and the correlation between TGF-β and miR10a or miR10b expression was analyzed. Additionally, U251 and SHG-44 cells were treated with TGF-β and the expression of miR10a/10b was examined. Further, cell migration was analyzed following transfection of U251 cells with miR10a/10b and the association between miR10a/10b and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was investigated. U251 cells were transfected with miR10a/10b inhibitors and a PTEN expression plasmid prior to TGF-β treatment and then cell migration was assessed. A significant correlation was identified between TGF-β and miR10a expression (r2=0.6936, P=0.007) and between TGF-β and miR10b expression (r2=0.5876, P=0.02) in the tissues of patients with brain tumors. The results also showed that TGF-β induces miR10a/10b expression and that TGF-β-induced miR10a/10b expression promotes cell migration through the suppression of PTEN. In conclusion, TGF-β-induced miR10a/10b promotes brain tumor migration. This study may provide a number of suggestions for the clinical treatment of brain tumors.

Enhancing the efficacy of drug-loaded nanocarriers against brain tumors by targeted radiation therapy

Glioblastoma multiforme (GBM) is a common, usually lethal disease with a median survival of only ~15 months. It has proven resistant in clinical trials to chemotherapeutic agents such as paclitaxel that are highly effective in vitro, presumably because of impaired drug delivery across the tumor's blood-brain barrier (BBB). In an effort to increase paclitaxel delivery across the tumor BBB, we linked the drug to a novel filomicelle nanocarrier made with biodegradable poly(ethylene-glycol)-block-poly(ε-caprolactone-r-D,L-lactide) and used precisely collimated radiation therapy (RT) to disrupt the tumor BBB's permeability in an orthotopic mouse model of GBM. Using a non-invasive bioluminescent imaging technique to assess tumor burden and response to therapy in our model, we demonstrated that the drug-loaded nanocarrier (DLN) alone was ineffective against stereotactically implanted intracranial tumors yet was highly effective against GBM cells in culture and in tumors implanted into the flanks of mice. When targeted cranial RT was used to modulate the tumor BBB, the paclitaxel-loaded nanocarriers became effective against the intracranial tumors. Focused cranial RT improved DLN delivery into the intracranial tumors, significantly improving therapeutic outcomes. Tumor growth was delayed or halted, and survival was extended by &gt;50% (p<0.05) compared to the results obtained with either RT or the DLN alone. Combinations of RT and chemotherapeutic agents linked to nanocarriers would appear to be an area for future investigations that could enhance outcomes in the treatment of human GBM.

Targeted delivery of antibody-based therapeutic and imaging agents to CNS tumors: crossing the blood-brain barrier divide

INTRODUCTION

Brain tumors are inherently difficult to treat in large part due to the cellular blood-brain barriers (BBBs) that limit the delivery of therapeutics to the tumor tissue from the systemic circulation. Virtually no large molecules, including antibody-based proteins, can penetrate the BBB. With antibodies fast becoming attractive ligands for highly specific molecular targeting to tumor antigens, a variety of methods are being investigated to enhance the access of these agents to intracranial tumors for imaging or therapeutic applications.

AREAS COVERED

This review describes the characteristics of the BBB and the vasculature in brain tumors, described as the blood-brain tumor barrier (BBTB). Antibodies targeted to molecular markers of central nervous system (CNS) tumors will be highlighted, and current strategies for enhancing the delivery of antibodies across these cellular barriers into the brain parenchyma to the tumor will be discussed. Noninvasive imaging approaches to assess BBB/BBTB permeability and/or antibody targeting will be presented as a means of guiding the optimal delivery of targeted agents to brain tumors.

EXPERT OPINION

Preclinical and clinical studies highlight the potential of several approaches in increasing brain tumor delivery across the BBB divide. However, each carries its own risks and challenges. There is tremendous potential in using neuroimaging strategies to assist in understanding and defining the challenges to translating and optimizing molecularly targeted antibody delivery to CNS tumors to improve clinical outcomes.

Progress in the biological understanding and management of breast cancer-associated central nervous system metastases

Metastasis to the central nervous system (CNS) is a devastating neurological complication of systemic cancer. Brain metastases from breast cancer have been documented to occur in approximately 10%-16% of cases over the natural course of the disease with leptomeningeal metastases occurring in approximately 2%-5% of cases of breast cancer. CNS metastases among women with breast cancer tend to occur among those who are younger, have larger tumors, and have a more aggressive histological subtype such as the triple negative and HER2-positive subtypes. Treatment of CNS metastases involves various combinations of whole brain radiation therapy, surgery, stereotactic radiosurgery, and chemotherapy. We will discuss the progress made in the treatment and prevention of breast cancer-associated CNS metastases and will delve into the biological underpinnings of CNS metastases including evaluating the role of breast tumor subtype on the incidence, natural history, prognostic outcome, and impact of therapeutic efficacy.

Development and validation of sensitive liquid chromatography/tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue

A liquid chromatography-tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue was developed and fully validated. Methanol was used to precipitate proteins in brain tissue. Bendamustine and internal standard (chlorambucil) were separated with reverse-phase chromatography on a C-18 column with a gradient of water and 95% methanol in 0.1% formic acid. Positive mode electrospray ionization was applied with selected reaction monitoring to achieve 5 ng/ml lower limits of quantitation in mouse brain tissue. The calibration curve for bendamustine in mouse brain was linear between 5 and 2000 ng/ml. The within- and between-batch accuracy and precision of the assay were within 15% at 10, 100 and 1000 ng/ml. The recovery and matrix effect of bendamustine in mouse brain tissue ranged from 41.1% to 51.6% and 107.4% to 110.3%, respectively. The validated method was then applied to quantitate bendamustine in an animal study. Results indicate the assay can be applied to evaluate bendamustine disposition in mouse brain tissue. This assay will be applied in the future to detect and quantify bendamustine in human brain tissue samples.

TPI-287, a new taxane family member, reduces the brain metastatic colonization of breast cancer cells

Brain metastases of breast and other cancers remain resistant to chemotherapeutic regimens that are effective systemically, in part due to the blood-brain barrier. We report that TPI-287, a new microtubule-stabilizing agent, displays in vitro cytotoxic activity similar to taxanes and epothilones. Unlike the taxanes, TPI-287 is permeable through the blood-brain barrier. Brain-to-plasma ratios of TPI-287 after a single injection typically exceeded one and were as high as 63.8 in the rat and 14.1 in the mouse. A brain-tropic derivative of the MDA-MB-231 triple-negative breast cancer cell line, 231-BR, was used to test whether TPI-287 may be efficacious at preventing or treating brain metastases. TPI-287 had growth inhibitory effects comparable with paclitaxel when 231-BR tumor cells were injected into the mammary fat pad. Brain metastatic colonization was determined by intracardiac injection of 231-BR cells, with treatment beginning on day 3 to 4 postinjection, culminating in a histologic count of brain metastases in brains necropsied days 25 to 28 postinjection. In this assay, paclitaxel, ixabepilone, and nab paclitaxel did not have significant inhibitory activity. TPI-287 was ineffective in the same assay using a 6 mg/kg every week schedule; however an 18 mg/kg dose delivered on days 3, 7, and 11 significantly reduced the outgrowth of brain metastases (55% reduction, P = 0.028) and reduced proliferation in brain metastases (16% reduction, P = 0.008). When TPI-287 treatment was delayed until days 18, 22, and 26 postinjection, efficacy was reduced (17% reduction, not significant). These data suggest that TPI-287 may have efficacy when administered early in the course of the disease.

Therapeutic approaches for HER2-positive brain metastases: circumventing the blood-brain barrier

We aim to summarize data from studies of trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and brain metastasis and to describe novel methods being developed to circumvent the blood-brain barrier (BBB). A literature search was conducted to obtain data on the clinical efficacy of trastuzumab and lapatinib in patients with HER2-positive MBC and brain metastasis, as well as the transport of therapeutic molecules across the BBB. Trastuzumab-based therapy is the standard of care for patients with HER2-positive MBC. Post hoc and retrospective analyses show that trastuzumab significantly prolongs overall survival when given after the diagnosis of central nervous system (CNS) metastasis; this is probably attributable to its control of extracranial disease, although trastuzumab may have a direct effect on CNS disease in patients with local or general perturbation of the BBB. In patients without a compromised BBB, trastuzumab is thought to have limited access to the brain, because of its relatively large molecular size. Several approaches are being developed to enhance the delivery of therapeutic agents to the brain. These include physical or pharmacologic disruption of the BBB, direct intracerebral drug delivery, drug manipulation, and coupling drugs to transport vectors. Available data suggest that trastuzumab extends survival in patients with HER2-positive MBC and brain metastasis. Novel methods for delivery of therapeutic agents into the brain could be used in the future to enhance access to the CNS by trastuzumab, thereby improving its efficacy in this setting.

Involvement of epidermal growth factor receptor overexpression in the promotion of breast cancer brain metastasis

BACKGROUND

Brain-metastatic breast cancer (BMBC) is increasing and poses a severe clinical problem because of the lack of effective treatments and because the underlying molecular mechanisms are largely unknown. Recent work has demonstrated that deregulation of epidermal growth factor receptor (EGFR) may correlate with BMBC progression. However, the exact contribution that EGFR makes to BMBC remains unclear.

METHODS

The role of EGFR in BMBC was explored by serial analyses in a brain-trophic clone of human MDA-MB-231 breast carcinoma cells (231-BR cells). EGFR expression was inhibited by stable short-hairpin RNA transfection or by the kinase inhibitor erlotinib, and it was activated by heparin-binding epidermal growth factor-like growth factor (HB-EGF). Cell growth and invasion activities also were analyzed in vitro and in vivo.

RESULTS

EGFR inhibition or activation strongly affected 231-BR cell migration/invasion activities as assessed by an adhesion assay, a wound-healing assay, a Boyden chamber invasion assay, and cytoskeleton staining. Also, EGFR inhibition significantly decreased brain metastases of 231-BR cells in vivo. Surprisingly, changes to EGFR expression affected cell proliferation activities less significantly as determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, an anchorage-independent growth assay, and cell cycle analysis. Immunoblot analysis suggested that EGFR drives cells' invasiveness capability mainly through phosphoinositide 3-kinase/protein kinase B and phospholipase C γ downstream pathways. In addition, EGFR was involved less in proliferation because of the insensitivity of the downstream mitogen-activated protein kinase pathway.

CONCLUSIONS

The current results indicated that EGFR plays more important roles in cell migration and invasion to the brain than in cell proliferation progression on 231-BR cells, providing new evidence of the potential value of EGFR inhibition in treating BMBC.

Burden of breast cancer with brain metastasis: a French national hospital database analysis

OBJECTIVE

Incidence of breast cancer with brain metastases (BCBM) is increasing, especially among patients over-expressing HER2. Epidemiology on this sub-type of cancer is scarce, since cancer registries carry no information on the HER2 status. A retrospective database analysis was conducted to estimate the burden of BCBM, especially among HER2-positive patients in a secondary objective.

METHODS

Patients with a new diagnosis of BCBM carried out between January and December 2008 were identified from the national hospital database using the International Disease Classification. Patients receiving a targeted anti-HER2 therapy were identified from the national pharmacy database. Hospital and pharmacy claims were linked to estimate the burden of HER2-positive patients. Data on hospitalizations were extracted to describe treatment patterns and healthcare costs during a 1-year follow-up. Predictors of treatment cost were analyzed through multi-linear regression analysis.

RESULTS

Two thousand and ninety-nine BCBM patients were identified (mean age (SD) = 57.8 (13.6)), of whom 12.2% received a targeted anti-HER2 therapy; 79% of patients had brain metastases associated with extracranial metastases, and the attrition rate reached 82%. Patients received mostly palliative care (47.4%), general medical care (40.6%), and chemotherapy (35.0%). The total annual hospital cost of treatment was 8,426,392€, representing a mean cost of 22,591€ (±14,726) per patient, mainly influenced by extracranial metastases, surgical acts, and HER2-overexpression (p < 0.0001).

CONCLUSIONS

The database linkage of hospital and pharmacy claims is a relevant approach to identify sub-type of cancer. Chemotherapy was widely used as a systemic treatment for breast cancer rather than for local treatment of brain metastases whose morbi-mortality remains high. The variability of treatment costs suggests clinical heterogeneity and, thus, extensive individualization of protocols.

Expression of antigen processing and presenting molecules in brain metastasis of breast cancer

Defects in human leukocyte antigen class I antigen processing machinery (APM) component expression can have a negative impact on the clinical course of tumors and the response to T cell-based immunotherapy. Since brain metastases of breast cancer are of increasing clinical significance, the APM component expression levels and CD8(+) T cell infiltration patterns were analyzed in primary breast and metastatic brain lesions of breast cancer by immunohistochemistry. Comparison of unpaired 50 primary and 33 brain metastases showed lower expression of β2-microglobulin, transporter associated with antigen processing (TAP) 1, TAP2 and calnexin in the brain lesions. Although no significant differences were found in APM component scores between primary breast and brain lesions in 15 paired cases, primary breast lesions of which patients eventually developed brain metastases showed lower levels of β2-microglobulin, TAP1 and calnexin compared with breast lesions without known brain metastases. The extent of CD8(+) T cell infiltration was significantly higher in the lesions without metastasis compared with the ones with brain metastases, and was positively associated with the expression of TAP1 and calnexin. Furthermore, mouse tumor cells stably transfected with silencing hairpin (sh)RNA for TAP1 demonstrated a decreased susceptibility to cytotoxic T lymphocytes in vitro and enhanced spontaneous brain metastasis in vivo. These data support the functional significance of TAP1 expression in tumor cells. Taken together, our data suggest that patients with low or defective TAP1 or calnexin in primary breast cancers may be at higher risks for developing brain metastasis due to the defects in T cell-based immunosurveillance.

A review of current management of brain metastases

BACKGROUND

The brain metastasis (BM) represents one of the most common and refractory malignancies worldwide with a rising incidence in all countries. It is generally believed that once a BM has developed, this disease cannot be cured and has a poor prognosis. The challenges of managing this tumor include diagnosis and selective treatment options. In addition, patients with BM frequently have greater expectations of the current therapy outcomes, which hope to get long-term survival and good quality of life.

METHODS

This is a review of current clinical practice based on an exhaustive literature search of PubMed, Embase, and Google Scholar. A series of case studies is presented to provide outcomes of the effective management in BMs that have required treatment for the terminal stage of patients with cancer, and makes recommendations for future practice.

RESULTS

Current technical advances have been made in the diagnosis and treatment of BM. After surgery, radiotherapy, or stereotactic radiosurgery, and for some cases additional systemic chemotherapy for the primary cancer, most patients experience meaningful symptom relief, improved quality of life and longer survival time. An evidence-based summary of recommendations has been produced to guide neurosurgeons and oncologists in managing this particular group of patients.

CONCLUSIONS

On the basis of the available data, this treatment approach for well-selected patients is currently not recommended in the treatment of BMs except in experienced medical centers. Clinical judgment is made balancing surgical, radiotherapy, chemotherapy and management principles to advocacy the best therapy outcome.

Protein pathway activation mapping of brain metastasis from lung and breast cancers reveals organ type specific drug target activation

Brain metastases are the most common fatal complication of systemic cancer, especially of lung (40-50%) and breast (20-30%) cancers. In this era of personalized therapy, there is a critical need to uncover the signaling architecture of brain metastases; however, little is known about what signaling pathways are activated in the context of the brain microenvironment. Using a unique study set of 42 brain metastases from patients with breast or nonsmall cell lung cancer (NSCLC), the phosphorylation/activation states of 128 key signaling proteins involved in cancer signaling were measured in laser capture microdissected tumor epithelium using reverse phase protein microarray (RPMA) technology. Distinct pathway activation subgroups from both breast and lung metastases were underpinned by, among others, ERBB2, AKT, mTOR, EGFR, SMAD, and ERK-p38 signaling. Breast cancer metastases showed significantly (p < 0.05) higher activation of the c-ERBB2/IGFR-AKT pathway network compared to NSCLC metastases, whereas NSCLC metastases to the brain exhibited higher relative levels of many members of the EGFR-ERK signaling network. Protein pathway activation mapping using RPMA revealed both the heterogeneity of signaling networks in brain metastases that would require a prior stratification to targeted therapies as well as the requirement of direct analysis of the metastatic lesion.

Therapy and prophylaxis of brain metastases

Metastases of various tumors to the brain account for the majority of brain cancers, and are associated with a poor prognosis. The most common primary sites are lung, breast, skin, kidney and colon; 10-40% of cancer patients develop brain metastases during the course of the disease. The incidence of brain metastasis appears to be rising; reasons may include better therapies for the systemic disease with longer survival of cancer patients but lower efficiency against brain metastases. In this article, we will discuss the conventional treatment with surgery, radiosurgery, radiotherapy and chemotherapy, but also new directions in the management of solid brain metastases. While general therapeutic nihilism should be avoided, it is important to recognize that the number of brain metastases, the extent of the systemic disease and also the tumor type have to be taken into account when choosing individual treatment regimens. Finally, special emphasis will be put on established and future approaches to prevent the disease. We thus aim to provide a framework for treating patients with different presentations of brain metastases, and to highlight important avenues for research.

Preclinical approaches to study the biology and treatment of brain metastases

Metastatic spread to the central nervous system (CNS) is a common and devastating manifestation of major cancer types. Its incidence is associated with poor prognosis manifested by neurological deterioration leading to diminished quality of life and an extremely short median survival. CNS metastasis is becoming an increasingly important clinical problem. This is especially the case for certain types of cancers for which effective treatments of visceral disease are available. As a result of the present limitations in treating CNS metastases, this manifestation of tumor progression remains an unmet clinical need. Despite its significance, our general understanding of the mechanisms that regulate the brain-metastatic phenotype is currently meager. Both the analysis of mechanistic aspects of brain metastasis and the development of effective treatments necessitate the use of appropriate in vivo models that recapitulate the interaction of the tumor cells with the microenvironment of the brain. Here we review the available preclinical models of CNS metastasis and their use as tools to advance knowledge of the biology of the disease (with the aim of identifying relevant molecular determinants, prognostic biomarkers, and therapeutic targets) as well as examining effective approaches for treatment.

The Louisiana State University Experience in the Management of Single Small Cerebellar Metastasis

BACKGROUND:

Cerebellar metastasis is often believed to be a more immediately life-threatening complication than brain metastasis in other locations. It is considered a negative prognostic factor in patients with systemic cancers. Despite its clinical importance and technological advances, the survival outcomes of patients with single small cerebellar metastases are rarely studied.

OBJECTIVE:

To retrospectively evaluate our experience in the management of patients with single small cerebellar metastasis and compare the treatment modalities.

MATERIAL AND METHODS:

A total of 35 patients with single small cerebellar metastasis were included in this retrospective analysis. Of the 35 patients, 24 had surgery followed by whole-brain radiation therapy and 11 had Gamma Knife radiosurgery alone.

RESULTS:

The median survival for the whole cohort was 5.6 months after the intervention. No significant differences were noted in median survival between the surgery plus whole-brain radiation therapy and the Gamma Knife radiosurgery alone groups (6.3 months: 95% confidence interval [CI], 4.0-8.6; vs 5.0 months: 95% CI, 1.9-8.1; P = .9). There was no difference in the median time to local progression, distance progression, and overall progression between the 2 groups. Patients with hydrocephalus had a significantly lower survival rate (median, 3.3 months; 95% CI, 0.0-6.6) compared with those without hydrocephalus (median, 6.9 months; 95% CI, 4.4-9.8; P = .02). In the Cox regression model, the significant predictor of survival was hydrocephalus (P = .01; hazard ratio, 3.5; 95% CI, 1.3-9.1) after propensity score adjustment.

CONCLUSION:

Treatment with Gamma Knife radiosurgery alone and surgery plus whole-brain radiation therapy were both efficacious in patients with single small cerebellar metastasis. Overall survival was nearly identical in both treatment groups.

Selection bias introduced by neuropsychological assessments

OBJECTIVE

Two prospective studies in patient with brain tumours were performed comparing the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The first assessed their feasibility and the second compared their diagnostic accuracy against a four-hour neuropsychological assessment (NPA). The introduction of the NPA decreased accrual and retention rates. We were therefore concerned regarding potential selection bias.

METHODS

Ninety-two patients were prospectively accrued and subsequently divided into three categories: a) no NPA required b) withdrew consent to NPA c) completed NPA. In order to quantify any potential bias introduced by the NPA, patient demographics and cognitive test scores were compared between the three groups.

RESULTS

There were significant differences in age (p < 0.001), education (p = 0.034), dexamethasone use (p = 0.002), MMSE (p = 0.005), and MoCA scores (p < 0.001) across the different study groups. Furthermore, with increasing involvement of the NPA, patients' cognitive scores and educational status increased, while their age, dexamethasone use, and opioid use all decreased. Individuals who completed the NPA had higher MoCA scores than individuals who were not asked to complete the NPA (24.7 vs. 20.5; p < 0.001). In addition, this relationship held when restricting the analyses to individuals with brain metastases (p < 0.001).

CONCLUSIONS

In this study, the lengthy NPA chosen introduced a statistically and clinically significant source of selection bias. These results highlight the importance of selecting brief and well tolerated assessments when possible. However, researchers are challenged by weighing the improved selection bias associated with brief assessments at the cost of reduced diagnostic accuracy.

Translational research in brain metastasis is identifying molecular pathways that may lead to the development of new therapeutic strategies

Central nervous system (CNS) or brain metastasis is an emerging area of interest in organ-specific metastasis research. Lung and breast cancers are the most common types of primary tumors to develop brain metastases. This disease complication contributes significantly to the morbidity and mortality of both of these common cancers; as such, brain metastasis is designated an unmet medical need by the US Food and Drug Administration (FDA). Recently, an increase in incidence of CNS disease has been noted in the literature for breast cancer, while it has been an ongoing major complication from lung cancer. Progress in treating brain metastases has been hampered by a lack of model systems, a lack of human tissue samples, and the exclusion of brain metastatic patients from many clinical trials. While each of those is significant, the major impediment to effectively treating brain metastatic disease is the blood-brain barrier (BBB). This barrier excludes most chemotherapeutics from the brain and creates a sanctuary site for metastatic tumors. Recent findings on the biology of this disease and translational leads identified by molecular studies are discussed in this article.

The role of intra-cerebrospinal fluid treatment and prophylaxis in patients with solid tumors

Metastasis to the central nervous system (CNS), including neoplastic meningitis (NM), is a devastating complication of systemic cancer. With the improved survival of cancer patients, the incidence of CNS metastasis is rising, especially among those with breast or lung carcinoma. New therapies that effectively treat these primary tumors outside of the CNS have underscored the significance of CNS metastases; they have become a significant clinical issue and a therapeutic challenge. This review discusses clinical situations in which treatment or chemoprophylaxis of CNS metastases and NM from breast or lung cancer may play an important role. Potential clinical trials to assess these assumptions also will be proposed.