SNPs in the TGF-β signaling pathway are associated with increased risk of brain metastasis in patients with non-small-cell lung cancer

Nanotherapeutic strategy against glioblastoma using enzyme inhibitors

Glioblastoma is the most aggressive brain cancer and thus patients with glioblastoma have a severely low 5-year survival rate (<5 %). Glioblastoma damages neural centers, causing severe depression, anxiety, and cognitive disorders. Glioblastoma is highly resistant to most of available anti-tumor medications, due to heterogeneity of glioblastoma as well as the presence of stem-like cells. To overcome the challenges in the current medications against glioblastoma, novel medications that are effective in treating the aggressive and heterogenous glioblastoma should be developed. Enzyme inhibitor and nanomedicine have been getting attention because of effective anticancer efficacies of enzyme inhibitors and a role of nanomedicine as effective carrier of chemotherapeutic drugs by targeting specific tumor areas. Furthermore, a tumor-initiating neuroinflammatory microenvironment, which is crucial for glioblastoma progression, was linked with several carcinogenesis pathways. Therefore, in this review, first we summarize neuroinflammation and glioblastoma-related neuropathways. Second, we discuss the importance of enzyme inhibitors targeting specific proteins in relation with neuroinflammation and glioblastoma-related molecular mechanisms. Third, we summarize recent findings on the significance of nanotherapeutic anticancer drugs developed using natural or synthetic enzyme inhibitors against glioblastoma as well as currently available Food and Drug Administration (FDA)-approved drugs against glioblastoma.

Neuroprotective effect of Withania somnifera leaves extract nanoemulsion against penconazole-induced neurotoxicity in albino rats via modulating TGF-β1/Smad2 signaling pathway

Penconazole (PEN) is a systemic triazole fungicide used to control various fungal diseases on grapes, stone fruits, cucurbits, and strawberries. Still, it leaves residues on treated crops after collection with many hazardous effects on population including neurotoxicity. Withania somnifera leaves extract (WSLE) is known for its memory and brain function enhancing ability. To evoke such action efficiently, WSLE bioactive metabolites are needed to cross the blood-brain barrier, that could limit the availability of such compounds to be localized within the brain. Therefore, in the present study, the association between PEN exposure and neurotoxicity was evaluated, and formulated WSLE nanoemulsion was investigated for improving the permeability of the plant extract across the blood-brain barrier. The rats were divided into five groups (n = 6). The control group was administered distilled water, group II was treated with W. somnifera leaves extract nanoemulsion (WSLE NE), group III received PEN, group IV received PEN and WSLE, and group V received PEN and WSLE NE. All rats were gavaged daily for 6 weeks. Characterization of compounds in WSLE using LC-MS/MS analysis was estimated. Neurobehavioral disorders were evaluated in all groups. Oxidative stress biomarkers, antioxidant enzyme activities, and inflammatory cytokines were measured in brain tissue. Furthermore, the gene expression patterns of GFAP, APP, vimentin, TGF-β1, Smad2 and Bax were measured. Histopathological changes and immunohistochemical expression in the peripheral sciatic nerve and cerebral cortex were evaluated. A total of 91 compounds of different chemo-types were detected and identified in WSLE in both ionization modes. Our data showed behavioral impairment in the PEN-treated group, with significant elevation of oxidative stress biomarkers, proinflammatory cytokines, neuronal damage, and apoptosis. In contrast, the PEN-treated group with WSLE NE showed marked improvement in behavioral performance and histopathological alteration with a significant increase in antioxidant enzyme activity and anti-inflammatory cytokines compared to the group administered WSLE alone. The PEN-treated group with WSLE NE in turn significantly downregulated the expression levels of GFAP, APP, vimentin, TGF-β1, Smad2 and Bax in brain tissue. In conclusion, WSLE NE markedly enhanced the permeability of plant extract constituents through the blood brain barrier to boost its neuroprotective effect against PEN-induced neurotoxicity.

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

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

Immune related biomarkers for cancer metastasis to the brain

Brain metastasis accounts for a large number of cancer-related deaths. The host immune system, involved at each step of the metastatic cascade, plays an important role in both the initiation of the brain metastasis and their treatment responses to various modalities, through either local and or systemic effect. However, few reliable immune biomarkers have been identified in predicting the development and the treatment outcome in patients with cancer brain metastasis. Here, we provide a focused perspective of immune related biomarkers for cancer metastasis to the brain and a thorough discussion of the potential utilization of specific biomarkers such as tumor mutation burden (TMB), genetic markers, circulating and tumor-infiltrating immune cells, cytokines, in predicting the brain disease progression and regression after therapeutic intervention. We hope to inspire the field to extend the research and establish practical guidelines for developing and validating immune related biomarkers to provide personalized treatment and improve treatment outcomes in patients with metastatic brain cancers.

A germline SNP in BRMS1 predisposes patients with lung adenocarcinoma to metastasis and can be ameliorated by targeting c-fos

About 50% of patients with early-stage, surgically resected lung cancer will develop distant metastasis. There remains an unmet need to identify patients likely to develop recurrence and to design innovative therapies to decrease this risk. Two primary isoforms of BRMS1, v1 and v2, are present in humans. Using next-generation sequencing of BRMS1 on matched human noncancerous lung tissue and non-small cell lung cancer (NSCLC) specimens, we identified single-nucleotide polymorphism (SNP) rs1052566 that results in an A273V mutation of BRMS1v2. This SNP is homozygous (BRMS1v2^A273V/A273V) in 8% of the population and correlates with aggressive biology in lung adenocarcinoma (LUAD). Mechanistically, we show that BRMS1v2 A273V abolishes the metastasis suppressor function of BRMS1v2 and promotes robust cell invasion and metastases by activation of c-fos-mediated gene-specific transcriptional regulation. BRMS1v2 A273V increases cell invasion in vitro and increases metastases in both tail-vein injection xenografts and LUAD patient-derived organoid (PDO) intracardiac injection metastasis in vivo models. Moreover, we show that BRMS1v2 A273V fails to interact with nuclear Src, thereby activating intratumoral c-fos in vitro. Higher c-fos results in up-regulation of CEACAM6, which drives metastases in vitro and in vivo. Using both xenograft and PDO metastasis models, we repurposed T5224 for treatment, a c-fos pharmacologic inhibitor investigated in clinical trials for arthritis, and observed suppression of metastases in BRMS1v2^A273V/A273V LUAD in mice. Collectively, we elucidate the mechanism of BRMS1v2^A273V/A273V-induced metastases and offer a putative therapeutic strategy for patients with LUAD who have this germline alteration.

Smartphone-Based Platforms for Clinical Detections in Lung-Cancer-Related Exhaled Breath Biomarkers: A Review

Lung cancer has been studied for decades because of its high morbidity and high mortality. Traditional methods involving bronchoscopy and needle biopsy are invasive and expensive, which makes patients suffer more risks and costs. Various noninvasive lung cancer markers, such as medical imaging indices, volatile organic compounds (VOCs), and exhaled breath condensates (EBCs), have been discovered for application in screening, diagnosis, and prognosis. However, the detection of markers still relies on bulky and professional instruments, which are limited to training personnel or laboratories. This seriously hinders population screening for early diagnosis of lung cancer. Advanced smartphones integrated with powerful applications can provide easy operation and real-time monitoring for healthcare, which demonstrates tremendous application scenarios in the biomedical analysis region from medical institutions or laboratories to personalized medicine. In this review, we propose an overview of lung-cancer-related noninvasive markers from exhaled breath, focusing on the novel development of smartphone-based platforms for the detection of these biomarkers. Lastly, we discuss the current limitations and potential solutions.

Assessment of the Role of Selected SMAD3 and SMAD4 Genes Polymorphisms in the Development of Colorectal Cancer: Preliminary Research

Background

Colon cancer is one of the most common types of malignant tumor worldwide. The molecular mechanism of colorectal carcinogenesis is very complex and not yet fully understood. The TGFβ (transforming growth factor β) signaling pathway plays a significant role in the development of many cancers, including colorectal cancer pathogenesis. Changes in TGFβ pathway are associated with increased colorectal cancer risk, because this pathway participates in the control of important cellular processes such as cell growth, proliferation, differentiation, or apoptosis. The family of SMAD (similar to mother against decapentaplegic) proteins is closely correlated to this pathway. SMADs genes expression affects modulation of the transcription of many genes, which leads to the inhibition of cell-growth and apoptosis in colon epithelial cells. The presence of SNPs (single nucleotide polymorphisms) in SMADs genes encoding proteins involved in the control of biological processes important for the cell may play a significant role in the predisposition to the development of colorectal cancer, or in the regulation of the severity of changes related to tumor growth. Extension of data in this field may provide clinically significant conclusions influencing the implementation of personalized treatment based on specific changes characteristic of a patient with colorectal cancer.

Purpose

The subject of this research was genotyping polymorphisms of SMAD3 (rs6494629) and SMAD4 (rs10502913, rs12968012, rs1057520801) genes in the group of patients with colorectal cancer and in the control group, and comparing the genotypic frequency distributions with clinical-pathological features within the study group and between the groups.

Materials and Methods

SNP genotyping analysis was performed on genomic DNA isolated from 84 frozen tissue sections of colorectal cancer and from 60 peripheral blood samples of patients without cancer. To evaluate the polymorphic variants of SMAD genes, the restricted fragment length of a polymorphism reaction (PCR-RFLP) was used.

Results

The results obtained in the study showed no significant association between the examined polymorphisms and the risk of developing colorectal cancer.

Conclusion

More extensive studies to confirm the results obtained in this study are needed. Further studies on a larger study group divided according to the clinical stage and histological differentiation may allow finding or excluding the significance of the studied SNPs as potential markers of colorectal cancer in relation to the clinico-pathological data.

Advances in Lung Cancer Driver Genes Associated With Brain Metastasis

Brain metastasis, one of the common complications of lung cancer, is an important cause of death in patients with advanced cancer, despite progress in treatment strategies. Lung cancers with positive driver genes have higher incidence and risk of brain metastases, suggesting that driver events associated with these genes might be biomarkers to detect and prevent disease progression. Common lung cancer driver genes mainly encode receptor tyrosine kinases (RTKs), which are important internal signal molecules that interact with external signals. RTKs and their downstream signal pathways are crucial for tumor cell survival, invasion, and colonization in the brain. In addition, new tumor driver genes, which also encode important molecules closely related to the RTK signaling pathway, have been found to be closely related to the brain metastases of lung cancer. In this article, we reviewed the relationship between lung cancer driver genes and brain metastasis, and summarized the mechanism of driver gene-associated pathways in brain metastasis. By understanding the molecular characteristics during brain metastasis, we can better stratify lung cancer patients and alert those at high risk of brain metastasis, which helps to promote individual therapy for lung cancer.

The Network of Cytokines in Brain Metastases

Brain metastases are the most common of all intracranial tumors and a major cause of death in patients with cancer. Cytokines, including chemokines, interferons, interleukins, lymphokines, and tumor necrosis factors are key regulators in the formation of brain metastases. They regulate the infiltration of different cellular subsets into the tumor microenvironment and affect the therapeutic outcomes in patients. Elucidating the cancer cell-cytokine interactions in the setting of brain metastases is crucial for the development of more accurate diagnostics and efficacious therapies. In this review, we focus on cytokines that are found in the tumor microenvironment of brain metastases and elaborate on their trends of expression, regulation, and roles in cellular recruitment and tumorigenesis. We also explore how cytokines can alter the anti-tumor response in the context of brain metastases and discuss ways through which cytokine networks can be manipulated for diagnosis and treatment.

Systemic treatment of brain metastases in non-small cell lung cancer

Brain metastases (BrMs) are associated with significant morbidity and are found in up to 50% of patients with advanced non-small cell lung cancer (NSCLC). Most of the literature focuses on symptomatic BrMs, with a lack of baseline brain imaging in asymptomatic patients. Unfortunately, much of the data on local treatments with or without systemic treatment is retrospective. Clinical trials of systemic treatments largely exclude patients with BrMs. Chemotherapy is an active treatment for BrM with response rates in the brain similar to other sites of disease. Targeted systemic treatments in patients with driver mutations (EGFR and ALK-MET to date) have impressive central nervous system (CNS) penetrance and response rates. Unfortunately, no prospective data can currently guide the timings or modality of local therapies with systemic treatments in these patients who have a high incidence of CNS disease, but retrospective data suggest that early local therapies may give better intracranial progression-free survival (ICPFS). Recent immunotherapy trials have included patients with BrMs. These patients have largely been pre-treated with local therapies and are asymptomatic. Thus, the current standard is becoming, early local therapies before or in conjunction with immunotherapy agents. The approach seems to be safe. Prospective studies are needed in NSCLC BrMs patients to make sure any benefit from local therapies on the ICPFS and quality of life is not overlooked. Here we report what we think are reasonable conclusions from the available data and make suggestions for future clinical trials in the management of NSCLC BrMs.

Role of activin C in normal ovaries and granulosa cell tumours of mice and humans

Activins and inhibins play important roles in the development, growth and function of the ovary. Mice lacking inhibin develop granulosa cell tumours in their ovaries that secrete activin A, and these tumours are modulated by increased activin C expression. The aim of the present study was to identify where activin C is expressed in mouse and human ovaries and whether overexpression of activin C modulates normal follicular development in mice. Immunohistochemical staining for the activin βC subunit was performed on sections from mouse and human ovaries and human adult granulosa cell tumours. Stereology techniques were used to quantify oocyte and follicular diameters, and the percentage of different follicular types in ovaries from wild-type mice and those underexpressing inhibin α and/or overexpressing activin C. Staining for activin βC was observed in the oocytes, granulosa cells, thecal cells and surface epithelium of mouse and human ovaries, and in the granulosa-like cells of adult granulosa cell tumours. Overexpression of activin C in mice did not alter follicular development compared with wild-type mice, but it did modulate the development of abnormal early stage follicles in inhibin α-null mice. These results provide further evidence of a role for activin C in the ovary.

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.

The correlation between crizotinib efficacy and molecular heterogeneity by next-generation sequencing in non-small cell lung cancer

Background

Non-small cell lung cancer (NSCLC) patients with EML4-ALK fusion exhibited various durations of response to crizotinib. Molecular heterogeneity is also one of the factors associated with resistance to crizotinib. This study investigated the relevance of molecular heterogeneity to the clinical efficacy of crizotinib using next-generation sequencing (NGS).

Methods

A total of 52 ALK-positive advanced NSCLC patients were enrolled. The genetic variation was revealed by NGS. We identified different ALK fusion types, allelic fraction (AF) and additional coexisting mutations (ACMs) and evaluated the correlation between the above three factors and clinical response to crizotinib.

Results

Among the group that was detected with ALK+ fusion by immunohistochemistry (IHC), patients detected as ALK- fusion by the NGS method were associated with a shorter progression-free survival (PFS) compared with ALK+ patients by NGS. Moreover, for different ALK fusion types, the median PFS of variant 1/2/3 and other uncommon variants were 305, 557, 242 and 370 days, respectively. Although there was no statistically significant difference (P=0.201), patients with ALK variant 2 appeared to display a longer PFS than other types of variants in this study. There was no significant difference in the relationship between ALK fusion AF and PFS (P=0.639). Additionally, there was no correlation between ACMs and PFS in the three groups (IHC+, IHC+/NGS-, and IHC+/NGS+, P=0.738, 0.801 and 0.550). We analysed the relationship between TP53/FAT3 and PFS in the IHC+/NGS+ group, and there was no statistically significant difference (P=0.712/0.631).

Conclusions

It is necessary to use multiple methods together to detect ALK fusion, and we can continue to carry out the study of the correlation between the different contents of heterogeneity of gene mutations and TKI effects using the NGS method.

A Functional Variant of SMAD4 Enhances Thoracic Aortic Aneurysm and Dissection Risk through Promoting Smooth Muscle Cell Apoptosis and Proteoglycan Degradation

Recent studies indicate important roles for SMAD4 in SMCs proliferation, extracellular matrix maintenance, and blood vessel remodeling. However, the genetic effects of SMAD4 in the pathogenesis of thoracic aortic aneurysm and dissection (TAAD) are still largely unknown. Here we identified a functional variant of SMAD4 which might be involved in the pathological progression of TAAD. Five tagging SNPs of SMAD4 were genotyped in 202 TAAD cases and 400 controls using MALDI-TOF. rs12455792 CT or TT variant genotypes was associated with an significantly elevated TAAD risk (adjusted OR = 1.58, 95%CI = 1.09–2.30) under a dominant genetic model. It was located in the 5’UTR and predicted to influence transcription activity and RNA folding of SMAD4. In luciferase reporter assay, rs12455792 T allele markedly decreased luciferase activities. Accordingly, SMAD4 expression in tissues was lower in patients with CT or TT genotypes, compared with CC. Movat's pentachrome showed that rs12455792 T allele enhanced SMCs loss and fibers accumulation. With angiotensin II induction, rate of Apoptotic SMCs was significantly higher while SMAD4 silenced. Moreover, rs12455792 T allele also increased Versican degradation via ADAMTS-4. In conclusion, this variant might promote SMCs apoptosis and proteoglycans degradation, and further facilitate the progress of TAAD. Our findings identified rs12455792 as a predictor for progression of vascular media pathological changes related thoracic aortic disorders.

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The variant on 5'UTR of SMAD4 gene significantly increased thoracic aortic aneurysm and dissection risk.

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The variant rs12455792 reduced SMAD4 expression and influenced its effects on proteoglycans degradation, SMCs apoptosis and fiber accumulation.

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rs1rs12455792 might be a potential therapeutic marker in vascular media pathological changes related thoracic aortic disorders.

Understanding the genetic features of thoracic aortic aneurysm and dissection can lead to precision surgery strategy. In this study, we demonstrated that SMAD4 rs12455792 is located in the transcription factor binding site and the allele change influences transcription activity and SMAD4 expression. Decrease of SMAD4 expression promotes proteoglycans degradation, vascular SMCs apoptosis and fiber accumulation, which are involved in pathological progression of TAAD. rs12455792 might be a potential therapeutic marker in vascular media pathological changes related thoracic aortic disorders.

The Thr300Ala variant of ATG16L1 is associated with decreased risk of brain metastasis in patients with non-small cell lung cancer

Non-small cell lung cancer (NSCLC) often metastasizes to the brain, but identifying which patients will develop brain metastases (BM) is difficult. Macroautophagy/autophagy is critical for cancer initiation and progression. We hypothesized that genetic variants of autophagy-related genes may affect brain metastases (BM) in NSCLC patients. We genotyped 16 single nucleotide polymorphisms (SNPs) in 7 autophagy-related (ATG) genes (ATG3, ATG5, ATG7, ATG10, ATG12, ATG16L1, and MAP1LC3/LC3) by using DNA from blood samples of 323 NSCLC patients. Further, we evaluated the potential associations of these genes with subsequent BM development. Lung cancer cell lines stably transfected with ATG16L1: rs2241880 (T300A) were established. Mouse models of brain metastasis were developed using cells transfected with ATG16L1-300T or ATG16L1-300A. ATG10: rs10036653 and ATG16L1: rs2241880 were significantly associated with a decreased risk of BM (respective hazard ratios [HRs]=0.596, 95% confidence interval [CI] 0.398-0.894, P = 0.012; and HR = 0. 655, 95% CI 0.438-0.978, P = 0.039, respectively). ATG12: rs26532 was significantly associated with an increased risk of BM (HR=1.644, 95% CI 1.049-2.576, P = 0.030). Invasion and migration assays indicated that transfection with ATG16L1-300T (vs. 300A) stimulated the migration of A549 cells. An in vivo metastasis assay revealed that transfection with ATG16L1-300T (vs. 300A) significantly increased brain metastasis. Our results indicate that genetic variations in autophagy-related genes can predict BM and that genome analysis would facilitate stratification of patients for BM prevention trials.

Progression and metastasis of lung cancer

Metastasis in lung cancer is a multifaceted process. In this review, we will dissect the process in several isolated steps such as angiogenesis, hypoxia, circulation, and establishment of a metastatic focus. In reality, several of these processes overlap and occur even simultaneously, but such a presentation would be unreadable. Metastasis requires cell migration toward higher oxygen tension, which is based on changing the structure of the cell (epithelial-mesenchymal transition), orientation within the stroma and stroma interaction, and communication with the immune system to avoid attack. Once in the blood stream, cells have to survive trapping by the coagulation system, to survive shear stress in small blood vessels, and to find the right location for extravasation. Once outside in the metastatic locus, tumor cells have to learn the communication with the “foreign” stroma cells to establish vascular supply and again express molecules, which induce immune tolerance.

The molecular biology of lung cancer brain metastasis: an overview of current comprehensions and future perspectives

Brain metastases occur in 20-40% of patients with advanced malignancies and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity in patients with advanced lung cancer, even after intensive multimodal therapy. 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 the biology of brain metastasis is still poorly understood, it is encouraging to see more efforts are beginning to be directed toward the study of brain metastasis. During the multi-step process of metastasis, functional significance of gene expressions, changes in brain vasculature, abnormal secretion of soluble factors and activation of autocrine/paracrine signaling are considered to contribute to the brain metastasis development. A better understanding of the mechanism of this disease will help us to identify the appropriate therapeutic strategies, which leads to circumvent brain metastases. Recent findings on the biology of lung cancer brain metastases and translational leads identified by molecular studies are discussed in this review.

Association between brain metastasis from lung cancer and the serum level of myelin basic protein

The aim of the present study was to determine the association between the expression of myelin basic protein in the serum and the metastasis of lung cancer to the brain. A total of 68 lung cancer patients, treated in the Department of Respiratory Medicine of the People’s Hospital of Rizhao (Rizhao, China), were divided into two groups, those with brain metastasis (32 cases) and those without brain metastasis (36 cases). The expression levels of myelin basic protein were measured for all the patients. The results indicated that the expression levels of myelin basic protein in the brain metastasis group were significantly higher when compared with those in the group without metastasis (P<0.05). However, there was no statistically significant correlation between the size of the brain metastasis and the expression levels of myelin basic protein (P>0.05). Furthermore, no statistically significant difference was found in the average level of myelin basic protein between the two subgroups of patients with brain tumor diameters of >1.5 cm and <1.5 cm (P>0.05). Therefore, the results demonstrated a statistically significant correlation between the expression of myelin basic protein in the serum and the metastasis of lung cancer to the brain. Myelin basic protein may thus prove useful in the early diagnosis of brain metastases in lung cancer patients.

Value of oncogenes for the prediction of brain metastases at initial diagnosis: a review of published data

Identifying cancer patients who are at high risk of developing brain metastases at initial diagnosis and applying effective intervention or monitoring strategies is of vital importance. Recent advances in the biology of brain metastases revealed that some oncogenes from primary tumors may be potential markers for identifying cancer patients likely to metastasize to the brain. We here summarize data on the mechanisms of brain metastases supporting the involvement of oncogene changes in the brain metastatic evolution. We also review the available evidence on clinical studies of oncogenes in the prediction of cancer patients with high incidence of brain metastases.

Associations between single-nucleotide polymorphisms in the PI3K-PTEN-AKT-mTOR pathway and increased risk of brain metastasis in patients with non-small cell lung cancer

PURPOSE

Non-small cell lung cancer (NSCLC) metastasizes fairly often to the brain, but identifying which patients will develop brain metastases is problematic. The phosphoinositide 3-kinase (PI3K)-AKT-mTOR signaling pathway is important in the control of cell growth, tumorigenesis, and cell invasion. We hypothesized that genotype variants in this pathway could predict brain metastasis in patients with NSCLC.

METHODS

We genotyped 16 single-nucleotide polymorphisms (SNP) in five core genes (PIK3CA, PTEN, AKT1, AKT2, and FRAP1) by using DNA from blood samples of 317 patients with NSCLC, and evaluated potential associations with the subsequent development of brain metastasis, the cumulative incidence of which was estimated with Kaplan-Meier analysis. Multivariate Cox regression analysis was used to analyze correlations between genotype variants and the occurrence of brain metastasis.

RESULTS

In analysis of individual SNPs, the GT/GG genotype of AKT1: rs2498804, CT/TT genotype of AKT1: rs2494732, and AG/AA genotype of PIK3CA: rs2699887 were associated with higher risk of brain metastasis at 24-month follow-up [respective HRs, 1.860, 95% confidence interval (CI) 1.199-2.885, P = 0.006; HR 1.902, 95% CI 1.259-2.875, P = 0.002; and HR 1.933, 95% CI 1.168-3.200, P = 0.010]. We further found that these SNPs had a cumulative effect on brain metastasis risk, with that risk being highest for patients carrying both of these unfavorable genotypes (P = 0.003).

CONCLUSIONS

Confirmation of our findings, the first to indicate that genetic variations in PI3K-AKT-mTOR can predict brain metastasis, in prospective studies would facilitate stratification of patients for brain metastasis prevention trials.

Predictive biochemical-markers for the development of brain metastases from lung cancer: clinical evidence and future directions

BACKGROUND

Brain metastases are a common complication of patients with lung cancer and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity, even after intensive multimodal therapy. Therefore, identifying lung cancer patients with who are at high risk of developing brain metastases and applying effect intervention is important to reduce or delay the incidence of brain metastases. Biochemical-markers may meet an unmet need for following patients' mechanisms of brain metastases.

METHODS

Data for this review were identified by searches of Pubmed and Cochrane databases, and references from relevant articles using the search terms "lung cancer" and "brain metastasis". Meeting abstracts, unpublished reports and review articles were not considered.

RESULTS

Clinical results for pathological and circulating markers including cancer molecular subtypes, miRNA, single nucleotide polymorphisms, and other markers are presented. However, these biochemical-markers are not yet established surrogate assessments for prediction of brain metastases.

CONCLUSIONS

Biochemical-markers reported allowed physicians to identify which patients with lung cancer are at high risk for brain metastases. Prospective randomized clinical studies are needed to further assess the utility of these biochemical-markers.