A gene expression signature associated with metastatic cells in effusions of breast carcinoma patients

Time interval between the diagnosis of breast cancer and brain metastases impacts prognosis after metastasis surgery

Purpose

Breast cancer (BC) is the most frequently diagnosed tumor entity in women. Occurring at different time intervals (TI) after BC diagnosis, brain metastases (BM) are associated with poor prognosis. We aimed to identify the risk factors related to and the clinical impact of timing on overall survival (OS) after BM surgery.

Methods

We included 93 female patients who underwent BC BM surgery in our institution (2008–2019). Various clinical, radiographic, and histopathologic markers were analyzed with respect to TI and OS.

Results

The median TI was 45.0 months (range: 9–334.0 months). Fifteen individuals (16.1%) showed late occurrence of BM (TI ≥ 10 years), which was independently related to invasive lobular BC [adjusted odds ratio (aOR) 9.49, 95% confidence interval (CI) 1.47–61.39, p = 0.018] and adjuvant breast radiation (aOR 0.12, 95% CI 0.02–0.67, p = 0.016). Shorter TI (< 5 years, aOR 4.28, 95% CI 1.46–12.53, p = 0.008) was independently associated with postoperative survival and independently associated with the Union for International Cancer Control stage (UICC) III–IV of BC (aOR 4.82, 95% CI 1.10–21.17, p = 0.037), midline brain shift in preoperative imaging (aOR10.35, 95% CI 1.09–98.33, p = 0.042) and identic estrogen receptor status in BM (aOR 4.56, 95% CI 1.35–15.40, p = 0.015).

Conclusions

Several factors seem to influence the period between BC and BM. Occurrence of BM within five years is independently associated with poorer prognosis after BM surgery. Patients with invasive lobular BC and without adjuvant breast radiation are more likely to develop BM after a long progression-free survival necessitating more prolonged cancer aftercare of these individuals.

Prediction of Short and Long Survival after Surgery for Breast Cancer Brain Metastases

Background: Brain metastases requiring surgical treatment determine the prognosis of patients with breast cancer. We aimed to develop the scores for the prediction of short (<6 months) and long (≥3 years) survival after BCBM surgery. Methods: Female patients with BCBM surgery between 2008 and 2019 were included. The new scores were constructed upon independent predictors for short and long postoperative survival. Results: In the final cohort (n = 95), 18 (18.9%) and 22 (23.2%) patients experienced short and long postoperative survival, respectively. Breast-preserving surgery, presence of multiple brain metastases and age ≥ 65 years at breast cancer diagnosis were identified as independent predictors of short postoperative survival. In turn, positive HER2 receptor status in brain metastases, time interval ≥ 3 years between breast cancer and brain metastases diagnosis and KPS ≥ 90% independently predicted long survival. The appropriate short and long survival scores showed higher diagnostic accuracy for the prediction of short (AUC = 0.773) and long (AUC = 0.775) survival than the breast Graded Prognostic Assessment score (AUC = 0.498/0.615). A cumulative survival score (total score) showed significant association with overall survival (p = 0.001). Conclusion: We identified predictors independently impacting the prognosis after BCBM surgery. After external validation, the presented scores might become useful tools for the selection of proper candidates for BCBM surgery.

Minimal residual disease in prostate cancer patients after primary treatment: theoretical considerations, evidence and possible use in clinical management

Minimal residual disease is that not detected by conventional imaging studies and clinically the patient remains disease free. However, with time these dormant cells will awaken and disease progression occurs, resulting in clinically and radiological detectable metastatic disease. This review addresses the concept of tumor cell dissemination from the primary tumor, the micrometastatic niche and tumor cell survival and finally the clinical utility of detecting and characterizing these tumor cells in order to guide management decisions in treating patients with prostate cancer.

CXCL12 chemokine and CXCR4 receptor: association with susceptibility and prognostic markers in triple negative breast cancer

CXCL12/CXCR4 signaling has been implicated in breast carcinogenesis, and genetic polymorphisms in these molecules have been associated with different types of cancer. The present study analyzed genetic polymorphisms in CXCL12 (rs1801157, G > A) and CXCR4 (rs2228014, C > T) and CXCR4 immunostaining in tumor tissues from patients with triple negative breast cancer (TNBC) aiming to evaluate their possible role in its' susceptibility and prognosis. Genetic polymorphisms were analyzed in 59 TNBC patients and 150 control women; age-adjusted logistic regression showed no association when variants were considered in isolation; however, a statistically significant interaction was noted for heterozygosis for both allelic variants increasing the odds for TNBC (CXCL12-GA by CXCR4-CT: OR 7.23; 95% CI 1.15-45.41; p = 0.035). CXCL12 polymorphism was correlated negatively with proliferation index (Ki67) (Tau-b = - 0.406; p = 0.006). CXCR4 immunostaining was evaluated in 37 TNBC patients (22 with paired tumor-normal adjacent tissue). CXCR4 was detected more intensely in cell cytoplasm than in membrane, and was more expressed in tumor than in normal adjacent tissues, although not statistically significant. CXCR4 expression on the membrane of tumor cells was correlated positively with histopathological grade (Tau-b = 0.271; p = 0.036) and negatively with lymph node metastasis (Tau-b = - 0.478; p = 0.036). The present study indicates that CXCL12 and CXCR4 polymorphisms and CXCR4 immunostaining might have susceptibility and prognostic roles in TNBC pathogenesis.

CXCL12 gene silencing down-regulates metastatic potential via blockage of MAPK/PI3K/AP-1 signaling pathway in colon cancer

Background

To investigate the effect of CXCL12 gene silencing on proliferation,invasion, angiogenesis and the relationship of MAPK/PI3K/AP-1 signaling pathway in colon cancer cells.

Methods

RT-PCR and Western-blot were used to detect the expression of CXCL12 mRNA and protein in four colon cancer cell lines. Human colon cancer cells were transfected with CXCL12 siRNA carrying by Lipofectamine 2000. The expression of CXCL12 protein was confirmed by immunoblotting. WST-1, invasion and angiogenesis assay were used to examine the effect on proliferation, invasion and angiogenesis in colon cancer cells after CXCL12 siRNA silence, respectively. The phosphorylation of MAPK/PI3K/AP-1 protein levels was detected by Western blotting in CXCL12 siRNA suppression DLD-1 cell.

Results

CXCL12 mRNA and proteins were only expressed in DLD-1 colon cancer cell lines. CXCL12 siRNA were transfected into DLD-1 cells, the expression CXCL12 proteins was significantly inhibited (P < 0.01), and the proliferation, invasion and angiogenesis of DLD-1 cells were inhibited significantly (P < 0.01). CXCL12 gene silencing resulted in blockage of MAPK, PI3K and AP-1 phosphorylation by CXCL12-induced in DLD-1 colon cancer cell.

Conclusion

The silencing CXCL12 gene significantly inhibits the proliferation, invasion and angiogenesis ability of some types colon carcinoma cells through down-regulation of MAPK/PI3K/AP-1 signaling pathway.

Prognostic significance of CD24 and CD44 in breast cancer: a meta-analysis

OBJECTIVE

Numerous studies have focused on the prognostic roles of CD24 and CD44 in breast cancer, but the results have been equivocal. The aim of this study was to gain better insight into the relationship between expression of CD24 and of CD44, either alone or in combination, and prognostic parameters in breast cancer.

METHODS

Publications addressing the associations of CD24 or CD44 expression with survival outcome in breast cancer were selected for the meta-analysis according to defined criteria. Studies were pooled and odds ratios (ORs) or hazard ratios (HRs) were calculated. Publication bias and sensitivity analyses were also conducted.

RESULTS

Sixteen studies comprising 5,697 breast cancer cases were included in our meta-analysis. Overall, CD24 overexpression was significantly associated with histological grade (OR = 1.52; 95% CI 1.12-2.06, p = 0.007), stage (OR = 1.74; 95% CI 1.27-2.40, p<0.001), shortened overall survival (HR = 1.48; 95% CI 1.21-1.80, p<0.001) and disease-free survival (HR 1.45, 95% CI 1.19-1.76, p<0.001), while no such association was observed when we limited our analysis to CD44 and CD44+/CD24- phenotypes. Subgroup analyses for CD24 according to the studies categorized by ethnicity, staining patterns and follow-up period were also conducted, and supported the stability of the prognostic role of CD24.

CONCLUSIONS

Our study demonstrated that the putative stem cell marker CD24 was significantly associated with worse survival based on the obtained data. In particular, CD24 may play a role in tumorigenesis and cancer progression. However, further large-scale studies are needed to confirm these findings.

Minimal residual disease in breast cancer: an overview of circulating and disseminated tumour cells

Within the field of cancer research, focus on the study of minimal residual disease (MRD) in the context of carcinoma has grown exponentially over the past several years. MRD encompasses circulating tumour cells (CTCs)—cancer cells on the move via the circulatory or lymphatic system, disseminated tumour cells (DTCs)—cancer cells which have escaped into a distant site (most studies have focused on bone marrow), and resistant cancer cells surviving therapy—be they local or distant, all of which may ultimately give rise to local relapse or overt metastasis. Initial studies simply recorded the presence and number of CTCs and DTCs; however recent advances are allowing assessment of the relationship between their persistence, patient prognosis and the biological properties of MRD, leading to a better understanding of the metastatic process. Technological developments for the isolation and analysis of circulating and disseminated tumour cells continue to emerge, creating new opportunities to monitor disease progression and perhaps alter disease outcome. This review outlines our knowledge to date on both measurement and categorisation of MRD in the form of CTCs and DTCs with respect to how this relates to cancer outcomes, and the hurdles and future of research into both CTCs and DTCs.

Chemotherapeutic agents attenuate CXCL12-mediated migration of colon cancer cells by selecting for CXCR4-negative cells and increasing peptidase CD26

Background

Recurrence of colorectal cancer (CRC) may arise due to the persistence of drug-resistant and cancer-initiating cells that survive exposure to chemotherapy. Proteins responsible for this recurrence include the chemokine receptor CXCR4, which is known to enable CRC metastasis, as well as the cancer-initiating cell marker and peptidase CD26, which terminates activity of its chemokine CXCL12.

Methods

We evaluated the expression and function of CXCR4 and CD26 in colon cancer cell lines and xenografts following treatment with common chemotherapies using radioligand binding, flow cytometry, immunofluorescence, and enzymatic assays.

Results

5-Fluorouracil, oxaliplatin and SN-38 (the active metabolite of irinotecan), as well as cisplatin, methotrexate and vinblastine, each caused decreases in cell-surface CXCR4 and concomitant increases in CD26 on HT-29, T84, HRT-18, SW480 and SW620 CRC cell lines. Flow cytometry indicated that the decline in CXCR4 was associated with a significant loss of CXCR4+/CD26- cells. Elevations in CD26 were paralleled by increases in both the intrinsic dipeptidyl peptidase activity of CD26 as well as its capacity to bind extracellular adenosine deaminase. Orthotopic HT-29 xenografts treated with standard CRC chemotherapeutics 5-fluorouracil, irinotecan, or oxaliplatin showed dramatic increases in CD26 compared to untreated tumors. Consistent with the loss of CXCR4 and gain in CD26, migratory responses to exogenous CXCL12 were eliminated in cells pretreated with cytotoxic agents, although cells retained basal motility. Analysis of cancer-initiating cell CD44 and CD133 subsets revealed drug-dependent responses of CD26/CD44/CD133 populations, suggesting that the benefits of combining standard chemotherapies 5-fluoruracil and oxaliplatin may be derived from their complementary elimination of cell populations.

Conclusion

Our results indicate that conventional anticancer agents may act to inhibit chemokine-mediated migration through eradication of CXCR4+ cells and attenuation of chemokine gradients through elevation of CD26 activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1702-2) contains supplementary material, which is available to authorized users.

Cell specific CD44 expression in breast cancer requires the interaction of AP-1 and NFκB with a novel cis-element

Breast cancers contain a heterogeneous population of cells with a small percentage that possess properties similar to those found in stem cells. One of the widely accepted markers of breast cancer stem cells (BCSCs) is the cell surface marker CD44. As a glycoprotein, CD44 is involved in many cellular processes including cell adhesion, migration and proliferation, making it pro-oncogenic by nature. CD44 expression is highly up-regulated in BCSCs, and has been implicated in tumorigenesis and metastasis. However, the genetic mechanism that leads to a high level of CD44 expression in breast cancer cells and BCSCs is not well understood. Here, we identify a novel cis-element of the CD44 directs gene expression in breast cancer cells in a cell type specific manner. We have further identified key trans-acting factor binding sites and nuclear factors AP-1 and NFκB that are involved in the regulation of cell-specific CD44 expression. These findings provide new insight into the complex regulatory mechanism of CD44 expression, which may help identify more effective therapeutic targets against the breast cancer stem cells and metastatic tumors.

MLK3 regulates paxillin phosphorylation in chemokine-mediated breast cancer cell migration and invasion to drive metastasis

MLK3 kinase activates multiple mitogen-activated protein kinases and plays a critical role in cancer cell migration and invasion. In the tumor microenvironment, prometastatic factors drive breast cancer invasion and metastasis, but their associated signaling pathways are not well-known. Here, we provide evidence that MLK3 is required for chemokine (CXCL12)-induced invasion of basal breast cancer cells. We found that MLK3 induced robust phosphorylation of the focal adhesion scaffold paxillin on Ser 178 and Tyr 118, which was blocked by silencing or inhibition of MLK3-JNK. Silencing or inhibition of MLK3, inhibition of JNK, or expression of paxillin S178A all led to enhanced Rho activity, indicating that the MLK3-JNK-paxillin axis limits Rho activity to promote focal adhesion turnover and migration. Consistent with this, MLK3 silencing increased focal adhesions and stress fibers in breast cancer cells. MLK3 silencing also decreased the formation of breast cancer lung metastases in vivo, and breast cancer cells derived from mouse lung metastases showed enhanced Ser 178 paxillin phosphorylation. Taken together, our findings suggest that the MLK3-JNK-paxillin signaling axis may represent a potential therapeutic target and/or prognostic marker in breast cancer metastasis.

The challenge of gene expression profiling in heterogeneous clinical samples

Almost all samples used in tumor biology, such as tissues and bodily fluids, are heterogeneous, i.e., consist of different cell types. Evaluating the degree of heterogeneity in samples can increase our knowledge on processes such as clonal selection and metastasis. In addition, generating expression profiles from specific sub populations of cells can reveal their distinct functions. Tissue heterogeneity also poses a challenge, as it can confound the interpretation of gene expression data. This chapter will (1) give a brief overview on how heterogeneity may influence gene expression profiling data and (2) describe the methods that are currently available to assess transcriptional biomarkers in a heterogeneous cell population.

Relevance of PTEN loss in brain metastasis formation in breast cancer patients

INTRODUCTION

With the improvement of therapeutic options for the treatment of breast cancer, the development of brain metastases has become a major limitation to life expectancy in many patients. Therefore, our aim was to identify molecular markers associated with the development of brain metastases in breast cancer.

METHODS

Patterns of chromosomal aberrations in primary breast tumors and brain metastases were compared with array-comparative genetic hybridization (CGH). The most significant region was further characterized in more detail by microsatellite and gene-expression analysis, and finally, the possible target gene was screened for mutations.

RESULTS

The array CGH results showed that brain metastases, in general, display similar chromosomal aberrations as do primary tumors, but with a notably higher frequency. Statistically significant differences were found at nine different chromosomal loci, with a gain and amplification of EGFR (7p11.2) and a loss of 10q22.3-qter being among the most significant aberrations in brain metastases (P < 0.01; false discovery rate (fdr) < 0.04). Allelic imbalance (AI) patterns at 10q were further verified in 77 unmatched primary tumors and 21 brain metastases. AI at PTEN loci was found significantly more often in brain metastases (52%) and primary tumors with a brain relapse (59%) compared with primary tumors from patients without relapse (18%; P = 0.003) or relapse other than brain tumors (12%; P = 0.006). Loss of PTEN was especially frequent in HER2-negative brain metastases (64%). Furthermore, PTEN mRNA expression was significantly downregulated in brain metastases compared with primary tumors, and PTEN mutations were frequently found in brain metastases.

CONCLUSIONS

These results demonstrate that brain metastases often show very complex genomic-aberration patterns, suggesting a potential role of PTEN and EGFR in brain metastasis formation.

Osteopontin--an important downstream effector of S100A4-mediated invasion and metastasis

Substantial evidence has linked the small calcium-binding protein S100A4 to metastatic progression. S100A4-mediated effects include stimulation of angiogenesis, regulation of cell death and increased cell motility and invasion, but the exact molecular mechanisms by which the protein exerts these effects are incompletely elucidated. In the present study, we demonstrate that S100A4 induces NF-κB-dependent expression and secretion of osteopontin (OPN) in a selection of osteosarcoma cell lines. OPN is, as S100A4, known to result in a variety of cellular effects potentially leading to increased angiogenesis and metastasis, and several of the activated signaling pathways are common for the two proteins. In our study, extracellular S100A4 was found to upregulate enzymes of the plasminogen activator system and matrix metalloproteinase (MMP) family, especially urokinase plasminogen activator and MMP-13. Furthermore, increased motility and invasion was observed in vitro as a result of S100A4 treatment. OPN expression was inhibited by the use of siRNA molecules, and a partial blocking of S100A4-induced effects on protease expression and invasive capacity was detected. In conclusion, our results suggest regulation of OPN as a downstream molecular mechanism of S100A4 signaling. This novel finding adds more information to how S100A4 mediates tumor development and metastatic progression. The observation of a link between S100A4 and OPN, and also identification of common downstream effect molecules, highlights them, their receptors or downstream proteins, as targets for therapeutic approaches.

CXCR4 in Cancer and Its Regulation by PPARgamma

Chemokines are peptide mediators involved in normal development, hematopoietic and immune regulation, wound healing, and inflammation. Among the chemokines is CXCL12, which binds principally to its receptor CXCR4 and regulates leukocyte precursor homing to bone marrow and other sites. This role of CXCL12/CXCR4 is “commandeered” by cancer cells to facilitate the spread of CXCR4-bearing tumor cells to tissues with high CXCL12 concentrations. High CXCR4 expression by cancer cells predisposes to aggressive spread and metastasis and ultimately to poor patient outcomes. As well as being useful as a marker for disease progression, CXCR4 is a potential target for anticancer therapies. It is possible to interfere directly with the CXCL12:CXCR4 axis using peptide or small-molecular-weight antagonists. A further opportunity is offered by promoting strategies that downregulate CXCR4 pathways: CXCR4 expression in the tumor microenvironment is modulated by factors such as hypoxia, nucleosides, and eicosanoids. Another promising approach is through targeting PPAR to suppress CXCR4 expression. Endogenous PPARγ such as 15-deoxy-Δ^12,14-PGJ₂ and synthetic agonists such as the thiazolidinediones both cause downregulation of CXCR4 mRNA and receptor. Adjuvant therapy using PPARγ agonists may, by stimulating PPARγ-dependent downregulation of CXCR4 on cancer cells, slow the rate of metastasis and impact beneficially on disease progression.

Different prognostic significance of CD24 and CD44 expression in breast cancer according to hormone receptor status

OBJECTIVE

CD44(+)CD24(-/low)-expressing tumor cells have been studied as tumorigenic stem cells in vitro study. This study was designed to determine the clinical implication of the CD44 and CD24 expression in breast cancer.

METHODS

Tissue microarray blocks containing 643 consecutive cases of invasive breast carcinomas from 1993 to 1998 were immunostained for CD44 and CD24. The median follow-up period was 127 months.

RESULTS

CD44(-)CD24(+) phenotype was associated with frequent hormone receptor positivity and Her2/neu positivity (P = 0.000; Both). The CD44(+)CD24(-) phenotype was inversely associated with lymph node metastasis (P = 0.002), and it showed positive associations with prolonged disease-free survival (DFS; P = 0.003) and overall survival (OS; P = 0.002). 10-year DFS and OS were 68.9% and 74.6% for CD24 negative group, 55.6% and 60.9% for CD24 positive group (P = 0.001; Both). 10-year DFS and OS were 62.2% and 68.1% for CD44 negative group, 73% and 77.7% for CD44 positive group (P = 0.012, P = 0.013, respectively). In a multivariate analysis, CD24 expression was negatively related to OS only in the receptor positive group (Hazard ratio = 2.03; P = 0.003; 95% CI: 1.27-3.24) and CD44 expression was positively related to OS only in the hormone receptor negative group (hazard ratio = 0.58; P = 0.022; 95% CI: 0.36-0.92).

CONCLUSIONS

The CD44(+)CD24(-) group is considered a favorable prognostic subgroup in breast cancer. CD24 expression was a poor prognosis marker in hormone receptor positive breast cancer, and CD44 expression was a good prognostic marker in the receptor negative group.

Breast carcinoma cells in primary tumors and effusions have different gene array profiles

The detection of breast carcinoma cells in effusions is associated with rapidly fatal outcome, but these cells are poorly characterized at the molecular level. This study compared the gene array signatures of breast carcinoma cells in primary carcinomas and effusions. The genetic signature of 10 primary tumors and 10 effusions was analyzed using the Array-Ready Oligo set for the Human Genome platform. Results for selected genes were validated using PCR, Western blotting, and immunohistochemistry. Array analysis identified 255 significantly downregulated and 96 upregulated genes in the effusion samples. The majority of differentially expressed genes were part of pathways involved in focal adhesion, extracellular matrix-cell interaction, and the regulation of the actin cytoskeleton. Genes that were upregulated in effusions included KRT8, BCAR1, CLDN4, VIL2, while DCN, CLDN19, ITGA7, and ITGA5 were downregulated at this anatomic site. PCR, Western blotting, and immunohistochemistry confirmed the array findings for BCAR1, CLDN4, VIL2, and DCN. Our data show that breast carcinoma cells in primary carcinomas and effusions have different gene expression signatures, and differentially express a large number of molecules related to adhesion, motility, and metastasis. These differences may have a critical role in designing therapy and in prognostication for patients with metastatic disease localized to the serosal cavities.

Global gene expression profiling unveils S100A8/A9 as candidate markers in H-ras-mediated human breast epithelial cell invasion

The goal of the present study is to unveil the gene expression profile specific to the biological processes of human breast epithelial cell invasion and migration using an MCF10A model genetically engineered to constitutively activate the H-ras or N-ras signaling pathway. We previously showed that H-Ras, but not N-Ras, induces MCF10A cell invasion/migration, whereas both H-Ras and N-Ras induce cell proliferation and phenotypic transformation. Thus, these cell lines provide an experimental system to separate the gene expression profile associated with cell invasion apart from cell proliferation/transformation. Analysis of whole human genome microarray revealed that 412 genes were differentially expressed among MCF10A, N-Ras MCF10A, and H-Ras MCF10A cells and hierarchical clustering separated 412 genes into four clusters. We then tested whether S100A8 and S100A9, two of the genes which are most highly up-regulated in an H-Ras-specific manner, play a causative role for H-Ras-mediated MCF10A cell invasion and migration. Importantly, small interfering RNA-mediated knockdown of S100A8/A9 expression significantly reduced H-Ras-induced invasion/migration. Conversely, the induction of S100A8/A9 expression conferred the invasive/migratory phenotype to parental MCF10A cells. Furthermore, we provided evidence of signaling cross-talk between S100A8/A9 and the mitogen-activated protein kinase signaling pathways essential for H-Ras-mediated cell invasion and migration. Taken together, this study revealed S100A8/A9 genes as candidate markers for metastatic potential of breast epithelial cells. Our gene profile data provide useful information which may lead to the identification of additional potential targets for the prognosis and/or therapy of metastatic breast cancer.

Comparative analysis of protein expressions in primary and metastatic gastric carcinomas

Because metastatic cancers are derived from their primary counterparts, their molecular profiles could reasonably be expected to be similar to those of primary cancers. However, this expectation has been proven to be untrue in several human cancers. To explore protein expressional differences in primary and metastatic gastric carcinoma, we evaluated the expressions of 32 tumor-associated proteins in 250 pairs of primary and metastatic gastric carcinoma tissues by immunohistochemistry using tissue array slides. In metastatic gastric carcinomas, the expressions of epidermal growth factor receptor, c-erbB2, and trefoil factor 1(TFF-1) were higher and those of beta-catenin, E-cadherin, fragile histone triad gene (FHIT), glutathione S transferase-pi (GST-pi), kangai 1 (KAI1), and nuclear factor-kappaB (NF-kappaB) were lower than in primary gastric carcinomas. Furthermore, the expressions of beta-catenin, E-cadherin, KAI1, and NF-kappaB were associated with an advanced T and combined stage. In addition, the loss of E-cadherin expression during lymph node metastasis or E-cadherin immunonegativity in metastatic lesions and epidermal growth factor receptor expression in primary gastric carcinomas were independently associated with a poor prognosis by multivariate analysis. In conclusion, the expression of some tumor-associated proteins and their prognostic significance in metastatic gastric carcinomas differ from those in primary tumors. Consequently, analysis of both metastatic gastric carcinomas and their primary counterparts may be required to fully determine the molecular characteristics of node-positive gastric carcinoma.

Role of the CXCR4/CXCL12 signaling axis in breast cancer metastasis to the brain

Breast cancer is the most common malignancy and second leading cause of cancer death in women. Ninety percent of mortality in breast cancer is often associated with metastatic progression or relapse in patients. Critical stages in the development of aggressive breast cancer include the growth of primary tumors and their ability to spread to foreign organs and form metastases, as well as the establishment of an independent blood supply within the new tumors. Hence, it is imperative to characterize the key molecules that regulate the metastasis of human breast cancer cells. The expression of CXCR4/CXCL12 in breast tumors has been correlated with a poor prognosis, increased metastasis, resistance to conventional therapeutic agents and a poor outcome in the pathogenesis of breast cancer. However, effective anti-CXCR4 therapy remains a challenge. Here, we will review the putative involvement of the CXCR4/CXCL12 signaling axis in breast cancer metastasis to the brain. Characterization of signaling events important for breast cancer cell growth and their metastasis to the brain should provide insights into breast cancer therapies and improved, successful treatments for breast cancer.

Epithelial mesenchymal transition traits in human breast cancer cell lines

Epithelial mesenchymal transition (EMT) has long been associated with breast cancer cell invasiveness and evidence of EMT processes in clinical samples is growing rapidly. Genome-wide transcriptional profiling of increasingly larger numbers of human breast cancer (HBC) cell lines have confirmed the existence of a subgroup of cell lines (termed Basal B/Mesenchymal) with enhanced invasive properties and a predominantly mesenchymal gene expression signature, distinct from subgroups with predominantly luminal (termed Luminal) or mixed basal/luminal (termed Basal A) features (Neve et al Cancer Cell 2006). Studies providing molecular and cellular analyses of EMT features in these cell lines are summarised, and the expression levels of EMT-associated factors in these cell lines are analysed. Recent clinical studies supporting the presence of EMT-like changes in vivo are summarised. Human breast cancer cell lines with mesenchymal properties continue to hold out the promise of directing us towards key mechanisms at play in the metastatic dissemination of breast cancer.