Biomarkers for the clinical management of breast cancer: international perspective

Recent developments in proteomic methods and disease biomarkers

Proteomic methodologies for identification and analysis of biomarkers have gained more attention during recent years and have evolved rapidly. Identification and detection of disease biomarkers are important to foresee outbreaks of certain diseases thereby avoiding surgery and other invasive and expensive medical treatments for patients. Thus, more research into discovering new biomarkers and new methods for faster and more accurate detection is needed. It is often difficult to detect and measure biomarkers because of their low concentrations and the complexity of their respective matrices. Therefore it is hard to find and validate methods for accurate screening methods suitable for clinical use. The most recent developments during the last three years and also some historical considerations of proteomic methodologies for identification and validation of disease biomarkers are presented in this review.

Does CSE1L Overexpression Affect Distant Metastasis Development in Breast Cancer?

BACKGROUND

CSE1L (chromosome segregation 1-like) is the human homologue to the yeast gene CSE1, and is related to invasion and metastasis in cancer progression. The aim of this study was to investigate the potential role of CSE1L expression in distant metastasis of breast cancer.

PATIENTS AND METHODS

A total of 71 breast cancer patients were included in this study. Clinical characteristics and CSE1L status were evaluated. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded archival breast tumor tissue. The results of CSE1L staining were analyzed according to the percentage of immunoreactive cells.

RESULTS

34 patients had distant metastasis and 37 did not. The mean age of the patients was 50.5 ± 12.1 years. Age, tumor size, and hormone receptor status were similar in patients with distant metastasis and in those without. A statistically significant relationship was found between nuclear CSE1L expression and distant metastasis of breast cancer. Lymph node metastasis and nuclear grade were other factors affecting distant metastasis.

CONCLUSION

There is a relationship between nuclear CSE1L overexpression and distant metastasis in breast cancer. CSE1L status may therefore become a valuable prognostic tool in the future.

Circulating DNA of HOTAIR in serum is a novel biomarker for breast cancer

Long non-coding HOX transcript antisense intergenic RNA (HOTAIR) plays an important role in breast cancer. The purpose of this study was to determine whether circulating HOTAIR can be used for breast cancer diagnosis. HOTAIR in serum was measured by PCR-based direct detection. Reverse transcriptase and DNase I treatment were used to distinguish the DNA and RNA forms of HOTAIR. To determine whether circulating HOTAIR is a biomarker for breast cancer, the DNA of HOTAIR from breast cancer patients and healthy controls was measured at both the discovery stage (48 individuals) and an independent validation stage (156 individuals). The diagnostic accuracy was assessed by the receiver operating characteristic curve (ROC) and the area under the curve (AUC). We showed that the major form of HOTAIR-derived fragment in serum is DNA rather than RNA in our study, the same as for MALAT-1, another well-described lincRNA. A higher circulating DNA level of HOTAIR was found in patients at the discovery stage (P = 0.0008). ROC analysis revealed that the circulating HOTAIR DNA distinguished breast cancer patients from healthy individuals (AUC = 0.799). This finding was confirmed at the validation stage. Though circulating MALAT-1 DNA was altered in the discovery stage, it showed no significant difference in the validation stage. In the entire set of 204 samples, the circulating HOTAIR DNA showed a 2.15-fold change in patients compared with healthy controls (P < 0.0001, AUC = 0.786). The optimal cutoff value for diagnosis was 0.30 with sensitivity of 80.0 % and specificity of 68.3 %. Moreover, a correlation between the DNA level of circulating HOTAIR and the progress of breast cancer was established. We have demonstrated that the circulating DNA of HOTAIR is a potential biomarker for breast cancer.

Could the Breast Prognostic Biomarker Status Change During Disease Progression? An Immunohistochemical Comparison between Primary Tumors and Synchronous Nodal Metastasis

BACKGROUND

Prognostic biomarkers in breast cancer are routinely investigated in the primary tumors to guide further management. However, it is proposed that the expression may change during the disease progression, and may result in a different immune profile in the metastatic nodes. This work aimed to investigate the expression of breast prognostic biomarkers in primary tumors and in its axillary nodal metastasis, to estimate the possible discordant expression.

MATERIALS AND METHODS

60 paired primary and axillary nodal metastasis samples were collected from patients with primary breast cancer with positive nodal deposits, diagnosed at the Maadi Military Hospital, Cairo, Egypt, during the year 2013. ER, PR and HER2 expression was assessed by immunohistochemistry in all samples

RESULTS

48.3% of the included cases showed concordant results for both ER and PR receptors between the primary tumor and its nodal metastasis while 51.7% showed discordant results and the discordance level was statistically significant. On the other hand, 70% of the cases showed concordant Her2 results between the primary tumors and the nodal deposits, 30% showed discordant results and the difference was significant.

CONCLUSIONS

The study indicated that the discordance in ER and PR receptor expression between the primary breast tumor and their nodal metastasis may be significant. The possible switch in the biomarker status during the disease progression is worth noting and may change the patient therapeutic planning. So, whether the treatment selection should be based on biomarkers in the lymph node is a topic for further studies and future clinical trials.

Estrogen receptor-α drives adiponectin effects on cyclin D1 expression in breast cancer cells

Obesity is a risk factor for breast cancer, largely due to altered expression of various adipocytokines. As it concerns adiponectin, there are not univocal results regarding its role in breast cancer occurrence and progression. Here, we demonstrate that in animals injected with human estrogen receptor (ER)-α-negative MDA-MB-231 cells pretreated with adiponectin (1 and 5 µg/ml), a significant reduction (60 and 40%, respectively) in tumor volume is observed, whereas an increased tumor growth (54 and 109%, respectively) is evidenced in the animals receiving human ER-α-positive MCF-7 cells. Moreover, cyclin D1 (CD1) mRNA and protein levels are decreased in MDA-MB-231 cells, whereas they are up-regulated in ER-α-positive cells by adiponectin. These findings fit with the opposite effects of adiponectin on CD1 promoter: 0.44- and 0.34-fold decrease in MDA-MB-231 cells and 0.63- and 0.95-fold increase in MCF-7 cells, treated with 1 and 5 µg/ml, respectively. Functional studies indicate that these effects are mediated by the specific protein 1 motif located in the CD1 promoter. In the absence of ER-α, the adiponectin-mediated down-regulation of CD1 involves the recruitment of corepressors. In the presence of ER-α, the adiponectin-induced expression of CD1 requires the involvement of an activator complex. In conclusion, we propose that a possible mechanism through which adiponectin differently affects breast cancer growth is the opposite modulation of CD1 levels accordingly to ER-α expression.

A kinetic model identifies phosphorylated estrogen receptor-α (ERα) as a critical regulator of ERα dynamics in breast cancer

Receptor levels are a key mechanism by which cells regulate their response to stimuli. The levels of estrogen receptor-α (ERα) impact breast cancer cell proliferation and are used to predict prognosis and sensitivity to endocrine therapy. Despite the clinical application of this information, it remains unclear how different cellular processes interact as a system to control ERα levels. To address this question, experimental results from the ERα-positive human breast cancer cell line (MCF-7) treated with 17-β-estradiol or vehicle control were used to develop a mass-action kinetic model of ERα regulation. Model analysis determined that RNA dynamics could be captured through phosphorylated ERα (pERα)-dependent feedback on transcription. Experimental analysis confirmed that pERα-S118 binds to the estrogen receptor-1 (ESR1) promoter, suggesting that pERα can feedback on ESR1 transcription. Protein dynamics required a separate mechanism in which the degradation rate for pERα was 8.3-fold higher than nonphosphorylated ERα. Using a model with both mechanisms, the root mean square error was 0.078. Sensitivity analysis of this combined model determined that while multiple mechanisms regulate ERα levels, pERα-dependent feedback elicited the strongest effect. Combined, our computational and experimental results identify phosphorylation of ERα as a critical decision point that coordinates the cellular circuitry to regulate ERα levels.

The prognostic value of phosphorylated Akt in breast cancer: a systematic review

The prognostic value of phosphorylated Akt (pAkt) overexpression in breast cancer has been investigated by many studies with inconsistent results. This systematic review was conducted to evaluate the association of pAkt overexpression with breast cancer prognosis in terms of overall survival and disease-free survival. Three electronic databases (PubMed, EMBASE and Chinese Biomedical Literature Database) were comprehensively searched. Hazard ratios (HRs) with 95% confidence intervals (CIs) from different studies were combined using the random-effects model. In total, 33 studies with 9,836 patients were included for final analysis. The summary HR for overall survival and disease-free survival was 1.52 (95% CI: 1.29-1.78) and 1.28 (95% CI: 1.13-1.45), respectively, indicating higher risk of death and disease recurrence associated with pAkt overexpression. The results were robust in sensitivity analyses by omitting one study each time and by using the fixed-effects model instead. Subgroup and meta-regression analyses did not show that the prognostic effect of pAkt overexpression would change materially with such factors as population, status of hormone receptors, hormonal or trastuzumab treatment given, analyzing method (univariate versus multivariate) and methodological quality of the original studies. In conclusion, the available evidence suggests that pAkt overexpression is an adverse prognostic factor for breast cancer.

Estrogen receptors β1 and β2 are associated with distinct responses of estrogen receptor α-positive breast carcinoma to adjuvant endocrine therapy

Our purpose was to assess whether and how ERβ1 and/or ERβ2 expression status could predict response of early stage ERα-positive breast carcinoma to adjuvant endocrine therapy (AET). ERβ1 and ERβ2 expression were determined using immunohistochemistry. ERβ1- and ERβ2-positivity were derived from receiver operating characteristic analysis and the median percentage of immunostained tumor cells, respectively. Patients with recurrent disease were grouped according to whether they relapsed within 4 years or after 4 years from surgery. The predictive significance of ERβ1 and ERβ2 was determined using Kaplan-Meier survival analysis and Cox proportional hazards regression analysis. ERβ1-positivity in the first-4-year relapse patient group was lower and ERβ2-positivity in the post-4-year relapse group was higher compared with no-relapse group. ERβ1-positivity was associated with lower tumor size and longer first-4-year disease-free survival, while ERβ2-positivity was associated with shorter post-4-year disease-free survival. Cox multivariate analysis including ERβ1, ERβ2 and established clinico-pathological variables showed that ERβ1-positivity was an independent predictor of lower first-4-year risk of relapse. Thus, low ERβ1 expression and high ERβ2 expression are markers for identification of AET-treated ERα-positive breast carcinoma patients at risk of early and late relapse, respectively.

The histone chaperone HJURP is a new independent prognostic marker for luminal A breast carcinoma

BACKGROUND

Breast cancer is a heterogeneous disease with different molecular subtypes that have varying responses to therapy. An ongoing challenge in breast cancer research is to distinguish high-risk patients from good prognosis patients. This is particularly difficult in the low-grade, ER-positive luminal A tumors, where robust diagnostic tools to aid clinical treatment decisions are lacking. Recent data implicating chromatin regulators in cancer initiation and progression offers a promising avenue to develop new tools to help guide clinical decisions.

METHODS

Here we exploit a published transcriptome dataset and an independent validation cohort to correlate the mRNA expression of selected chromatin regulators with respect to the four intrinsic breast cancer molecular subtypes. We then perform univariate and multivariate analyses to compare the prognostic value of a panel of chromatin regulators to Ki67, a currently utilized proliferation marker.

RESULTS

Unsupervised hierarchical clustering revealed a gene cluster containing several histone chaperones and histone variants highly-expressed in the proliferative subtypes (basal-like, HER2-positive, luminal B) but not in the luminal A subtype. Several chromatin regulators, including the histone chaperones CAF-1 (subunits p150 and p60), ASF1b, and HJURP, and the centromeric histone variant CENP-A, associated with local and metastatic relapse and poor patient outcome. Importantly, we find that HJURP can discriminate favorable and unfavorable outcome within the luminal A subtype, outperforming the currently utilized proliferation marker Ki67, as an independent prognostic marker for luminal A patients.

CONCLUSIONS

The integration of chromatin regulators as clinical biomarkers, in particular the histone chaperone HJURP, will help guide patient substratification and treatment options for low-risk luminal A breast carcinoma patients.

Breast carcinoma: molecular profiling and updates

The most significant contribution of molecular subtyping of breast carcinomas has been the identification of estrogen-positive and estrogen-negative tumor subtypes, which are 2 distinct entities with differing prognoses and requiring different therapy. Molecular and genetic analyses can provide prognostic information; however, a thorough histopathologic evaluation with an evaluation of predictive biomarkers will provide similar information. Knowledge of genetic alterations in these tumors will help identify novel therapeutic targets, which might have an impact on prognosis. Understanding the progression pathways involved in the transition of in situ carcinoma to invasive carcinoma might lead to efficient risk stratification in these patients.

Microfluidic platforms for biomarker analysis

Biomarkers have been described as characteristics, most often molecular, that provide information about biological states, whether normal, pathological, or therapeutically modified. They hold great potential to assist diagnosis and prognosis, monitor disease, and assess therapeutic effectiveness. While a few biomarkers are routinely utilised clinically, these only reflect a very small percentage of all biomarkers discovered. Numerous factors contribute to the slow uptake of these new biomarkers, with challenges faced throughout the biomarker development pipeline. Microfluidics offers two important opportunities to the field of biomarkers: firstly, it can address some of these developmental obstacles, and secondly, it can provide the precise and complex platform required to bridge the gap between biomarker research and the biomarker-based analytical device market. Indeed, adoption of microfluidics has provided a new avenue for advancement, promoting clinical utilisation of both biomarkers and their analytical platforms. This review will discuss biomarkers and outline microfluidic platforms developed for biomarker analysis.

Identification of estrogen receptor proteins in breast cancer cells using matrix-assisted laser desorption/ionization time of flight mass spectrometry (Review)

Estrogen receptors [ERs (subtypes α and β)], classified as a nuclear receptor super family, are intracellular proteins with an important biological role as the transcription factors for estrogen target genes. For ER-induced transcription, an interaction must exist between ligand and coregulators. Coregulators may stimulate (coactivators) or inhibit (corepressors) transcription, following binding with a specific region of the gene, called the estrogen response element. Misbalanced activity of coregulators or higher ligand concentrations may cause increased cell proliferation, resulting in specific types of cancer. These are exhibited as overexpression of ER proteins. Breast cancer currently ranks first in the incidence and second in the mortality of cancer in females worldwide. In addition, 70% of breast tumors are ERα positive and the importance of these proteins for diagnostic use is indisputable. Early diagnosis of the tumor and its classification has a large influence on the selection of appropriate therapy, as ER-positive tumors demonstrate a positive response to hormonal therapy. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS) has been hypothesized to have great potential, as it offers reliable, robust and efficient analysis methods for biomarker monitoring and identification. The present review discusses ER protein analysis by MALDI TOF MS, including the crucial step of protein separation.

Prognostic relevance of cancer-associated fibroblasts in human cancer

Prognostication is an integral part of cancer diagnostic and helps oncologists to guide treatment decisions and therapy intensity. Accumulating evidence suggest that the stroma compartment also contains independent prognostic information, best exemplified by the impact of immune cells and cells of the vasculature on cancer progression. Similarly, strong experimental evidence exist that stromal fibroblasts, often designated cancer associated fibroblasts (CAFs), are actively involved in tumorigenesis. Thus, it can be anticipated that the molecular repertoire of CAFs is likewise important for the clinical behavior of the tumor. In this review we present recent studies addressing the prognostic impact of CAFs, with the focus on human lung and breast cancer. Several single markers have been suggested, either CAF specific or CAF derived, that in immunohistochemical studies have demonstrated independent association with survival. This includes members of the platelet derived growth factor receptor (PDGFR) family, CAF-markers like podoplanin and fibroblast activation protein (FAP) as well as transcription factors (FoxF1) and secreted factors (matrix metalloproteinases (MMPs), SPARC). However, most studies are based on explorative evaluations on single patient cohorts and require further validation. Using a more comprehensive approach, microarray studies have been employed to create gene expression signatures that detect an activated fibroblast state. These "stroma signatures" have been applied to identify specific CAF features associated with prognosis in several independent data sets of breast and lung cancer patients. Early studies in breast cancer have also demonstrated that fibroblast features influence therapy response. Thus, many strategies have been used to present encouraging proof-of-concept findings that CAFs could be exploited for prognostication. However, these studies also highlight the difficulties to conclusively define an "activated stroma" and to identify the individual factors involved in clinically relevant tumor-stroma interactions.

Progression of luminal breast tumors is promoted by ménage à trois between the inflammatory cytokine TNFα and the hormonal and growth-supporting arms of the tumor microenvironment

Breast cancer progression is strongly linked to inflammatory processes, aggravating disease course. The impacts of the inflammatory cytokine TNFα on breast malignancy are not fully substantiated, and they may be affected by cooperativity between TNFα and other protumoral mediators. Here, we show that together with representatives of other important arms of the tumor microenvironment, estrogen (hormonal) and EGF (growth-supporting), TNFα potently induced metastasis-related properties and functions in luminal breast tumor cells, representing the most common type of breast cancer. Jointly, TNFα + Estrogen + EGF had a stronger effect on breast cancer cells than each element alone, leading to the following: (1) extensive cell spreading and formation of FAK/paxillin-enriched cellular protrusions; (2) elevated proportion of tumor cells coexpressing high levels of CD44 and β1 and VLA6; (3) EMT and cell migration; (4) resistance to chemotherapy; (5) release of protumoral factors (CXCL8, CCL2, MMPs). Importantly, the tumor cells used in this study are known to be nonmetastatic under all conditions; nevertheless, they have acquired high metastasizing abilities in vivo in mice, following a brief stimulation by TNFα + Estrogen + EGF. These dramatic findings indicate that TNFα can turn into a strong prometastatic factor, suggesting a paradigm shift in which clinically approved inhibitors of TNFα would be applied in breast cancer therapy.

The expression and clinical significance of HERC4 in breast cancer

Background

Increasing evidence suggest that ubiquitin-proteasome system (UPS) plays a key role in tumorigenesis. HERC4 is a recently identified ubiqutin ligase. However, the expression status and biological functions of HERC4 in cancers are not clearly.

Methods

We evaluated the HERC4 expression in breast cancer cell lines and breast tumor tissues by quantitative real-time PCR and western blot analysis. To investigate the clinicopathological significance of HERC4, immunohistochemistry analysis for HERC4 was performed on a tissue microarray including 13 benign fibroadenoma, 15 intraductal carcinoma, 120 histologically confirmed invasive ductal carcinoma. Receiver operating characteristic (ROC) analysis was applied to determine the optimal cut-off score for positive expression of HERC4, when HERC4 positive expression percentage was above 60%, tumor was defined as “positive”.

Results

HERC4 was up-regulated in breast cancer cell lines and breast tumor tissues compared to non-tumorigenic cell line and adjacent normal breast tissues. According to ROC analysis, HERC4 positive expression was detected in 1/16 (6.3%) of normal breast tissue, in 3/13 (23.1%) of fibroadenoma, in 6/15 (40%) of intraductal carcinoma and 66/120 (55%) of invasive ductal carcinoma. Positive expression of HERC4 was positively correlated with pT status, pN status, clinical stage and histological grade of patients with invasive ductal carcinoma (p < 0.05).

Conclusions

Our findings suggest that HERC4 was a significant diagnostic marker for invasive ductal carcinoma of the breast.

Molecular and protein markers for clinical decision making in breast cancer: today and tomorrow

In early breast cancer (eBC), established clinicopathological factors are not sufficient for clinical decision making particularly regarding adjuvant chemotherapy since substantial over- or undertreatment may occur. Thus, novel protein- and molecular markers have been put forward as decision aids. Since these potential prognosis and/or predictive tests differ substantially regarding their methodology, analytical and clinical validation, this review attempts to summarize the essential facts for clinicians. This review focuses on those markers which are the most advanced so far in their development towards routine clinical application, i.e. two protein markers (i.e. uPA/PAI-1 and IHC4) and six molecular multigene tests (i.e. Mammaprint®, Oncotype DX®, PAM50, Endopredict®, the 97-gene genomic grade, and 76 gene Rotterdam signatures). Next to methodological aspects, we summarized the clinical evidences, in particular the main prospective clinical trials which have already been fully recruited (i.e. MINDACT, TAILORx, WSG PLAN B) or are still ongoing (i.e. RxPONDER/SWOG S1007, WSG-ADAPT). Last but not least, this review points out the key elements for clinicians to select one test among the wide panel of proposed assays, for a specific population of patients in term of level of evidence, analytical and clinical validity as well as cost effectiveness.

Vitamin D receptor gene ApaI polymorphism and breast cancer susceptibility: a meta-analysis

Vitamin D receptor (VDR) principally mediates the anticancer activities of vitamin D. Many studies investigated the association between VDR gene ApaI polymorphism and breast cancer, but the results were inconclusive. We performed this meta-analysis to evaluate the association between VDR gene ApaI polymorphism and breast cancer. Twelve studies with a total of 8,254 subjects were identified from PubMed and Wanfang databases. The pooled odds ratio (OR) and confidence intervals (95% CI) were used to assess the association. The meta-analysis indicated that VDR gene ApaI polymorphism was not associated with risk of breast cancer (a vs. A: OR = 0.97, 95% CI 0.91-1.04, P = 0.378; aa vs. AA: OR = 0.97, 95% CI 0.85-1.10, P = 0.618; aa vs. AA + Aa: OR = 1.00, 95% CI 0.89-1.12, P = 0.972; aa + Aa vs. AA: OR = 0.95, 95% CI 0.82-1.11, P = 0.550). Subgroup analysis by ethnicity further showed that VDR gene ApaI polymorphism was not associated with risk of breast cancer in both Asians and Caucasians. These data from the meta-analysis indicate that VDR gene ApaI polymorphism is not associated with breast cancer susceptibility.

Oleuropein and hydroxytyrosol activate GPER/ GPR30-dependent pathways leading to apoptosis of ER-negative SKBR3 breast cancer cells

SCOPE

We have previously demonstrated that oleuropein (OL) and hydroxytyrosol (HT) reduce 17β-estradiol-mediated proliferation in MCF-7 breast cancer (BC) cells without affecting the classical genomic action of estrogen receptor (ER), but activating instead the ERK1/2 pathway. Here, we hypothesized that this inhibition could be mediated by a G-protein-coupled receptor named GPER/GPR30. Using the ER-negative and GPER-positive SKBR3 BC cells as experimental model, we investigated the effects of OL and HT on GPER-mediated activation of downstream pathways.

METHODS AND RESULTS

Docking simulations and ligand-binding studies evidenced that OL and HT are able to bind GPER. MTT cell proliferation assays revealed that both phenols reduced SKBR3 cell growth; this effect was abolished silencing GPER. Focusing on OL and HT GPER-mediated pathways, using Western blot analysis we showed a sustained ERK1/2 activation triggering an intrinsic apoptotic pathway.

CONCLUSION

Showing that OL and HT work as GPER inverse agonists in ER-negative and GPER-positive SKBR3 BC cells, we provide novel insights into the potential of these two molecules as tools in the therapy of this subtype of BC.

Modeling the estrogen receptor to growth factor receptor signaling switch in human breast cancer cells

Breast cancer cells develop resistance to endocrine therapies by shifting between estrogen receptor (ER)-regulated and growth factor receptor (GFR)-regulated survival signaling pathways. To study this switch, we propose a mathematical model of crosstalk between these pathways. The model explains why MCF7 sub-clones transfected with HER2 or EGFR show three GFR-distribution patterns, and why the bimodal distribution pattern can be reversibly modulated by estrogen. The model illustrates how transient overexpression of ER activates GFR signaling and promotes estrogen-independent growth. Understanding this survival-signaling switch can help in the design of future therapies to overcome resistance in breast cancer.

Molecular and cellular heterogeneity in breast cancer: challenges for personalized medicine

Breast cancer is noted for disparate clinical behaviors and patient outcomes, despite common histopathological features at diagnosis. Molecular pathogenesis studies suggest that breast cancer is a collection of diseases with variable molecular underpinnings that modulate therapeutic responses, disease-free intervals, and long-term survival. Traditional therapeutic strategies for individual patients are guided by the expression status of the estrogen and progesterone receptors (ER and PR) and human epidermal growth factor receptor 2 (HER2). Although such methods for clinical classification have utility in selection of targeted therapies, short-term patient responses and long-term survival remain difficult to predict. Molecular signatures of breast cancer based on complex gene expression patterns have utility in prediction of long-term patient outcomes, but are not yet used for guiding therapy. Examination of the correspondence between these methods for breast cancer classification reveals a lack of agreement affecting a significant percentage of cases. To realize true personalized breast cancer therapy, a more complete analysis and evaluation of the molecular characteristics of the disease in the individual patient is required, together with an understanding of the contributions of specific genetic and epigenetic alterations (and their combinations) to management of the patient. Here, we discuss the molecular and cellular heterogeneity of breast cancer, the impact of this heterogeneity on practical breast cancer classification, and the challenges for personalized breast cancer treatment.

Angiogenic markers: molecular targets for personalized medicine in pituitary adenoma

AIM

Pituitary adenomas are typically slow-growing and histologically benign tumors that can occasionally behave in a malignant-like manner, invading adjacent structures or recurring after treatment. Using protein analysis methods and multiplex xMAP assays, we aimed to find out if these particular types of tumors express angiogenic markers VEGF and basic FGF (bFGF), which are associated with tumor growth and invasiveness, and quantify them in order to establish their usefulness as biomarkers.

MATERIALS & METHODS

We have analysed the expression of angiogenic markers VEGF and bFGF in serum and tissue specimens from 66 pituitary adenomas (43 invasive and 23 noninvasive). For serum analysis, we used xMAP and ELISA, and for tissue analysis, we performed histopathology and immunohistochemistry.

RESULTS & CONCLUSION

We measured the serum angiogenic factors in pituitary adenomas. The quantification methods revealed significant differences between pituitary adenoma patients and controls, for both VEGF (212.4 vs 112.5 pg/ml in controls) and bFGF (mean value of 12.6 vs 10.8 pg/ml in controls), and also differentiated between invasive and noninvasive adenomas (p < 0.05). The tissue expression of VEGF and bFGF strongly correlated with their serum level increase. Our findings can be further developed into methods for selection of patients suitable for personalized, antiangiogenic therapy.

Prognostic value of phosphorylated HER2 in HER2-positive breast cancer patients treated with adjuvant trastuzumab

BACKGROUND

Adjuvant trastuzumab has been routinely used in HER2-positive operable breast cancer patients. Prognostic factors remain to be well characterized in these patients and might correlate with primary and/or acquired resistance to trastuzumab.

PATIENTS AND METHODS

The study subjects were 78 HER2-positive operable breast cancer patients treated with adjuvant chemotherapy followed by 1-year trastuzumab between 2005 and 2010 in our institute. All breast tumors showed a HercepTest score of 3+ or that of 2+ and positive fluorescence in situ hybridization. Expression levels of HER1, phosphorylated HER2 (pY1248), HER3, HER4, and p53 were assessed by immunohistochemistry. Prognostic factors were investigated with univariate and multivariate analyses using the Kaplan-Meier/log-rank test and Cox proportional hazards model, respectively.

RESULTS

The median age and follow-up period of the patients were 54 years and 39 months, respectively. The mean tumor size was 2.1 cm and the node-positive rate was 42 %. Eight patients had recurrent diseases but no patient died of cancer. Univariate analysis revealed that pHER2 positivity was only a significantly worse prognostic factor for relapse-free survival (RFS) (P = 0.049). A HercepTest score of 2+ and high expression level of p53 showed a trend. Multivariate analysis revealed three biological markers: pHER2 positivity [hazard ratio (HR) = 11.6, 95 % confidence interval (CI) 1.3-111.1, P = 0.031], p53 positivity (HR = 6.4, 95 % CI 1.0-40.0, P = 0.047) and a HercepTest score of 2+ (HR = 8.6, 95 % CI 1.6-45.2, P = 0.011) to be worse prognostic factors for RFS. Notably, three out of five patients with breast tumors expressing HER2 at a score of 2+ and pHER2 had recurrent diseases. Interestingly, the expression level of pHER2 significantly correlated with the expression levels of HER2 and HER3 in HER2-positive breast tumors.

CONCLUSIONS

This retrospective cohort study suggests that a lower expression level of HER2 and high expression levels of pHER2 and p53 may indicate a worse prognosis in HER2-positive breast cancer patients treated with trastuzumab and chemotherapy. Further studies are needed to evaluate pHER2 expression in HER2-positive breast cancer as a prognostic and/or predictive marker.

A checklist for ascertaining study cohorts in oncology health services research using secondary data: report of the ISPOR oncology good outcomes research practices working group

OBJECTIVES

The ISPOR Oncology Special Interest Group formed a working group at the end of 2010 to develop standards for conducting oncology health services research using secondary data. The first mission of the group was to develop a checklist focused on issues specific to selection of a sample of oncology patients using a secondary data source.

METHODS

A systematic review of the published literature from 2006 to 2010 was conducted to characterize the use of secondary data sources in oncology and inform the leadership of the working group prior to the construction of the checklist. A draft checklist was subsequently presented to the ISPOR membership in 2011 with subsequent feedback from the larger Oncology Special Interest Group also incorporated into the final checklist.

RESULTS

The checklist includes six elements: identification of the cancer to be studied, selection of an appropriate data source, evaluation of the applicability of published algorithms, development of custom algorithms (if needed), validation of the custom algorithm, and reporting and discussions of the ascertainment criteria. The checklist was intended to be applicable to various types of secondary data sources, including cancer registries, claims databases, electronic medical records, and others.

CONCLUSIONS

This checklist makes two important contributions to oncology health services research. First, it can assist decision makers and reviewers in evaluating the quality of studies using secondary data. Second, it highlights methodological issues to be considered when researchers are constructing a study cohort from a secondary data source.