HER-3 Status by Immunohistochemistry in HER-2-Positive Metastatic Breast Cancer Patients Treated with Trastuzumab: Correlation with Clinical Outcome

Aims and Background

HER-3 signaling might contribute to resistance to trastuzumab. To clarify the role of HER-3 in HER-2-positive breast cancer, it is important to evaluate the level of HER-3 and its correlations with clinical outcome in metastatic breast cancer patients treated with trastuzumab.

Methods

HER-3 status by immunohistochemistry was evaluated in HER-2-positive metastatic breast cancer patients treated with trastuzumab-based therapy at our institution. Two scorings were utilized for interpreting staining for HER-3, and the correlation between HER-3 status and clinical outcome was evaluated.

Results

We evaluated HER-3 status in 61 of 76 HER-2-positive metastatic breast cancers treated with trastuzumab-based therapy at our institution from 4/1999 to 3/2006. We observed 55.2% objective responses; median time to progression and overall survival from start of trastuzumab therapy were 9.6 months (0.921–78.87) and 29.1 months (1.4–129.5+), respectively. With a cutoff of 50% staining tumor cells, we found 30 HER-3-negative and 31 HER-3-positive tumors. HER-3 status was not significantly associated with clinical outcome, but a shorter time to progression and overall survival were observed in patients with HER-3-positive tumors.

Conclusions

HER-3 status by immunohistochemistry was not significantly associated with clinical outcome in HER-2-positive metastatic breast cancer patients. Further studies are necessary to evaluate the prognostic and predictive role of HER-3.

Identification of increased NBS1 expression as a prognostic marker of squamous cell carcinoma of the oral cavity

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide; however, accurate molecular markers to predict its prognosis are still limited. We previously demonstrated that overexpression of the DNA double-strand break repair protein NBS1 is a prognostic marker of advanced head and neck squamous cell carcinoma (HNSCC). Therefore, we aimed to investigate the feasibility of using NBS1 as a biomarker in OSCC. In this study, we enrolled 148 OSCC for immunohistochemical (IHC) and clinical analysis. Data from 58 advanced non-oral-cavity HNSCC (NO-HNSCC) cases were also included for comparison due to the biological and clinical discrepancy between OSCC and HNSCC originated from the other sites (e.g. pharynx or larynx). First, we validated the NBS1 IHC results by real-time RT-PCR analysis, and an excellent correlation between the results of these two assays confirmed the reliability and robustness of IHC procedures and interpretation. NBS1 overexpression was an independent prognostic marker in both OSCC and NO-HNSCC cases. In OSCC, the prognostic significance of NBS1 was shown regardless of T stage and lymph node status. Increased NBS1 expression correlated with advanced T stage and recurrence/metastasis. NBS1 overexpression correlated with the phosphorylation levels of Akt and its downstream target mammalian target of rapamycin (mTOR). These results clearly illustrate the expression profile of NBS1 in OSCC and NO-HNSCC, and highlight the role of NBS1 in HNSCC irrespective of the primary sites. It also indicates the practicability of application of NBS1 as a marker in OSCC.

Evaluation of estrogen receptor alpha and beta and progesterone receptor expression and correlation with clinicopathologic factors and proliferative marker Ki-67 in breast cancers

To elucidate the molecular profile of hormonal steroid receptor status, we analyzed ER-alpha, ER-beta, and PGR mRNA and protein expression in 80 breast carcinomas using reverse transcriptase polymerase chain reaction (RT-PCR), quantitative RT-PCR, and immunohistochemical analysis. Qualitative analysis revealed positive expression of ER-alpha, ER-beta, and PGR mRNA in 48%, 59%, and 48% of the breast carcinomas, respectively. ER-alpha, ER-beta, and PGR transcript overexpression was observed in 51%, 0%, and 12% of the cases, respectively, whereas moderate or strong protein expression was detected in 68%, 78%, and 49% of the cases, respectively. Tumor grade was negatively correlated with transcript and protein levels of ER-alpha (P = .0169 and P = .0006, respectively) and PGR (P = .0034 and P = .0005, respectively). Similarly, proliferative index Ki-67 was negatively associated with transcript and protein levels of ER-alpha (P = .0006 and P < .0001, respectively) and PGR (P = .0258 and P = .0005, respectively). These findings suggest that ER-alpha and PGR expression are associated with well-differentiated breast tumors and less directly related to cell proliferation. A significant statistical difference was observed between lymph node status and ER-beta protein expression (P = .0208). In ER-alpha-negative tumors, we detected a correlation between ER-beta protein expression and high levels of Ki-67. These data suggest that ER-beta could be a prognostic marker in human breast cancer.

Conventional and new emerging prognostic factors in breast cancer: an update

This article reviews the conventional clinicopathological, as well as the principal new emerging prognostic factors of breast cancer and proposes a tumor marker utility grading system for their use. In spite of the many advances in molecular biology toward better defining the biological aggressiveness of the primary malignancy, the conventional node-negative status, tumor size and grade are still the strongest predictors of relapse-free survival and/or overall survival. Microvessel count and bone-marrow micrometastases, among the more recently studied clinicopathological prognostic factors, and amplification and/or p53 mutation and S-phase fraction among the biological ones must be considered investigational, although, with enough documentation recommending their usefulness. Estrogen and/or progesterone expression, c-erbB-2 amplification and/or mutation are the prognostic factors currently included in the principal clinical guidelines. They also enable probable forecast of the response to endocrine treatment or chemotherapy. In particular, c-erbB-2 is used to define the different risk categories of node-negative operated breast cancer patients. In recent years, microarray and quantitative reverse-transcription PCR technologies have enabled the study of multiple genetic alterations and computer algorithms have been developed for visual recognition of tumors that share so-called ‘signatures’. So far, different gene-expression patterns with different prognoses have been identified but methodological problems remain to be solved prior to routine use.

Comparative evaluation of non-informative HER-2 immunoreactions (2+) in breast carcinomas with FISH, CISH and QRT-PCR

The routine assessment of HER-2 expression can be affected by many immunohistological preanalytical and analytical variables. The evaluation of non-informative HER-2 tests, because of 2(+) scores, has been addressed in studies using in situ hybridization (fluorescent in situ hybridization (FISH) or chromogenic in situ hybridization (CISH)). There are very few studies that additionally checked 2(+) cases by quantitative reverse transcription-PCR (QRT-PCR). We analyzed totally 195 breast carcinoma cases, 70 of them showing 2(+) immunoreaction, with FISH/CISH and QRT-PCR. Confirmed amplification in 2(+) cases fell within the reported range (12.8% vs. 8-44%) and some of them showed lower mRNA levels indicating a genuine decrease of HER-2 protein as a mechanism for the non-informative score. In other cases, increased mRNA levels could be ascribed to HER-2 polysomy, verifying previous observations of immunohistologically detectable HER-2 polysomy. A remarkable subset of the 2(+) cases showed "normal" mRNA levels without amplification or polysomy and technical parameters as well as heterogeneity could be incriminated. The overall concordance of QRT-PCR and FISH was 93.8%, highest than most previously reported. Yet, the lack of clear cut-off mRNA values and the challenge of sample microdissection hinder QRT-PCR from claiming the status of a gold standard test for HER-2 evaluation.

Low E2F1 transcript levels are a strong determinant of favorable breast cancer outcome

Introduction

We investigated whether mRNA levels of E2F1, a key transcription factor involved in proliferation, differentiation and apoptosis, could be used as a surrogate marker for the determination of breast cancer outcome.

Methods

E2F1 and other proliferation markers were measured by quantitative RT-PCR in 317 primary breast cancer patients from the Stiftung Tumorbank Basel. Correlations to one another as well as to the estrogen receptor and ERBB2 status and clinical outcome were investigated. Results were validated and further compared with expression-based prognostic profiles using The Netherlands Cancer Institute microarray data set reported by Fan and colleagues.

Results

E2F1 mRNA expression levels correlated strongly with the expression of other proliferation markers, and low values were mainly found in estrogen receptor-positive and ERBB2-negative phenotypes. Patients with low E2F1-expressing tumors were associated with favorable outcome (hazard ratio = 4.3 (95% confidence interval = 1.8–9.9), P = 0.001). These results were consistent in univariate and multivariate Cox analyses, and were successfully validated in The Netherlands Cancer Institute data set. Furthermore, E2F1 expression levels correlated well with the 70-gene signature displaying the ability of selecting a common subset of patients at good prognosis. Breast cancer patients' outcome was comparably predictable by E2F1 levels, by the 70-gene signature, by the intrinsic subtype gene classification, by the wound response signature and by the recurrence score.

Conclusion

Assessment of E2F1 at the mRNA level in primary breast cancer is a strong determinant of breast cancer patient outcome. E2F1 expression identified patients at low risk of metastasis irrespective of the estrogen receptor and ERBB2 status, and demonstrated similar prognostic performance to different gene expression-based predictors.

Comparison of gene expression profiles in core biopsies and corresponding surgical breast cancer samples

Introduction

Gene expression profiling has been successfully used to classify breast cancer into clinically distinct subtypes, and to predict the risk of recurrence and treatment response. The aim of this study was to investigate whether the gene expression profile (GEP) detected in a core biopsy (CB) is representative for the entire tumor, since CB is an important tool in breast cancer diagnosis. Moreover, we investigated whether performing CBs prior to the surgical excision could influence the GEP of the respective tumor.

Methods

We quantified the RNA expression of 60 relevant genes by quantitative real-time PCR in paired CBs and surgical specimens from 22 untreated primary breast cancer patients. Subsequently, expression data were compared with independent GEPs obtained from tumors of 317 patients without preceding CB.

Results

In 82% of the cases the GEP detected in the CB correlated very well with the corresponding profile in the surgical sample (r_s ≥ 0.95, p < 0.001). Gene-by-gene analysis revealed four genes significantly elevated in the surgical sample compared to the CB; these comprised genes mainly involved in inflammation and the wound repair process as well as in tumor invasion and metastasis.

Conclusion

A GEP detected in a CB are representative for the entire tumor and is, therefore, of clinical relevance. The observed alterations of individual genes after performance of CB deserve attention since they might impact the clinical interpretation with respect to prognosis and therapy prediction of the GEP as detected in the surgical specimen following CB performance.

Increased Expression of Urokinase-Type Plasminogen Activator mRNA Determines Adverse Prognosis in ErbB2-Positive Primary Breast Cancer

Purpose

To evaluate and validate mRNA expression markers capable of identifying patients with ErbB2-positive breast cancer associated with distant metastasis and reduced survival.

Patients and Methods

Expression of 60 genes involved in breast cancer biology was assessed by quantitative real-time PCR (qrt-PCR) in 317 primary breast cancer patients and correlated with clinical outcome data. Results were validated subsequently using two previously published and publicly available microarray data sets with different patient populations comprising 295 and 286 breast cancer samples, respectively.

Results

Of the 60 genes measured by qrt-PCR, urokinase-type plasminogen activator (uPA or PLAU) mRNA expression was the most significant marker associated with distant metastasis-free survival (MFS) by univariate Cox analysis in patients with ErbB2-positive tumors and an independent factor in multivariate analysis. Subsequent validation in two microarray data sets confirmed the prognostic value of uPA in ErbB2-positive tumors by both univariate and multivariate analysis. uPA mRNA expression was not significantly associated with MFS in ErbB2-negative tumors. Kaplan-Meier analysis showed in all three study populations that patients with ErbB2-positive/uPA–positive tumors exhibited significantly reduced MFS (hazard ratios [HR], 4.3; 95% CI, 1.6 to 11.8; HR, 2.7; 95% CI, 1.2 to 6.2; and, HR, 2.8; 95% CI, 1.1 to 7.1; all P < .02) as compared with the group with ErbB2-positive/uPA–negative tumors who exhibited similar outcome to those with ErbB2-negative tumors, irrespective of uPA status.

Conclusion

After evaluation of 898 breast cancer patients, uPA mRNA expression emerged as a powerful prognostic indicator in ErbB2-positive tumors. These results were consistent among three independent study populations assayed by different techniques, including qrt-PCR and two microarray platforms.