c-erbB-2 protein overexpression in breast cancer is a risk factor in patients with involved and uninvolved lymph nodes

Surgical Management of the Axilla of HER2+ Breast Cancer in the Z1071 Era: A Propensity-Score-Matched Analysis of the NCDB

INTRODUCTION

We aim to analyze survival outcomes for sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND) in human epidermal growth factor receptor (HER2)+ infiltrative ductal carcinoma (IDC) that demonstrate complete clinical response (cCR) to neoadjuvant systemic therapy (NAST) after initial presentation with clinical N1 (cN1) disease.

METHODS

NCDB 2004-2017 was utilized for the analysis. Female patients with unilateral HER2+ IDC, stage cT1-T4 cN1, who demonstrated cCR to NAST with reported definitive axillary surgical management were included. Patients were propensity score matched, and overall survival (OS) was compared. Cox regression analysis was used to identify survival predictors.

RESULTS

6453 patients were selected, of whom 2461 (38.1%) had SLNB and 3992 (69.1%) had ALND as definitive axillary surgical management. The trend of SLNB utilization increased from 20% in 2012 to 50% in 2017. A total of 2454 patients were matched from each group with adequate adjustment for all variables. There was no difference in OS between SLNB versus ALND (84.03 ± 0.36 versus 84.62 ± 0.42 months; p = 0.522). Cox regression identified age, cT stage, primary tumor response to NAST, ypN+, and endocrine therapy as significant OS predictors. In subgroup analysis of patients with ypN+ who had SLNB as a definitive procedure, primary tumor response to NAST and continuation of adjuvant chemotherapy were associated with improved OS.

CONCLUSION

In cN1 HER2+ IDC patients who demonstrate cCR to NAST, SLNB is a reasonable definitive procedure for axillary management with comparable OS outcomes to ALND. However, higher-level data are required to determine the appropriate management in the case of ypN+.

HER2 expression on tumor-derived extracellular vesicles and circulating tumor cells in metastatic breast cancer

Background

Tumor-derived extracellular vesicles (tdEVs) and circulating tumor cells (CTCs) in the blood of metastatic cancer patients associate with poor outcomes. In this study, we explored the human epidermal growth factor receptor 2 (HER2) expression on CTCs and tdEVs of metastatic breast cancer patients.

Methods

Blood samples from 98 patients (CLCC-IC-2006-04 study) were originally processed with the CellSearch® system using the CTC kit and anti-HER2 as an additional marker in the staining cocktail. CTCs and tdEVs were automatically enumerated from the generated CellSearch images using the open-source ACCEPT software.

Results

CTCs and tdEVs were subdivided based on their cytokeratin (CK) and HER2 phenotype into CK+HER2−, CK−HER2+, and CK+HER2+. The inclusion of anti-HER2 increased the percentage of informative samples with ≥ 1 detectable CTC from 89 to 95%. CK− CTCs and tdEVs correlated equally well with the clinical outcome as CK+ CTCs and tdEVs. Inter- and intra-patient heterogeneity was found for the CTC/tdEV phenotypes, and the presence of 2 or 3 classes of CTCs/tdEVs was associated with worse prognosis compared to a uniform CTC/tdEV phenotype present (1 class). The use of ≥ 7% HER2+CK+ tdEVs can predict HER2 expression of the tissue with 74% sensitivity and specificity using the HER2 amplification status of the primary tumor as a classification variable.

Conclusions

HER2 can be detected on CTCs and tdEVs not expressing CK, and these CK− CTCs/tdEVs have similar clinical relevance to CTCs and tdEVs expressing CK. tdEVs perform better than CTCs in predicting the HER2 status of the primary tissue. CTC and tdEV heterogeneity in the blood of patients is inversely associated with overall survival.

Preliminary study on oncogene product immunohistochemistry (c-erbB-2, c-myc, ras p21, EGFR) in breast pathology

The expression of oncogene products related to cell growth (c-erbB-2, c-myc, ras p21, EGFR) was investigated in benign (15 cases) and malignant breast lesions (20 cases) by means of immunohistochemistry using the avidin-biotin-peroxidase technique with polyclonal and monoclonal antibodies. The aim of this study was to evaluate the relationship between the staining positivity and various morphological and biological features, such as tumour type, grading, hormone receptor status and cell kinetic parameters.

In benign breast lesions, as expected, the kinetic parameters were low, both for Ki-67 and LI. All the specimens showed a diploid condition (the DI being equal to 1) and we found a limited degree of immunoreactivity for all the growth factors and oncogene products. In breast cancer we studied the distribution of immunohistochemical positivity for EGFR, c-erbB-2, c-myc, ras p21 and Ki-67, which was related to age, nodal status, ER and PgR receptor status, LI, DI and histopathological grading. A significant positive correlation was found both between ras p21 espression and nodal status and ERICA positivity. We observed a strong correlation between LI and Ki-67 and an inverse relation between Ki-67 and ER expression. These findings suggest the importance of studying the relationship between prognostic factors which may provide preoperative prediction in the biological behaviour of breast cancer, not only on biopsy specimens, but also on fine needle aspirates.

Risk factors associated with the incidence and time to onset of lapatinib-induced hepatotoxicity

PURPOSE

Although lapatinib-induced hepatotoxicity can cause severe clinical complications in patients, the factors affecting hepatotoxicity have rarely been investigated. The purpose of this study was to investigate risk factors for hepatotoxicity and time to lapatinib-induced hepatotoxicity.

METHODS

This retrospective study was performed on metastatic breast cancer patients treated with lapatinib. Various factors were evaluated for hepatotoxicity and time to hepatotoxicity, including sex, age, body weight, height, body surface area, underlying disease, smoking history, start dose of lapatinib, status of liver metastasis, and concomitant drugs.

RESULTS

Among 159 patients, the percentage of patients with hepatotoxicity after lapatinib initiation was 57.9% (n = 92). Multivariate analysis showed that concomitant use of H2 blockers increased the incidence of hepatotoxicity by 2.3-fold. Patients who received CYP3A4 inducers had 3.1 times higher risk of hepatotoxicity incidence; the attributable risks of H2 blockers and CYP3A4 inducers were 56.7% and 68.1%, respectively. Use of H2 blockers increased the hazard of time to hepatotoxicity by 1.8-fold compared to non-use of H2 blockers.

CONCLUSIONS

Our study demonstrated that concomitant use of H2 blockers and CYP3A4 inducers was associated with lapatinib-induced hepatotoxicity. Close liver function monitoring is recommended, especially in patients receiving H2 blockers or CYP3A4 inducers.

Gene Expression Meta-Analysis of Potential Metastatic Breast Cancer Markers

Background:

Breast cancer metastasis is a highly prevalent cause of death for European females. DNA microarray analysis has established that primary tumors, which remain localized, differ in gene expression from those that metastasize. Cross-analysis of these studies allow to revile the differences that may be used as predictive in the disease prognosis and therapy.

Objective:

The aim of the project was to validate suggested prognostic and therapeutic markers using meta-analysis of data on gene expression in metastatic and primary breast cancer tumors.

Method:

Data on relative gene expression values from 12 studies on primary breast cancer and breast cancer metastasis were retrieved from Genevestigator (Nebion) database. The results of the data meta-analysis were compared with results of literature mining for suggested metastatic breast cancer markers and vectors and consistency of their reported differential expression.

Results:

Our analysis suggested that transcriptional expression of the COX2 gene is significantly downregulated in metastatic tissue compared to normal breast tissue, but is not downregulated in primary tumors compared with normal breast tissue and may be used as a differential marker in metastatic breast cancer diagnostics. RRM2 gene expression decreases in metastases when compared to primary breast cancer and could be suggested as a marker to trace breast cancer evolution. Our study also supports MMP1, VCAM1, FZD3, VEGFC, FOXM1 and MUC1 as breast cancer onset markers, as these genes demonstrate significant differential expression in breast neoplasms compared with normal breast tissue.

Conclusion:

COX2 and RRM2 are suggested to be prominent markers for breast cancer metastasis. The crosstalk between upstream regulators of genes differentially expressed in primary breast tumors and metastasis also suggests pathways involving p53, ER1, ERB-B2, TNF and WNT, as the most promising regulators that may be considered for new complex drug therapeutic interventions in breast cancer metastatic progression.

Mutual Predictive Value of c-erbB-2 Overexpression and Various Prognostic Factors in Ductal Invasive Breast Carcinoma

AIMS AND BACKGROUND

Breast carcinoma is a heterogeneous disease, the prognosis of which correlates with various prognostic factors. The aim of this study was to assess the prognostic significance of c-erbB-2 overexpression in breast carcinoma patients in association with other known prognostic factors.

METHODS & STUDY DESIGN

The relationship between immunohistochemical expression of the c-erbB-2 oncoprotein and various established prognostic factors such as tumor size, axillary node status, estrogen and progesterone receptor status, DNA ploidy, proliferation index, cathepsin D expression and histological grade in invasive ductal breast carcinoma is presented in this study.

RESULTS

Of the 93 ductal invasive carcinomas 22 (23.7%) were grade I, 51 (54.8%) grade II, and 20 (21.5%) grade III, and the majority (78: 83.9%) were 2-5 cm in diameter. Tumor metastases were identified in one or more lymph nodes in 55 (59.1%) patients, the remaining 38 (40.9%) patients being lymph node negative. According to the DNA histograms 40 (43.0%) tumors were aneuploid and 53 (57.0%) were diploid, and the majority of tumors had more than 4% of cells in the S phase of the cell cycle (83.9%). Expression of c-erbB-2 as shown by immunohistochemical intense membrane staining was present in 49 (52.7%) tumors. Cathepsin D-positive cytoplasmic granular staining and cathepsin D-positive stromal macrophages were found in 60 (64.5%) and 72 (77.4%) tumors, respectively. Univariate analysis showed that overall survival correlated significantly with axillary lymph node involvement and with estrogen and progesterone receptor status for each of the receptors separately and for their coexpression, and only marginally with c-erbB-2 overexpression. In mulitivariate analysis only axillary lymph node metastases and coexpression of estrogen and progesterone receptors were found to be independent and significant prognostic factors.

CONCLUSIONS

When patients were stratified according to c-erbB-2 expression it was shown that those with c-erbB-2 overexpression and grade II tumors, tumor size greater than 2 cm, high content of aneuploid cells and cathepsin D-positive stromal macrophages had a shorter long-term survival than c-erbB-2 negative patients.

C-erbB-2 Expression in Primary Breast Cancer

c-erbB-2 is an oncoprotein which is overexpressed in up to 40% of primary breast cancers. c-erbB-2 overexpression is a bad prognostic factor in patients with lymph node-positive disease. Unfortunately, there has been no agreement to date on whether c-erbB-2 overexpression is of prognostic significance in patients with lymph node-negative disease. c-erbB-2 overexpression is correlated with the absence of estrogen receptor expression in a number of publications. Correlation between c-erbB-2 overexpression and hormone sensitivity in the clinical setting is less well established and is the focus of ongoing studies. Both preclinical and clinical studies support an association between c-erbB-2 receptor overexpression and resistance to alkylating agents. In contrast, the data for c-erbB-2 and anthracyclines should be viewed in a slightly different manner. Anthracyclines appear to have a greater therapeutic effect in c-erbB-2-positive disease which may be dose sensitive. In c-erbB-2-negative disease not only is the therapeutic effect reduced but there does not appear to be any improved response to higher doses of anthracyclines. The data for c-erbB-2 and the taxanes is still not clear enough to provide any definite conclusions. If there is a correlation it would at present appear to be between paclitaxel and response rates, but this needs to be confirmed in larger studies. Few studies have looked at changes in c-erbB-2 on therapy. Those that have seem to show no significant change on either tamoxifen or chemotherapy.

Use of Trastuzumab in HER2-positive Metastatic Breast Cancer beyond Disease Progression: A Systematic Review of Published Studies

Aims and background

Trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of ErbB, has determined clinical benefit for women affected by metastatic or early stage HER2-positive breast cancer and never previously treated with trastuzumab. Trastuzumab is generally used as first-line treatment of HER2+ metastatic breast cancer and is currently administered beyond progression even without clear evidence supporting such clinical practice. In fact, HER2-positive metastatic breast cancer has a high risk of progressing after first-line therapy, and second-line treatments vary. The aim of the study was to investigate by a systematic review the efficacy of trastuzumab-based treatments beyond progression in HER2-positive metastatic breast cancer.

Materials and methods

We performed a systematic review using Medline, Embase and Cochrane Library data bases and publications in principal meetings or congresses of oncology in Europe and America until September 2008. The main selection criterium was the reporting of time to progression, calculated from the start of each trastuzumab-based therapy to the date of progressive disease or death.

Results

Twelve studies were selected that included a total of 516 patients. The weighted mean time to progression was 23.66 weeks (standard deviation, 4.37) and the median was 26 weeks (range, 13–39). Interestingly, combined trastuzumab plus vinorelbine treatment showed a lower mean and median time to progression (20.59 and 19.57 weeks, respectively), whereas trastuzumab plus capecitabine yielded a mean time to progression of 30.33 weeks.

Conclusions

The added value of the present study has been to provide a quantitative summary measure of time to progression which can be used for comparisons between current and future available regimens.

ErbB2+ metastatic breast cancer treatment after progression on trastuzumab: a cost-effectiveness analysis for a developing country

OBJECTIVE

Breast cancer (BC) and metastatic breast cancer (MBC) are significant causes of deaths amongst women worldwide, including developing countries. The cost of treatment in the latter is even more of an issue than in higher income countries. ErbB2 overexpression is a marker of poor prognosis and the goal for targeted therapy. This study was aimed at evaluating the cost-effectiveness in Colombia of ErbB2+ MBC treatment after progression on trastuzumab.

METHODS

A decision analytic model was constructed for evaluating such treatment in a hypothetical cohort of ErbB2+MBC patients who progressed after a first scheme involving trastuzumab. The alternatives compared were lapatinib+capecitabine (L+C), and trastuzumab+a chemotherapy agent (capecitabine, vinorelbine or a taxane). Markov models were used for calculating progression-free time and the associated costs. Effectiveness estimators for such therapy were identified from primary studies; all direct medical costs based on national fees-guidelines were included. Sensitivity was analyzed and acceptability curves estimated. A 3 % discount rate and third-payer perspective were used within a 5-year horizon.

RESULTS

L+C dominated its comparators. Its cost-effectiveness ratio was COP $49,725,045 per progression-free year. The factors most influencing the results were the alternatives' hazard ratios and the cost of trastuzumab.

CONCLUSION

Lapatinib was cost-effective compared to its alternatives for treating MBC after progression on trastuzumab using a Colombian decision analytic model.

The Significance of c-erbB-2 Overexpression and p53 Expression in Patients With Axillary Lymph Node—Negative Breast Cancer: A Tissue Microarray Study

We conducted this study to examine whether the expression of c-erbB-2 and p53 is the prognostic indicator for patients with early-stage breast cancer in which axillary lymph node metastasis is absent. We examined 326 patients with early-stage breast cancer in which axillary lymph node metastasis is absent. Tissue microarrays were constructed. Following this, immunohistochemical staining was done for estrogen receptor (ER), progesterone receptor (PR), c-erbB2, and p53. The results were as follows: (1) expression of c-erbB-2 was correlated with other clinicopathologic factors (eg, patient's age, presence of menopause, tumor size, histologic and nuclear grade, and presence of hormone receptors such as ER and PR); and (2) expression of p53 was correlated with survival rate, patient's age, presence of menopause, and tumor size. However, these results were not statistically significant. In conclusion, our results indicate that expression of c-erbB-2 and p53 did not have any prognostic value in patients with early-stage breast cancer in which axillary lymph node metastasis is absent.

Association between hormone receptors and HER-2/neu is age-related

PURPOSE

To investigate the association between hormone receptors and HER-2/neu in different age groups of women with breast cancers.

METHODS

A total of 1036 women with breast cancers were recruited. All the patients were divided into nine groups. The expression of hormone receptors and HER-2/neu was studied by IHC, while FISH test was used to determine HER-2/neu status in cases scored IHC 2+. The association between hormone receptors and HER-2/neu in different age groups was evaluated using the χ(2) test. Multivariate analysis was used to find out the independent factors predicting HER-2/neu amplification. Significant findings: The expression of ER and PR was inversely correlated with HER-2/neu status in women aged >40 years. By multivariate analysis, as far as the overall groups were concerned, PR, lymph node status and tumor grade were independently associated with HER-2/neu; Considering the younger age group (≤ 40), the only predictor for HER-2/neu was the tumor grade; Considering the older age group (>40), tumor grade, PR status, tumor size and lymph node status were associated with HER-2/neu overexpression.

CONCLUSIONS

Our data suggest that the association between ER, PR and HER-2/neu is age-related. The negative relationship is only applied for women aged >40 years.

Amplification of Genomic DNA for Decoy Receptor 3 Predicts Post-Resection Disease Recurrence in Breast Cancer Patients

Background

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor (TNFR) superfamily, shows inhibitory effects on Fas-mediated apoptosis. Currently, data are lacking on the correlation between DcR3 and the recurrence of breast cancer. The authors examined DcR3 mRNA expression and genomic amplification in breast cancer, and investigated the effect of DcR3 gene amplification on prognosis of patients.

Methods

A total of 95 patients formed the basis of the current retrospective study. DcR3 mRNA expression in breast cancer tissues was examined by RNase protection assay and in situ hybridization. DcR3 gene amplification was examined by quantitative polymerase chain reaction. The correlation between DcR3 gene amplification status and clinicopathological factors was examined and also the relationship between DcR3-Amp and relapse and survival.

Results

The relative copy numbers of DcR3 genomic DNA correlated significantly with the levels of DcR3 mRNA expression (ρ = 0.755, P = 0.0067). In addition, lymphatic invasion correlated significantly with DcR3 gene amplification (P = 0.012). However, there was no correlation between the remaining clinicopathological factors and DcR3 gene amplification. In the univariate analysis, the recurrence-free survival (RFS) rate of patients who were positive for DcR3 gene amplification was significantly lower than that of patients who were negative for DcR3 gene amplification (P = 0.0271). Multivariate analysis showed that DcR3 gene amplification (P = 0.028) and disease stage (P < 0.001) remained significant independent predictors of RFS.

Conclusions

DcR3 gene amplification was significantly correlated with lymphatic invasion, and also DcR3 gene amplification predicts recurrence after resection, which may be an important prognostic factor in breast cancer patients.

The tyrosine kinase receptor ROR1 is constitutively phosphorylated in chronic lymphocytic leukemia (CLL) cells

Phosphorylation of receptor tyrosine kinases (RTKs) has a key role in cellular functions contributing to the malignant phenotype of tumor cells. We and others have previously demonstrated that RTK ROR1 is overexpressed in chronic lymphocytic leukemia (CLL). Silencing siRNA downregulated ROR1 and induced apoptosis of CLL cells. In the present study we analysed ROR1 isoforms and the phosphorylation pattern in CLL cells (n=38) applying western blot and flow-cytometry using anti-ROR1 antibodies and an anti-phospho-ROR1 antibody against the TK domain. Two major ROR1 bands with the size of 105 and 130 kDa respectively were identified, presumably representing unglycosylated (immature) and glycosylated (mature) ROR1 respectively as well as a 260 kDa band which may represent dimerized ROR1. A ROR1 band of 64 kDa that may correspond to a C-terminal fragment was also noted, present only in the nucleus. The 105 kDa ROR1 isoform was more frequently expressed in non-progressive as compared to progressive CLL patients (p=0.03). The 64, 105, 130 and 260 kDa bands were constitutively phosphorylated both at tyrosine and serine residues. Phosphorylation intensity of the mature (130 kDa) isoform was significantly higher in progressive than in non-progressive disease (p<0.001). Incubation of CLL cells with a mouse anti-ROR1 KNG or an anti-ROR1 CRD mAb respectively induced dephosphorylation of ROR1 before entering apoptosis. In conclusion CLL cells expressed different isoforms of ROR1 which were constitutively phosphorylated. The mature, phosphorylated ROR1 isoform was associated with a progressive disease stage. Targeting ROR1 by mAbs induced specific dephosphorylation and leukemic cell death. ROR1 might be an interesting therapeutic target.

Inhibition of the receptor tyrosine kinase ROR1 by anti-ROR1 monoclonal antibodies and siRNA induced apoptosis of melanoma cells

The receptor tyrosine kinase (RTK) ROR1 is overexpressed and of importance for the survival of various malignancies, including lung adenocarcinoma, breast cancer and chronic lymphocytic leukemia (CLL). There is limited information however on ROR1 in melanoma. In the present study we analysed in seven melanoma cell lines ROR1 expression and phosphorylation as well as the effects of anti-ROR1 monoclonal antibodies (mAbs) and ROR1 suppressing siRNA on cell survival. ROR1 was overexpressed at the protein level to a varying degree and phosphorylated at tyrosine and serine residues. Three of our four self-produced anti-ROR1 mAbs (clones 3H9, 5F1 and 1A8) induced a significant direct apoptosis of the ESTDAB049, ESTDAB112, DFW and A375 cell lines as well as cell death in complement dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC). The ESTDAB081 and 094 cell lines respectively were resistant to direct apoptosis of the four anti-ROR1 mAbs alone but not in CDC or ADCC. ROR1 siRNA transfection induced downregulation of ROR1 expression both at mRNA and protein levels proceeded by apoptosis of the melanoma cells (ESTDAB049, ESTDAB112, DFW and A375) including ESTDAB081, which was resistant to the direct apoptotic effect of the mAbs. The results indicate that ROR1 may play a role in the survival of melanoma cells. The surface expression of ROR1 on melanoma cells may support the notion that ROR1 might be a suitable target for mAb therapy.

Mouse mammary gland is refractory to the effects of ethanol after natural lactation

Ethanol is a dietary factor that dose-dependently increases breast cancer risk in women. We previously have shown that ethanol increases mammary epithelial density through increased branching after dietary exposure during puberty in CD2/F1 mice. To extend these studies to parous mice in a breast cancer model, we used a transgenic mouse model of human parity-associated breast cancer, the FVB-MMTV-Her2/Neu mouse, which overexpresses wildtype EGFR2, resulting in constitutive activation of growth signaling in the mammary epithelium. Here we describe the short-term effects of ethanol feeding on progression through involution. Mice were fed diets supplemented with 0%, 0.5%, 1%, or 2% ethanol for 4, 9, or 14 d starting on day 21 of lactation (that is, at the start of natural postlactational involution). Unlike peripubertal mice exposed to ethanol, postlactational dams showed no changes in body weight; liver, spleen, and kidney weights; and pathology. Ethanol exposure had no effect on mammary gland lobular density and adipocyte size throughout involution. Likewise, the infiltration of inflammatory cells and serum oxidized lipid species were unchanged by diet, suggesting that ethanol feeding had no effect on local inflammation (leukocyte infiltration) or systemic inflammation (oxidized lipids). In conclusion, ethanol exposure of parous dams had no effect on mammary gland structure or the regression of the lactating mammary gland to a resting state. The period of involution that follows natural lactation appears to be refractory to developmental effects of ethanol on mammary epithelium.

Clinical relevance of ErbB-2/HER2 nuclear expression in breast cancer

Background

The biological relevance of nuclear ErbB-2/HER2 (NuclErbB-2) presence in breast tumors remains unexplored. In this study we assessed the clinical significance of ErbB-2 nuclear localization in primary invasive breast cancer. The reporting recommendations for tumor marker prognostic studies (REMARK) guidelines were used as reference.

Methods

Tissue microarrays from a cohort of 273 primary invasive breast carcinomas from women living in Chile, a Latin American country, were examined for membrane (MembErbB-2) and NuclErbB-2 expression by an immunofluorescence (IF) protocol we developed. ErbB-2 expression was also evaluated by immunohistochemistry (IHC) with a series of antibodies. Correlation between NuclErbB-2 and MembErbB-2, and between NuclErbB-2 and clinicopathological characteristics of tumors was studied. The prognostic value of NuclErbB-2 in overall survival (OS) was evaluated using Kaplan-Meier method, and Cox model was used to explore NuclErbB-2 as independent prognostic factor for OS.

Results

The IF protocol we developed showed significantly higher sensitivity for detection of NuclErbB-2 than IHC procedures, while its specificity and sensitivity to detect MembErbB-2 were comparable to those of IHC procedures. We found 33.6% NuclErbB-2 positivity, 14.2% MembErbB-2 overexpression by IF, and 13.0% MembErbB-2 prevalence by IHC in our cohort. We identified NuclErbB-2 positivity as a significant independent predictor of worse OS in patients with MembErbB-2 overexpression. NuclErbB-2 was also a biomarker of lower OS in tumors that overexpress MembErbB-2 and lack steroid hormone receptors.

Conclusions

We revealed a novel role for NuclErbB-2 as an independent prognostic factor of poor clinical outcome in MembErbB-2-positive breast tumors. Our work indicates that patients presenting NuclErbB-2 may need new therapeutic strategies involving specific blockage of ErbB-2 nuclear migration.

The Cyclin D1 (CCND1) A870G polymorphism predicts clinical outcome to lapatinib and capecitabine in HER2-positive metastatic breast cancer

BACKGROUND

Lapatinib plus capecitabine emerged as an efficacious therapy in metastatic breast cancer (mBC). We aimed to identify germline single-nucleotide polymorphisms (SNPs) in genes involved in capecitabine catabolism and human epidermal receptor signaling that were associated with clinical outcome to assist in selecting patients likely to benefit from this combination.

PATIENTS AND METHODS

DNA was extracted from 240 of 399 patients enrolled in EGF100151 clinical trial (NCT00078572; clinicaltrials.gov) and SNPs were successfully evaluated in 234 patients. The associations between SNPs and clinical outcome were analyzed using Fisher's exact test, Kaplan-Meier curves, log-rank tests, likelihood ratio test within logistic or Cox regression model, as appropriate.

RESULTS

There were significant interactions between CCND1 A870G and clinical outcome. Patients carrying the A-allele were more likely to benefit from lapatinib plus capecitabine versus capecitabine when compared with patients harboring G/G (P = 0.022, 0.024 and 0.04, respectively). In patients with the A-allele, the response rate (RR) was significantly higher with lapatinib plus capecitabine (35%) compared with capecitabine (11%; P = 0.001) but not between treatments in patients with G/G (RR = 24% and 32%, respectively; P = 0.85). Time to tumor progression (TTP) was longer in patients with the A-allele treated with lapatinib plus capecitabine compared with capecitabine (median TTP = 7.9 and 3.4 months; P < 0.001), but not in patients with G/G (median TTP = 6.1 and 6.6 months; P = 0.92).

CONCLUSION

Our findings suggest that CCND1A870G may be useful in predicting clinical outcome in HER2-positive mBC patients treated with lapatinib plus capecitabine.

Characterization of BCAR4, a novel oncogene causing endocrine resistance in human breast cancer cells

Resistance to the antiestrogen tamoxifen remains a major problem in the management of estrogen receptor-positive breast cancer. Knowledge on the resistance mechanisms is needed to develop more effective therapies. Breast cancer antiestrogen resistance 4 (BCAR4) was identified in a functional screen for genes involved in tamoxifen resistance. BCAR4 is expressed in 27% of primary breast tumors. In patients treated with tamoxifen for metastized disease high BCAR4 mRNA levels are associated with reduced clinical benefit and progression-free survival. Regarding tumor aggressiveness high BCAR4 mRNA levels are associated with a shorter metastasis free survival and overall survival. In the present study, we investigated the role of BCAR4 in endocrine resistance. Forced expression of BCAR4 in human ZR-75-1 and MCF7 breast cancer cells resulted in cell proliferation in the absence of estrogen and in the presence of various antiestrogens. Inhibition of estrogen receptor 1 (ESR1) expression with small interfering RNA (siRNA), implied that the BCAR4-induced mechanism of resistance is independent of ESR1. Highly conserved BCAR4 homologues of rhesus monkey, green monkey, and the less conserved common marmoset gene induced tamoxifen-resistant cell proliferation, in contrast to the distant BCAR4 homologues of bovine and rabbit. Injection of BCAR4-expressing ZR-75-1 cells into nude mice resulted in rapidly growing tumors. In silico analysis showed that BCAR4 mRNA is highly expressed in human placenta and oocyte, and absent in other normal tissues. In conclusion, BCAR4 is a strong transforming gene causing estrogen-independent growth and antiestrogen resistance, and induces tumor formation in vivo. Due to its restricted expression, BCAR4 may be a good target for treating antiestrogen-resistant breast cancer.

Prognosis and outcome of small (<=1 cm), node-negative breast cancer on the basis of hormonal and HER-2 status

Long-term outcomes and hence the role of adjuvant therapy in patients with small (≤1 cm), node-negative breast cancer remain unclear. This study's objective was to evaluate whether human epidermal growth factor receptor (HER)-2 status is an independent, poor prognostic marker in patients with these tumors and to identify a subgroup of patients with these small tumors who might benefit from adjuvant systemic therapy. All patients with a diagnosis of a node-negative breast tumor measuring ≤1 cm and available HER-2 test results between January 1, 2001, and December 31, 2005, at the three Mayo Clinic sites were identified. Clinicopathologic data were compared in three groups: HER-2(-), HER-2(+), and triple-negative (TN) tumors. Of the 421 tumors identified, 364 (86.5%) were HER-2(-), 28 (6.7%) were HER-2(+), and 29 (6.9%) were TN. The median follow-up time was 1,015 days (range, 1-2,549 days). Groups were balanced in terms of patient age and tumor histology. Eleven patients with HER-2(-) tumors (3.0%), seven with HER-2(+) tumors (25.0%), and eight with TN tumors (27.6%) received adjuvant chemotherapy. Follow-up data were available for 357, 28, and 28 patients in the three groups, respectively. Death rates in the three groups were 6.4% (23 of 357) (one recurrence-related death), 0% (0 of 28), and 7.1% (2 of 28) (one recurrence-related death), respectively. During follow-up, the tumor recurred in nine patients: four were HER-2(-) tumors (1.1%), two were HER-2(+) tumors (7.1%), and three were TN tumors (10.7%). Patients with small, node-negative breast tumors have an excellent prognosis, but HER-2(+) and TN tumors appear to have a higher recurrence rate, warranting consideration for broad use and optimization of systemic adjuvant treatments.

Relevance of BCAR4 in tamoxifen resistance and tumour aggressiveness of human breast cancer

Background:

Breast cancer anti-oestrogen resistance 4 (BCAR4) was identified in a search for genes involved in anti-oestrogen resistance in breast cancer. We explored whether BCAR4 is predictive for tamoxifen resistance and prognostic for tumour aggressiveness, and studied its function.

Methods:

BCAR4 mRNA levels were measured in primary breast tumours, and evaluated for association with progression-free survival (PFS) and clinical benefit in patients with oestrogen receptor (ERα)-positive tumours receiving tamoxifen as first-line monotherapy for advanced disease. In a separate cohort of patients with lymph node-negative, ERα-positive cancer, and not receiving systemic adjuvant therapy, BCAR4 levels were evaluated for association with distant metastasis-free survival (MFS). The function of BCAR4 was studied with immunoblotting and RNA interference in a cell model.

Results:

Multivariate analyses established high BCAR4 mRNA levels as an independent predictive factor for poor PFS after start of tamoxifen therapy for recurrent disease. High BCAR4 mRNA levels were associated with poor MFS and overall survival, reflecting tumour aggressiveness. In BCAR4-expressing cells, phosphorylation of v-erb-b2 erythroblastic leukaemia viral oncogene homolog (ERBB)2, ERBB3, and their downstream mediators extracellular signal-regulated kinase 1/2 and v-akt murine thymoma viral oncogene homolog (AKT) 1/2, was increased. Selective knockdown of ERBB2 or ERBB3 inhibited proliferation, confirming their role in BCAR4-induced tamoxifen resistance.

Conclusion:

BCAR4 may have clinical relevance for tumour aggressiveness and tamoxifen resistance. Our cell model suggests that BCAR4-positive breast tumours are driven by ERBB2/ERBB3 signalling. Patients with such tumours may benefit from ERBB-targeted therapy.

Evaluation of HER2/neu oncoprotein in serum and tissue samples of women with breast cancer: correlation with clinicopathological parameters

BACKGROUND

HER2/neu (HER2) is a proto-oncogen of the EGF Receptor family. The assessment of serum HER2 level is useful for predicting the patients' response to chemotherapy or hormonal therapy and selection of proper patients for treatment with Herceptin. We aimed to compare serum HER2 levels with immunohistochemistry in tumoral tissues and investigate correlation between these levels and various prognostic factors.

MATERIALS AND METHODS

This cross-sectional study was conducted on 75 patients with breast carcinoma referred to surgical ward of Mashhad Imam Reza's hospital from November 2008 to February 2009. Pre-operative serum samples were collected and stored in -20°C. Surgical samples were investigated for the type of carcinoma, tumor size, lymph node metastasis, stage as well as grade of the tumor. Tissue HER2 over-expression was evaluated by immunohistochemistry (IHC) staining and HER2 levels were studied by ELISA method. Statistical analysis was performed by SPSS software.

RESULTS

Serum HER2 cut-off level was 18.4 ng/ml; 46.7% of patients were serum HER2-positive and 43% were IHC positive. There was a high statistical correlation between these two parameters (P=0.018). Statistically, there was no significant correlation between serum HER2 and age, tumor size, stage, grade and metastatic lymph nodes (P>0.05).

CONCLUSION

Serum HER2 level assay can be considered as a complementary method besides tissue methods.

Use of four biomarkers to evaluate the risk of breast cancer subtypes in the women's contraceptive and reproductive experiences study

Epidemiologic studies suggest that some hormone-related risk factors in breast cancer differentially influence risk for disease subtypes classified by the status of the estrogen and progesterone receptors (ER/PR). However, it remains unclear whether human epidermal growth factor receptor 2 (HER2) or p53 expression status further differentiates these exposure-risk group associations. We evaluated the associations of oral contraceptive (OC) use and reproductive factors with incident invasive breast cancer subtypes among 1,197 population-based cases and 2,015 controls from the Los Angeles County or Detroit components of the Women's Contraceptive and Reproductive Experiences Study. Case-control comparisons by ER/PR/HER2/p53 status were conducted by multivariable polychotomous unconditional logistic regression methods. We found that OC use was not associated with any breast cancer subtype as defined by ER/PR/HER2/p53 status, except for a 2.9-fold increased risk of so-called triple-negative tumors (ER(-)/PR(-)/HER2(-)) among women of 45 to 64 years of age who started OC use before age 18. Parity was associated with a decreased risk of luminal A (ER(+) or PR(+), HER2(-)), luminal B (ER(+) or PR(+)/HER2(+)), and ER(-)/PR(-)/HER2(+) tumors. Age at first full-term pregnancy was positively associated with luminal A tumors among older women. Neither of these reproductive factors was associated with triple-negative tumors. Long duration of breast-feeding lowered the risk of triple-negative and luminal A tumors. p53 status did not define further differential risk patterns. Our findings offer evidence of differences in the hormone-related risk factors between triple-negative cancers and other ER/PR/HER2-defined subtypes of breast cancer.

Role of efflux pump activity in lapatinib/caelyx combination in breast cancer cell lines

The aim of this study was to investigate, at preclinical level, efflux pump modulation induced by lapatinib, a small-molecule dual inhibitor of the epidermal growth factor receptor (EGFR), in HER2-negative or HER2-positive breast cancer cell lines (SkBr3 and BRC230). We also evaluated the cytotoxic activity and modulation of biomolecular cellular pathways regulated by caelyx and lapatinib, used singly or in combination, at concentrations corresponding to peak plasma level in the two cell lines. Lapatinib was active in the HER2-overexpressing cell line, SkBr3, but not in BRC230 cell line, which does not express HER2. Conversely, caelyx exerted a cytotoxic effect on both the cell lines. Simultaneous exposure to lapatinib and caelyx in SkBr3 cell line produced an additive cytotoxic effect with dephosphorylation of HER2 and EGFR, an upregulation of p21, and an induction of apoptosis through dephosphorylation of BAD and caspase cleavage. In BRC230, simultaneous treatment induced a synergistic effect that was because of, at least in part, an upregulation of p21. Lapatinib also blocked efflux pumps, such as the breast cancer resistance protein I by increasing the length of time in which caelyx was present in tumor cell cytoplasm, which led to caspase cleavage, BAD dephosphorylation, and apoptosis. Our data indicate that lapatinib used in combination with caelyx is active in HER2-expressing cells, probably because of lapatinib-induced dephosphorylation of the HER2-EGFR pathway, and also in non-HER2-expressing cells, possibly because lapatinib blocks efflux pump activity, increasing the length of time of intracellular exposure to caelyx and thereby increasing its cytotoxic effect.

Impact of American Society of Clinical Oncology/College of American Pathologists guideline recommendations on HER2 interpretation in breast cancer

Accurate assessment of human epidermal growth factor receptor 2 is critical for the management of patients with breast cancer. We set out to study the impact of the 2007 American Society of Clinical Oncology/College of American Pathologists guidelines on the interpretation of human epidermal growth factor receptor 2 IHC results and its correlation with fluorescence in situ hybridization results. Invasive breast carcinomas with IHC HercepTest 3+ were retrieved from the archive of Mayo Clinic Rochester. The human epidermal growth factor receptor 2 slides were rereviewed, and results were recorded as percentage of invasive tumor cells with 3+, 2+, 1+, and 0 staining intensity. Human epidermal growth factor receptor 2 gene amplification by fluorescence in situ hybridization was performed on all tumors with 3+ staining in 70% or less of tumor cells. Of the 141 cases studied, 12 cases showed intense membrane staining in 11% to 30% of the invasive tumor cells and would have been scored as 2+ according to the new American Society of Clinical Oncology/College of American Pathologists guidelines. Of these 12 cases, 6 were positive for human epidermal growth factor receptor 2 gene amplification by fluorescence in situ hybridization (ratio >2.2), 4 cases were negative (HER2/CEP17 ratio of < 1.8), and 2 cases were equivocal (ratio of 1.8-2.2). One human epidermal growth factor receptor 2-positive case showed dramatic intratumoral heterogeneity with high-level amplification (ratio of 12.2) in the IHC 3+ area and no amplification (ratio of 1.0) in the IHC 1+/2+ areas. The 2007 American Society of Clinical Oncology/College of American Pathologists guidelines down-scored 2.8% of tumors from human epidermal growth factor receptor 2-positive (IHC 3+) to human epidermal growth factor receptor 2-negative (IHC 2+ equivocal and fluorescence in situ hybridization negative) in this study. Clinical studies are needed to determine whether the updated guidelines are better at predicting response to anti-human epidermal growth factor receptor 2 therapy.

Anti-EGFR Therapy: Mechanism and Advances in Clinical Efficacy in Breast Cancer

This review will focus on recent advances in the application of antiepidermal growth factor receptor (anti-EGFR) for the treatment of breast cancer. The choice of EGFR, a member of the ErbB tyrosine kinase receptor family, stems from evidence pinpointing its role in various anti-EGFR therapies. Therefore, an increase in our understanding of EGFR mechanism and signaling might reveal novel targets amenable to intervention in the clinic. This knowledge base might also improve existing medical treatment options and identify research gaps in the design of new therapeutic agents. While the approved use of drugs like the dual kinase inhibitor Lapatinib represents significant advances in the clinical management of breast cancer, confirmatory studies must be considered to foster the use of anti-EGFR therapies including safety, pharmacokinetics, and clinical efficacy.

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.

An overview of HER-targeted therapy with lapatinib in breast cancer

Breast cancer is a global public health burden with more than one million new diagnoses worldwide each year. As a significant proportion of women with early-stage breast cancer experience a relapse and metastatic breast cancer is generally incurable, therapeutic innovations are ongoing. One notable innovation in recent decades has been the identification of a subset of breast cancers that overexpress the transmembrane glycoprotein human epidermal growth factor receptor 2 (HER2) and the consequent development of HER2-targeted therapy. Given the significant benefits demonstrated with the HER2-targeted monoclonal antibody, trastuzumab, in the adjuvant and metastatic settings, investigators have endeavored to develop novel mechanisms for disrupting HER2-mediated signaling. Lapatinib, an orally available HER1- and HER2-targeted tyrosine kinase inhibitor, represents one such notable innovation. Lapatinib is currently being evaluated in both the adjuvant and metastatic settings and was recently approved by the United States Food and Drug Administration in combination with capecitabine, for the treatment of women with HER2-positive, pretreated, metastatic breast cancer. However, the ideal strategy for incorporating novel HER2-targeted agents, including lapatinib, into existing management paradigms is uncertain.

Single-agent lapatinib for HER2-overexpressing advanced or metastatic breast cancer that progressed on first- or second-line trastuzumab-containing regimens

BACKGROUND

This phase II study evaluated the efficacy and safety of lapatinib in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer that progressed during prior trastuzumab therapy.

PATIENTS AND METHODS

Women with stage IIIB/IV HER2-overexpressing breast cancer were treated with single-agent lapatinib 1250 or 1500 mg once daily after protocol amendment. Tumor response according to RECIST was assessed every 8 weeks. HER2 expression was assessed in tumor tissue by immunohistochemistry and FISH.

RESULTS

Seventy-eight patients were enrolled in the study. Investigator and independent review response rates [complete response (CR) or partial response (PR)] were 7.7% and 5.1%, and clinical benefit rates (CR, PR, or stable disease for >or=24 weeks) were 14.1% and 9.0%, respectively. Median time to progression was 15.3 weeks by independent review, and median overall survival was 79 weeks. The most common treatment-related adverse events were rash (47%), diarrhea (46%), nausea (31%), and fatigue (18%).

CONCLUSIONS

Single-agent lapatinib has clinical activity with manageable toxic effects in HER2-overexpressing breast cancer that progressed on trastuzumab-containing therapy. Studies of lapatinib-based combination regimens with chemotherapy and other targeted therapies in metastatic and earlier stages of breast cancer are warranted.

Human Epidermal Growth Factor Receptor 2 Overexpression As a Prognostic Factor in a Large Tissue Microarray Series of Node-Negative Breast Cancers

Purpose

Human epidermal growth factor receptor 2 gene (HER2) is associated with a poorer outcome in node-positive breast cancer, but the results are conflicting in node-negative disease. This study assessed the prognostic impact of HER2 overexpression/amplification in a large series of node-negative breast cancers.

Patients and Methods

A tissue microarray (TMA) series was constructed consisting of 4,444 invasive breast cancers diagnosed in British Columbia from 1986 to 1992. Within this series, 2,026 patients were node negative, of whom 70% did not receive adjuvant systemic therapy. The TMA series was assessed for estrogen receptor (ER) and HER2. Logistic regression modeling was used to estimate odds ratios at the 10-year follow-up.

Results

HER2 was positive in 10.2% of the node-negative cohort. In this cohort, an inferior outcome was seen in patients with HER2-positive tumors compared with HER2-negative tumors for 10-year relapse-free survival (RFS; 65.9% v 75.5%, respectively; P = .01), distant RFS (71.2% v 81.8%, respectively; P = .004), and breast cancer–specific survival (BCSS; 75.5% v 86.3%, respectively; P = .001). A trend for a worse overall survival was also seen (P = .06). HER2 was an independent poor prognostic factor for RFS and BCSS at 10 years, with odds ratios of 1.71 (P = .01) and 2.03 (P = .003), respectively. The number of HER2-positive tumors that were ≤ 1 cm was small, but there was a trend for a worse outcome in T1b tumors.

Conclusion

HER2 overexpression/amplification is correlated with a poorer outcome in node-negative breast cancer. Larger studies are needed to more clearly define the prognostic impact of HER2 in tumors ≤ 1 cm, particularly within the separate hormone receptor subgroups.

HER2: The Neu Prognostic Marker for Breast Cancer

A fundamental mechanism of genetic alteration is amplification of entire gene sequences that results in overexpression of a gene product or protein. If the amplified gene is a member of the oncogene family and/or a regulator of DNA replication or cell cycle progression, overexpression of this oncoprotein may result in enhanced growth advantages for these cells. Amplification of one such oncogene, HER2 (neu, erbB-2), in up to 35% of human breast cancers is associated with a poor prognosis but may predict response to various therapeutic modalities. FDA-approved assays are available to detect the HER2 protein receptor or the HER2 gene sequence to determine eligibility for Herceptin treatment or adriamycin treatment in node positive patients, respectively. As testing for HER2 is becoming more common in the clinical laboratory, we provide an overview of the biology, diagnostic methods, and emerging clinical value of HER2 gene amplification.

Lower level of MAPK expression is associated with anthracycline resistance and decreased survival in patients with hormone receptor negative breast cancer

INTRODUCTION

Hormone receptor negative breast cancer is encountered in about 30% of all patients with breast cancer and is considered as a prognostically unfavorable subset. The aim of this study is to evaluate the prognostic impact of various molecular markers in patients with receptor negative breast cancer.

METHODS

Tumor specimens from 140 patients with receptor negative (ER, PR) breast cancer were analyzed for MAPK, Her-2/neu, EGFR and PI3K expression by immunohistochemistry. The prognostic significance of these molecular factors, in addition to various prognostic variables were determined with respect to disease-free and overall survival.

RESULTS

Nineteen (13.6%), 45 (32.1%), 16 (11.4%) and 47 (33.5%) patients had positive staining for EGFR, PI3K, Her-2/neu and MAPK, respectively. Twenty-three patients with positive MAPK (16.4%) had a high level of expression (score 4-7) and 24 (17.1%) had a low score (1-3). A lower percentage of MAPK expression was significantly associated with a poorer OS (p = 0.03) and a tendency for shorter DFS (p = 0.08) among those who were positive for MAPK. Anthracycline resistance remained the only independent significant variable for OS by Cox regression analysis (p = 0.001, HR:26.1). In patients with recurrent disease, median survival after initial relapse was 16.8 months. MAPK was determined as the only prognostic factor for this endpoint. Patients with higher level of MAPK staining showed significantly shorter survival following initial recurrence (p = 0.04).

CONCLUSION

MAPK expression is a significant prognostic factor for non-metastatic patients with hormone receptor breast cancer. A lower level of staining is shown to be associated with with antracycline resistance and oveall survival, whereas a higher expression level is correlated with shorter survival following initial relapse, suggesting possible role of different molecular mechanisms pertaining to tumor progression once recurrence occurs. Further translational research is required to elucidate molecular mechanisms of the cross-talk between intracellular signaling and molecular pathways leading to drug resistance in patients with receptor negative breast cancer.

Focus on ERBB2

The ERBB2 (HER2) gene codes for a tyrosine kinase receptor that activates pathways involved in cell division, differentiation and apoptosis. Gene amplification, and as a result protein overexpression, are commonly seen in breast tumors and correlate with poor prognosis. The overexpressed protein is the target of trastuzumab, a monoclonal antibody routinely used in clinical practice. A new tyrosine kinase inhibitor, lapatinib, is already an alternative in women progressing despite treatment with trastuzumab. Using comprehensive tagging approaches, highly-powered association studies concluded that ERBB2 was unlikely to be a breast cancer predisposition gene. ERBB2 pharmacogenomics are of little relevance at present, since we have no knowledge of polymorphisms in the gene that could affect the binding, efficacy or tolerability of trastuzumab or lapatinib. There is minor contribution from hepatic cytochrome CYP2C19 to the metabolism of lapatinib, whereas in vitro studies have shown the drug to be a substrate for the transporter P-glycoprotein. If, and how, the pharmacokinetics of lapatinib would be altered in individuals carrying polymorphisms in CYP2C19 or ABCB1 – the gene that codes for the P-glycoprotein – is yet to be determined.

Immunogenicity and safety profiles of genetic vaccines against human Her-2/neu in cynomolgus monkeys

Her-2/neu is a well-characterized tumor-associated antigen, the overexpression of which in human carcinomas correlates with a poor prognosis. Here, we evaluated Her-2/neu-specific humoral and cellular immune responses in immunized monkeys after immunization with nonreplicating adenovirus (AdHM) expressing the extracellular and transmembrane domain of human Her-2/neu (HM) and/or naked DNA vaccine (pHM-hGM-CSF) expressing human granulocyte-macrophage colony-stimulating factor together with HM. Priming of monkeys with AdHM generated Her-2/neu-specific long-lasting antibody production. Furthermore, these Her-2/neu-specific antibodies produced by AdHM immunization, some of which shared epitope specificity with Herceptin, were able to induce antibody-dependent cellular cytotoxicity against Her-2-expressing target cells. Cellular immune responses were elicited in all monkeys immunized with Her-2/neu-expressing vaccine; interferon-gamma was secreted when these splenocytes were restimulated with Her-2/neu-expressing autologous cells, and immunization with AdHM induced Her-2/neu-specific lymphoproliferative responses. Further, immunization with pHM-hGM-CSF before AdHM immunization noticeably enhanced cytotoxic T-lymphocyte activity. In addition, we observed no abnormalities that would indicate that the genetic vaccines had toxic effects in the immunized monkeys. Thus, we can conclude that our genetic vaccines efficiently elicited Her-2/neu-specific humoral and cellular immune responses without causing severe adverse effects in nonhuman primates and that as such they warrant further clinical investigation.

Efficacy and safety of lapatinib as first-line therapy for ErbB2-amplified locally advanced or metastatic breast cancer

PURPOSE

This study (EGF20009) assessed the efficacy and tolerability of two lapatinib administration schedules as first-line monotherapy in women with ErbB2-amplified locally advanced or metastatic breast cancer.

PATIENTS AND METHODS

Patients with ErbB2-amplified, locally advanced or metastatic breast cancer previously untreated in the metastatic setting were randomly assigned to one of two lapatinib dose cohorts and received either 1,500 mg once daily or 500 mg twice daily. Clinical response was assessed at weeks 8 and 12 and every 12 weeks thereafter.

RESULTS

A total of 138 patients were treated with lapatinib for a median of 17.6 weeks. The overall response rate (complete response [CR] plus partial response [PR]) was 24% in the intent-to-treat population, and 31% of patients derived clinical benefit (CR, PR, or stable disease for >or= 24 weeks). The median time to response was 7.9 weeks, and the progression-free survival rates at 4 and 6 months were 63% and 43%, respectively. The most common lapatinib-related adverse events (AEs) were diarrhea, rash, pruritus, and nausea, and these events were primarily grade 1 or 2. There were no significant differences in clinical activity or the AE profile between the dosing schedules.

CONCLUSION

Lapatinib demonstrated clinical activity and was well tolerated as first-line therapy in ErbB2-amplified locally advanced or metastatic breast cancer. This study supports further evaluation of lapatinib in first-line and early-stage ErbB2-overexpressing breast cancer.

A combination of chemoimmunotherapies can efficiently break self-tolerance and induce antitumor immunity in a tolerogenic murine tumor model

Her-2/neu is a well-characterized tumor-associated antigen overexpressed in human carcinomas such as breast cancer. Because Her-2/neu is a self-antigen with poor immunogenicity due to immunologic tolerance, active immunotherapy targeting Her-2/neu should incorporate methods to overcome immunologic tolerance to self-proteins. In this study, we developed a tolerogenic tumor model in mice using mouse Her-2/neu as self-antigen and investigated whether genetic vaccination with DNA plasmid and/or adenoviral vector expressing the extracellular and transmembrane domain of syngeneic mouse Her-2/neu or xenogenic human Her-2/neu could induce mouse Her-2/neu-specific CTL responses. Interestingly, adenoviral vectors expressing xenogenic human Her-2/neu (AdhHM) proved capable of breaking immune tolerance and of thereby inducing self-reactive CTL and antibodies, but not to the degree required to induce therapeutic antitumor immunity. In attempting to generate therapeutic antitumor immunity against established tumors, we adopted several approaches. Treatment with agonistic anti-glucocorticoid-induced TNFR family-related receptor (GITR) antibody plus AdhHM immunization significantly increased self-reactive CTL responses, and alpha-galactosylceramide (alphaGalCer)-loaded dendritic cells (DC) transduced with AdhHM were shown to break self-tolerance in a tolerogenic murine tumor model. Furthermore, gemcitabine treatment together with either AdhHM plus agonistic anti-GITR antibody administration or alphaGalCer-loaded DC transduced with AdhHM showed potent therapeutic antitumor immunity and perfect protection against preexisting tumors. Gemcitabine treatment attenuated the tumor-suppressive environment by eliminating CD11b(+)/Gr-1(+) myeloid-derived suppressor cells. When combined with immunotherapies, gemcitabine offers a promising strategy for the Ag-specific treatment of human cancer.

Regression of early and intermediate stages of colon cancer by targeting multiple members of the EGFR family with EGFR-related protein

A role of the epidermal growth factor receptor (EGFR) family has been suggested in colon cancer etiology, progression, and/or severity. Our recently identified pan-erbB inhibitor EGFR-related protein (ERRP) targets EGFRs by attenuating their activation and subsequent signaling leading to cellular growth inhibition. In the present study, we evaluated the therapeutic effectiveness of ERRP on early and intermediate stages of colon cancer by examining regression of chemically induced aberrant crypt foci (ACF) in the colon of CF1 mice and intestinal adenomas in APC(Min+/-) (Min) mice. After formation of ACF or adenomas, the mice were injected (i.p.) with ERRP (50 microg/mouse) for 10 consecutive days. This treatment significantly reduced the number of ACF from 25.0 +/- 3.0 (controls) to 14.9 +/- 1.6 (ERRP-treated; P = 0.011) and also reduced their size (P < 0.01). In Min mice, ERRP caused the regression of adenomas throughout the small intestine (P < 0.05) and reduced their size (P < 0.001). This could partly be attributed to inhibition of proliferation and stimulation of apoptosis in the intestinal mucosa and was associated with decreased activation of several EGFR family members, suppression of downstream effector nuclear factor kappaB and down-regulation of cyclooxygenase-2. ERRP-induced attenuation of EGFR activation could be due to increased sequestration of the ligand(s) by ERRP, rendering them unavailable for binding to and activation of the receptor. In conclusion, our data show that ERRP is effective in regressing both early and intermediate intestinal lesions and could be an effective therapeutic agent for colon cancer.

Downregulation of erbB3 abrogates erbB2-mediated tamoxifen resistance in breast cancer cells

Receptor tyrosine kinase activity is essential for erbB2 (HER2/neu) promotion of breast carcinogenesis, metastasis and therapeutic resistance. erbB2 kinase can be activated by dimerization with another erbB receptor, most of which bind ligands. Of these, the erbB2/erbB3 heterodimer is the most potent oncogenic complex. erbB2 reportedly requires erbB3 to promote cellular proliferation, although this may occur without changes in erbB2 tyrosine kinase activity in some model systems. Our investigations focus on the role(s) of erbB3 in erbB2-associated kinase activity and tamoxifen resistance. Using tumor-derived cell lines from wild type rat c-neu transgenic mice and human breast cancers, we demonstrate that erbB3 plays a critical role in the activation of erbB2 tyrosine kinase activity and erbB2-associated tumorigenesis. Mechanistically, downregulation of erbB3 by specific siRNA reduces erbB2 tyrosine phosphorylation, decreases the PI-3K/Akt signaling, and inhibits mammary/breast cancer cell proliferation and colony formation. Specific erbB3 siRNA sensitizes erbB2 transfected MCF-7 cells (MCF-7/erbB2) to tamoxifen-associated inhibition of both cell growth and colony formation and enhances tamoxifen-induced apoptosis, in contrast to control siRNA transfected MCF-7/erbB2 cells which are tamoxifen-resistant. Our data indicates that erbB2/erbB3 heterodimerization is a prerequisite for erbB2 tyrosine kinase activation in mammary/breast cancer cells and that downregulation of erbB3 inhibits erbB2-associated procarcinogenic activity via inactivation of the PI-3K/Akt pathway. Furthermore, erbB3 also contributes to erbB2-mediated tamoxifen resistance and therefore may be a clinically relevant therapeutic target in addition to erbB2.

Coexistence of the loss of heterozygosity at the PTEN locus and HER2 overexpression enhances the Akt activity thus leading to a negative progesterone receptor expression in breast carcinoma

Serine/threonine kinase Akt/PKB is known to regulate divergent cellular processes, including apoptosis, proliferation, differentiation, and metabolism. Akt is activated by a variety of stimuli, through such growth factor receptors as HER2, in phosphoinositide-3-OH kinase (PI3K)-dependent manner. A loss of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) function also activates Akt. It has recently been shown that Akt activation is associated with a worse outcome among endocrine treated breast cancer patients and that it also inhibits the progesterone receptor (PR) expression via the PI3K/Akt pathway in breast cancer cells. Therefore, the PI3K/Akt signaling pathway has recently attracted considerable attention as a new target for effective therapeutic strategies. In the present study, we investigated the relationship between Akt activation and either HER2 overexpression or PTEN gene alteration, as well as the PR expression. We analyzed the incidence of LOH at the PTEN locus in 138 breast cancer patients, using our new system for microsatellite analysis, called high-resolution fluorescent microsatellite analysis (HRFMA). We showed Akt activation to significantly correlate with HER2 overexpression or LOH at the PTEN gene locus while inversely correlating with the PR expression. In addition, when LOH at the PTEN gene locus and HER2 overexpression occurred simultaneously, the incidence of Akt activation and reduced PR expression was significant. The association between Akt activation and PR negative expression was observed even in the ER-positive cases. Our results suggest that simultaneous PTEN LOH and HER2 overexpression enhances Akt activation and may thus lead to a negative PR expression.

Anti-erbB-2 antibody trastuzumab in the treatment of HER2-amplified breast cancer

Human epidermal growth factor receptor-2 (HER2/erbB-2) is a member of a family of four transmembrane receptor tyrosine kinases that regulate cell growth, survival and differentiation via multiple signal transduction pathways. Amplification of the HER2 gene occurs in 20-25% of human breast cancers. This amplification event is an independent adverse prognostic factor as well as a predictive factor for increased response to doxorubicin-based combination chemotherapy, response to trastuzumab and decreased response to hormonal therapy. Methods for detecting protein overexpression or gene amplification in clinical tumor specimens include immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) techniques, with the latter considered by some to be more accurate. Trastuzumab (Herceptin) is a recombinant humanized monoclonal antibody which targets an epitope in the extracellular domain of the HER2 protein. Preclinical models demonstrated that this antibody has significant anti-tumor activity as a single agent and has synergy with certain chemotherapeutic drugs. Phase II and III clinical trials performed in women with metastatic breast cancer that overexpress HER2 have shown that trastuzumab has clinical activity when used as first-, second- or third-line monotherapy, and improves survival when used as first-line therapy in combination with chemotherapy. Newer combinations with numerous chemotherapeutic drugs have also shown significant clinical activity in phase II studies. In all of these trials, trastuzumab was generally well-tolerated, but cardiac toxicity (particularly when the antibody was combined with anthracyclines) was an unexpected adverse effect. Although trastuzumab is currently usually administered on a weekly intravenous schedule, evidence suggests that a triple dose of the drug given once every three weeks has a pharmacokinetic profile expected to be equally efficacious. Neither the optimal schedule nor the optimal duration of trastuzumab therapy has yet been clearly defined in controlled clinical trials. Current clinical investigations of trastuzumab include its use in both the adjuvant and neoadjuvant settings as well as in combination with other chemotherapy drugs or new biologic targeted agents.

Real-time PCR complements immunohistochemistry in the determination of HER-2/neu status in breast cancer

Background

The clinical benefit of determining the status of HER-2/neu amplification in breast cancer patients is well accepted. Although immunohistochemistry (IHC) is the most frequently used method to assess the over-expression of HER-2 protein, fluorescent in-situ hybridization (FISH) is recognized as the "gold standard" for the determining of HER-2/neu status. The greatest discordance between the two methods occurs among breast tumors that receive an indeterminate IHC score of 2+. More recently, a real-time polymerase chain reaction (PCR) assay using the LightCycler^® has been developed for quantifying HER-2/neu gene amplification. In this study, we evaluated the sensitivity and specificity of a commercially available LightCycler assay as it compares to FISH. To determine whether this assay provides an accurate alternative for the determination of HER-2/neu status, we focused primarily on tumors that were deemed indeterminate or borderline status by IHC.

Methods

Thirty-nine breast tumors receiving an IHC score of 2+ were evaluated by both FISH and LightCycler^® technologies in order to determine whether quantitative real-time PCR provides an accurate alternative for the determination of HER-2/neu status.

Results

We found a high concordance (92%) between FISH and real-time PCR results. We also observed that 10% of these tumors were positive for gene amplification by both FISH and real-time PCR.

Conclusion

The data show that the results obtained for the gene amplification of HER-2/neu by real-time PCR on the LightCycler^® instrument is comparable to results obtained by FISH. These results therefore suggest that real-time PCR analysis, using the LightCycler^®, is a viable alternative to FISH for reassessing breast tumors which receive an IHC score of 2+, and that a combined IHC and real-time PCR approach for the determination of HER-2 status in breast cancer patients may be an effective and efficient strategy.

Akt is frequently activated in HER2/neu-positive breast cancers and associated with poor prognosis among hormone-treated patients

Akt/PKB is a serine/threonine kinase that plays an important role in survival when cells are exposed to different apoptotic stimuli. Aberrant activation of Akt/PKB in breast carcinoma is associated with poor prognosis and resistance to endocrine therapy and chemotherapy. The Akt signaling pathway currently attracts considerable attention as a new target for effective therapeutic strategies. We therefore investigated the relationship between activation of Akt and clinicopathologic variables including hormone receptor and HER2/neu status. Breast cancer tissues obtained from 252 patients were utilized for this study. We evaluated Akt activation by immunohistochemical assessment of the expression of phosphorylated Akt (pAkt) at Ser-473. Eighty-four cases (33.3%) were diagnosed as positive for pAkt expression. pAkt was significantly associated with HER2/neu overexpression (p < 0.0001). There was an inverse correlation between pAkt and PR expression (p = 0.0321); however, there was no association between pAkt and ER expression. Survival analysis showed that pAkt positivity was associated with poor disease-free survival in cases with postoperative hormone therapy; however, there was no association in cases without hormone therapy. Our results indicate that Akt activation induced poor prognosis in patients who received adjuvant hormone therapy. This finding suggests that inhibition of the Akt signaling pathway may increase the efficacy of hormone therapy and improve the prognosis of patients who receive adjuvant hormone therapy.