EGFR gene and protein expression in breast cancers

Ras Signaling in Breast Cancer

Ras proteins mediate extracellular and cytoplasmic signaling networks via receptor tyrosine kinase. The Ras pathway induces activation of signaling molecules involved in cell proliferation and growth, cell survival and apoptosis, metabolism, and motility. Although Ras mutations in breast cancer are not frequently reported, hyperactivation of Ras signaling plays an important role in breast cancer growth and progression. Oncogenic Ras activation occurs via loss of Ras GTPase-activating proteins, overexpression of growth factor receptor, and stimulation by various cytokines. Effective control of oncogenic Ras is one of the therapeutic strategies in breast cancer. The mechanisms of intracellular localization, activation, and signaling pathway of Ras in cancer have been used to develop therapeutic candidates. Recent studies have reported an effective therapy for breast cancer by inhibition of enzymes involved in the posttranslational modification of Ras, such as farnesyltransferase and geranylgeranyltransferase 1, and anti-cancer therapies targeting the epidermal growth factor receptor (EGFR). Emerging targets involved in EGF-mediated Ras activity in breast cancer have shed new insight into Ras activation in breast cancer progression. These alternative mechanisms for Ras signaling pathway may suggest novel therapeutic approaches for targeting Ras in breast cancer. In spite of the difficulties in targeting Ras protein, important discoveries highlight the direct inhibition of Ras activity. Further studies may elucidate the effects of targeting Ras protein and the clinical relevance thereof.

The Accuracy of Determining Cluster Size by Analyzing Ripley’s K Function in Single Molecule Localization Microscopy

Ripley’s K function was developed to analyze the spatial distribution characteristics in point pattern analysis, including geography, economics and biomedical research. In biomedical applications, it is popularly used to analyze the clusters of proteins on the cell plasma membrane in single molecule localization microscopy (SMLM), such as photo activated localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), universal point accumulation imaging in nanoscale topography (uPAINT), etc. Here, by varying the parameters of the simulated clusters on a modeled SMLM image, the effects of cluster size, cluster separation and protein ratio inside/outside the cluster on the accuracy of cluster analysis by analyzing Ripley’s K function were studied. Although the predicted radius of clusters by analyzing Ripley’s K function did not exactly correspond to the actual radius, we suggest the cluster radius could be estimated within a factor of 1.3. Employing peak analysis methods to analyze the experimental epidermal growth factor receptor (EGFR) clusters at fibroblast-like cell lines derived from monkey kidney tissue - COS7 cell surface observed by uPAINT method, the cluster properties were characterized with errors. Our results present quantification of clusters and can be used to enhance the understanding of clusters in SMLM.

EGF Level in Hepatoid Gland Adenomas and Hepatoid Gland Epitheliomas in Dogs After Administering Tamoxifen

BACKGROUND/AIM

Neoplastic lesions of perianal glands account for approximately 10% of all skin cancer cases in dogs. They occur in many dog breeds, usually in male animals aged over 6 years. Due to their hormone-dependency, tamoxifen can be used in antineoplastic treatment. The aim of the study was to measure epidermal growth factor (EGF) levels in the serum of dogs with perianal tumours after tamoxifen treatment and to use it as a prognostic factor for further treatment.

MATERIALS AND METHODS

The study was performed on 19 male dogs aged between 6 and 14 years, diagnosed with neoplastic hyperplasia in the perianal region. The control group comprised 10 healthy dogs brought in for routine castration. The research material comprised blood drawn from the animals and tumour specimens for histopathology. The study group received 1-month treatment with tamoxifen. Blood serum was then tested for 17-β oestradiol level, and for EGF level on the first day of the therapy and 6 months after treatment completion.

RESULTS

Hepatoid gland adenomas were diagnosed in 10 cases, and hepatoid gland epitheliomas in nine cases. Elevated 17-β oestradiol levels were observed in all dogs. On the first day of treatment with tamoxifen, the serum EGF levels in all study groups were higher than in the control group. At the 6-month follow-up, the EGF levels were significantly reduced in hepatoid gland adenoma cases compared to those taken on the first day of treatment of tamoxifen, while in animals with hepatoid gland epithelioma, it was greatly increased and was correlated with relapse.

CONCLUSION

Perianal gland tumours are characterised by EGF overexpression, which can be helpful in early-stage prognosis and treatment. An increase in EGF levels 6 months after tamoxifen therapy correlates with disease progression and may be a useful prognostic factor.

Copy number profiling of oncogenes in ductal carcinoma in situ of the male breast

Characterizing male breast cancer (BC) and unraveling male breast carcinogenesis is challenging because of the rarity of this disease. We investigated copy number status of 22 BC-related genes in 18 cases of pure ductal carcinoma in situ (DCIS) and in 49 cases of invasive carcinoma (IC) with adjacent DCIS (DCIS-AIC) in males using multiplex ligation-dependent probe amplification (MLPA). Results were compared to female BC and correlated with survival. Overall, copy number ratio and aberration frequency including all 22 genes showed no significant difference between the 3 groups. Individual unpaired analysis revealed a significantly higher MTDH copy number ratio in IC compared to DCIS-AIC and pure DCIS (P = 0.009 and P = 0.038, respectively). ADAM9 showed a significantly lower copy number aberration frequency in male BC, compared to female BC (P = 0.020). In DCIS-AIC, MTDH, CPD, CDC6 and TOP2A showed a lower frequency of copy number increase in males compared to females (P < 0.001 for all 4 genes). In IC, CPD gain and CCNE1 gain were independent predictors of poor overall survival. In conclusion, male DCIS and IC showed a similar copy number profile for 21 out of 22 interrogated BC-related genes, illustrating their clonal relation and the genetically advanced state of male DCIS. MTDH showed a higher copy number ratio in IC compared to adjacent and pure DCIS and may therefore play a role in male breast carcinogenesis. Differences were detected between male and female DCIS for 4 genes pointing to differences in breast carcinogenesis between the sexes.

Prognostic Evaluation of Epidermal Growth Factor Receptor (EGFR) Genotype and Phenotype Parameters in Triple-negative Breast Cancers

BACKGROUND

Epidermal growth factor receptor (EGFR) aberrations have been implicated in the pathogenesis of triple-negative breast cancer (TNBC) but their impact on prognosis and, therefore, druggability, remain controversial. Herein, we studied EGFR aberrations at different molecular levels and assessed their prognostic impact in patients with operable TNBC treated with adjuvant anthracycline-based chemotherapy.

MATERIALS AND METHODS

We evaluated the prognostic impact of EGFR gene status by fluorescent in situ hybridization (FISH), EGFR coding mutations by Sanger and next-generation sequencing, relative EGFR messenger RNA (mRNA) levels by qPCR (upper quartile) and EGFR and p53 protein expression by immunohistochemistry (IHC), in 352 centrally-assessed tumors from an equal number of TNBC patients.

RESULTS

Approximately 53.5% of the tumors expressed EGFR, 59.3% p53 and 35.9% both EGFR and p53 proteins; 4.1% showed EGFR gene amplification and 4.4% carried EGFR mutations. The latter were located outside the druggable kinase domain region and presented at low frequencies. Amplification and mutations overlapped only in one case of glycogen-rich carcinoma. EGFR and CEN7 copies were higher in tumors from older patients (p=0.002 and p=0.003, respectively). Patients with amplified tumors (n=11) had excellent prognosis (0 relapses and deaths). Upon multivariate analysis, high EGFR copies conferred significantly favorable disease-free survival (HR=0.57, 95% CI 0.36-0.90, Wald's p=0.017) and high CEN7 copies favorable overall survival (HR=0.49, 95% CI=0.29-0.83, Wald's p=0.008). Patients with EGFR-/p53+ and EGFR+/p53- tumors had significantly higher risk for relapse than those with EGFR-/p53- and EGFR+/p53+ tumors (HR=1.73, 95% CI=1.12-2.67, Wald's p=0.013).

CONCLUSION

EGFR gene amplification and mutations are rare in TNBC, the latter of no apparent clinical relevance. Surrogate markers of EGFR-related chromosomal aberrations and combined EGFR/p53 IHC phenotypes appear to be associated with favorable prognosis in patients with operable TNBC receiving conventional adjuvant chemotherapy.

Breast cancers with EGFR and HER2 co-amplification favor distant metastasis and poor clinical outcome

ErbB signaling serves essential roles in invasive ductal carcinoma (IDC). The aim of the present study was to assess gene amplification in ErbB family members in IDC with clinical implications. Quantitative polymerase chain reaction and fluorescence in situ hybridization were performed on formalin-fixed paraffin-embedded tumor samples for gene amplification detection. The clinical and histopathological characteristics, as well as the prognostic significance, were analyzed. Among the 119 IDC patients evaluated, epidermal growth factor receptor [EGFR; also known as human epidermal growth factor receptor (HER)1], HER2, HER3 and HER4 gene amplification was observed in 30 (25.2%), 44 (36.9%), 0 (0.0%) and 1 (0.8%) patients, respectively. EGFR amplification was associated with estrogen receptor status (P=0.028) and higher possibilities of recurrence (P=0.015) and distant metastasis (following initial surgery) (P=0.011). In survival analysis, EGFR amplification was also associated with disease-free survival (DFS) (P=0.001) and overall survival (OS) (P=0.003). HER2 amplification was associated with larger tumor size (P=0.006), later clinical stage (P=0.003) and distant metastasis (following initial surgery) (P=0.006). In survival analysis, HER2 amplification was also associated with DFS (P=0.011). Notably, the present study identified a group of patients in whom EGFR and HER2 were co-amplified. This group of patients appeared to have a higher possibility of metastasis (when diagnosed) (P=0.014) and distant metastasis (following initial surgery) (P<0.001). In survival analysis, these patients were noticed to be associated with DFS (P<0.001) and OS (P=0.002). With respect to treatment regimen, this was also true for the DFS association with chemotherapy (P<0.001), radiotherapy (P<0.001) and hormonal therapy (P=0.001). The present results suggest that EGFR and HER2 amplification favor distant metastasis following initial surgery and are significantly associated with poor clinical outcome in breast cancer patients.

Detection of Gene Amplification by Multiplex Ligation-Dependent Probe Amplification in Comparison with In Situ Hybridization and Immunohistochemistry

Gene amplification is an important mechanism in the development and progression of cancer. Currently, gene amplification status is generally determined by in situ hybridization (ISH). Multiplex ligation-dependent probe amplification (MLPA) is a PCR-based method that allows copy number detection of up to 50 nucleic acid sequences in one reaction. The aim of the present study was to compare results for HER2, CCND1, MYC and ESR1 gene amplification detected by MLPA with fluorescent in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) as clinically approved methods. Tissue samples of 170 invasive breast cancers were collected. All were ER positive. Tissue samples had previously been tested for HER2 using immunohistochemistry. Amplification of the selected genes were assessed using MLPA, FISH and CISH and results were compared. HER2 MLPA and ISH results were also compared with HER2 immunohistochemistry (IHC) which detects protein overexpression. Amplification of HER2, CCND1, MYC and ESR1 by MLPA were found in 9%, 19%, 20% and 2% of samples, respectively. Amplification of HER2, CCND1, MYC and ESR1 by FISH was noted in 7%, 16%, 16% and 1% of samples, respectively. A high level of concordance was found between MLPA/ FISH (HER2: 88%, CCND1: 88%, MYC: 86%, ESR1: 92%) and MLPA/ CISH (HER2: 84%). Of all IHC 3+ cases, 91% were amplified by MLPA. In IHC 2+ group, 31% were MLPA amplified. In IHC 1+ group, 2% were MLPA amplified. None of the IHC 0 cases were amplified by MLPA. Our results indicate that there is a good correlation between MLPA, IHC and ISH results. Therefore, MLPA can serve as an alternative to ISH for detection of gene amplification.

Cystic apocrine ductal carcinoma in situ with increased EGFR expression, trisomy 7, and associated focal invasion

A 71-year-old woman was admitted to our hospital with a lump in her right breast. Mammography revealed an internal high-density mass in the lower right breast, which was larger than it was 2 years ago. Considering the findings from ultrasonography, computed tomography, and cytology, an intracystic carcinoma could not be ruled out. The patient underwent excisional biopsy, which revealed an apocrine ductal carcinoma in situ (ADCIS) with focal invasive apocrine carcinoma (IAC). The diagnosis was based on morphology and immunohistochemistry (IHC), which was negative for the estrogen and progesterone receptors, and positive for the androgen receptor. Expression of the human epidermal growth factor receptor 2 and the epidermal growth factor receptor (EGFR) received an immunohistochemical score of 2+. Trisomy of chromosome 7, including multiple CEP 7 and EGFR signals, was observed in ADCIS by fluorescence in situ hybridization (FISH). IAC exhibited similar results for IHC and FISH. This is the first reported case showing trisomy 7 resulting in EGFR copy number gain and increased EGFR expression in ADCIS.

Prognostic and predictive value of copy number alterations in invasive breast cancer as determined by multiplex ligation-dependent probe amplification

BACKGROUND

Breast cancer is a leading cause of morbidity and mortality in women worldwide. About 70 % of breast cancers are estrogen receptor (ER) positive. Blocking estrogen action by tamoxifen has been the treatment of choice in ER positive breast cancers for more than 30 years. In the past, several studies have revealed associations between gene copy number alterations and responsiveness to tamoxifen therapy, but so far no single gene copy number alteration could completely explain the response variation observed between individual breast cancer patients. Here, we set out to perform a simultaneous analysis of copy number alterations of several genes involved in the prognosis and response to therapy by multiplex ligation-dependent probe amplification (MLPA).

METHODS

A case-control study was designed encompassing 170 non-metastatic ER positive breast cancer patients (case group = 85, control group = 85). All patients in the control group had received standard adjuvant tamoxifen treatment for 5 years without any evidence of recurrence. Patients in the case group had experienced early recurrences while receiving tamoxifen treatment. 76 % of the patients of the case group and 73 % of the patients of the control group had received anthracycline-based adjuvant chemotherapy. Gene copy number alterations detected by MLPA in both groups were compared.

RESULTS

Amplification of CCND1 (OR = 3.13; 95 % CI = 1.35 to 7.26; p = 0.006) and TOP2A (OR = 3.05; 95 % CI = 1.13 to 8.24; p = 0.022) were significantly more prevalent in the case group, compared to the control group. In a multivariate analysis CCND1 (p = 0.01) and TOP2A (p = 0.041) amplifications remained significant predictors of recurrence.

CONCLUSIONS

Our results indicate that CCND1 amplification may serve as a useful biomarker for hormone responsiveness, and that TOP2A amplification may serve as a useful prognostic biomarker.

EGFR Gene Amplification and Protein Expression in Invasive Ductal Carcinoma of the Breast

Background

The epidermal growth factor receptor (EGFR) is a surrogate marker for basal-like breast cancer. A recent study suggested that EGFR may be used as a target for breast cancer treatment.

Methods

A total of 706 invasive ductal carcinomas (IDC) of the breast were immunophenotyped, and 82 cases with EGFR protein expression were studied for EGFR gene amplification.

Results

EGFR protein was expressed in 121 of 706 IDCs (17.1%); 5.9% were of luminal type, 25.3% of epidermal growth factor receptor 2 (HER-2) type, and 79.3% of basal-like tumors. EGFR gene amplification and high polysomy (fluorescent in situ hybridization [FISH]-positive) were found in 18 of 82 cases (22.0%); 41.2% of the HER-2⁺, EGFR⁺, cytokeratin 5/6^- (CK5/6^-) group, 11.2% of the HER-2^-, EGFR⁺, CK5/6^- group, and 19.1% of the HER-2^-, EGFR⁺, CK5/6⁺ group. FISH-positive cases were detected in 8.3% of the EGFR protein 1⁺ expression cases, 15.9% of 2⁺ expression cases, and 38.5% of 3⁺ expression cases. In group 2, the tumors had a high Ki-67 labeling (>60%), but the patients showed better disease-free survival than those with tumors that co-expressed HER-2 or CK5/6.

Conclusions

EGFR-directed therapy can be considered in breast cancer patients with EGFR protein overexpression and gene amplification, and its therapeutic implication should be determined in HER-2 type breast cancer patients.

EGFR overexpression relates to triple negative profile and poor prognosis in breast cancer patients in Tunisia

BACKGROUND

The prognosis of breast carcinoma is related to a large variety of clinical and pathological factors. Currently, only oestrogen (ER) and progesterone (PR) receptors and human epidermal growth factor receptor 2 (HER2) are used in routine pathological assessment as biomarkers. The aim of this study was to evaluate the prognostic impact of epidermal growth factor receptor (EGFR) expression individually and in combination to classical biomarkers (HER2, ER, and PR), and its relation to tumors with triple negative profile in Tunisian breast carcinoma.

METHODS

Immunohistochemistry was used to estimate the rate expression of these receptors. Univariate and multivariate analyses were used to explore the prognostic significance of EGFR in this study.

RESULTS

The expression rate of EGFR was 28.6%. EGFR expression was inversely correlated to that of ER (P < 0.001). Significant correlations between the expression of EGFR and the high histological Scarff-Bloom-Richardson (SBR) grade (P = 0.038) and also with tumors size (P = 0.041) were observed. The triple negative profile (TN: ER-/PR-/HER2-) was present in 17.3% of cases. EGFR overexpression was positively associated with this clinical aggressive profile (P < 0.001). Survival analysis showed that EGFR expression was associated with poor survival of patients (P = 0.004). In multivariate analysis, EGFR expression (P = 0.035) was found to be independent prognostic factors (significantly correlated to survival).

CONCLUSION

EGFR overexpression was observed in 28.6% of Tunisian breast carcinoma, associated with unfavorable prognosis and with triple negative tumors. Systemically evaluation of EGFR in breast carcinoma could benefit especially to TN subgroup from EGFR targeting agents.

Molecular differences between ductal carcinoma in situ and adjacent invasive breast carcinoma: a multiplex ligation-dependent probe amplification study

Background

Ductal carcinoma in situ (DCIS) accounts for approximately 20% of mammographically detected breast cancers. Although DCIS is generally highly curable, some women with DCIS will develop life-threatening invasive breast cancer, but the determinants of progression to infiltrating ductal cancer (IDC) are largely unknown.

Methods

In the current study, we used multiplex ligation-dependent probe amplification (MLPA), a multiplex PCR-based test, to compare copy numbers of 21 breast cancer related genes between laser-microdissected DCIS and adjacent IDC lesions in 39 patients. Genes included in this study were ESR1, EGFR, FGFR1, ADAM9, IKBKB, PRDM14, MTDH, MYC, CCND1, EMSY, CDH1, TRAF4, CPD, MED1, HER2, CDC6, TOP2A, MAPT, BIRC5, CCNE1 and AURKA.

Results

There were no significant differences in copy number for the 21 genes between DCIS and adjacent IDC. Low/intermediate-grade DCIS showed on average 6 gains/amplifications versus 8 in high-grade DCIS (p = 0.158). Furthermore, alterations of AURKA and CCNE1 were exclusively found in high-grade DCIS, and HER2, PRDM14 and EMSY amplification was more frequent in high-grade DCIS than in low/intermediate-grade DCIS. In contrast, the average number of alterations in low/intermediate and high grade IDC was similar, and although EGFR alterations were exclusively found in high grade IDC compared to low/intermediate-grade IDC, there were generally fewer differences between low/intermediate-grade and high-grade IDC than between low/intermediate-grade and high-grade DCIS.

Conclusion

In conclusion, there were no significant differences in copy number for 21 breast cancer related genes between DCIS and adjacent IDC, indicating that DCIS is genetically as advanced as its invasive counterpart. However, high grade DCIS showed more copy number changes than low/intermediate grade DCIS with specifically involved genes, supporting a model in which different histological grades of DCIS are associated with distinct genomic changes that progress to IDC in different routes. These high grade DCIS specific genes may be potential targets for treatment and/or predict progression.

Electronic supplementary material

The online version of this article (doi:10.1007/s13402-011-0043-7) contains supplementary material, which is available to authorized users.

Prognostic significance of epidermal growth factor receptor and vascular endothelial growth factor receptor in colorectal adenocarcinoma

The purpose of this study was to evaluate the association between the expression of growth factors and the clinicopathological variables of colorectal adenocarcinoma. Immunohistochemistry and fluorescence in situ hybridization (FISH) were used to evaluate the amplification and expression of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), VEGF-D, VEGF receptor (VEGFR)-2, VEGFR-3, transforming growth factor (TGF)-β1, and insulin-like growth factor-1 receptor (IGF-1R) in a tissue microarray of 292 colorectal adenocarcinomas. The expression of EGFR, VEGF, VEGF-D, VEGFR-2 and VEGFR-3 was detected in 5.1%, 10.0%, 6.8%, 5.2%, and 57.2%. EGFR expression was associated with angioinvasion (p < 0.05) and lymph node metastasis (p < 0.005). VEGFR-3 expression was higher in the rectum than in the colon (p < 0.05). VEGF expression correlated with VEGF-D (p < 0.05) and VEGFR-3 (p < 0.005) expression, while VEGF-D expression showed no significant association with VEGFR-2 or VEGFR-3. EGFR amplification was present in 10.6% and was not associated with EGFR protein expression. VEGFR-2 and VEGFR-3 expression levels were related to poor patient survival. Stage, perineural invasion, and lymph node metastasis were independent prognostic factors based on a Cox analysis. VEGFR-2 and VEGFR-3 expression are markers of a poor prognosis in patients with surgically resected colorectal adenocarcinoma, whereas EGFR has a minor influence.

Usefulness of tissue microarrays for assessment of protein expression, gene copy number and mutational status of EGFR in lung adenocarcinoma

Specific inhibitors targeting the epidermal growth factor receptor (EGFR) can increase survival rates in certain lung adenocarcinoma patients with mutations in the EGFR gene. Although such EGFR-targeted therapies have been approved for use, there is no general consensus among surgical pathologists on how the EGFR status should be tested in lung adenocarcinoma tissues and whether the results of immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and mutational analysis by molecular methods correlate. We evaluated the EGFR status in 61 lung adenocarcinomas by IHC (using total and mutant-specific antibodies against EGFR), by FISH analysis on tissue microarrays (TMAs), and by direct sequencing. The results of each method were compared using χ² and κappa statistics. The sensitivity and negative predictive value estimating the presence of abnormal EGFR for each test was calculated. The results show that, with respect to expression patterns and clinicopathological parameters, the total and mutant-specific EGFR detected by immunohistochemistry and FISH analysis on TMAs are valid and are equivalent to conventional methods performed on whole-tissue sections. Abnormal EGFR was detected in 52.4% of patients by IHC, FISH, and sequencing. The best sensitivity (100%) and negative predictive value (100%) was determined by evaluating the EGFR status with all methods. Testing for molecular changes in EGFR using a single test is likely to underestimate the presence of EGFR abnormalities. Taken together, these results demonstrate the high potential of TMAs to test for the major mechanisms of EGFR activation in patients with lung adenocarcinoma.

Molecular profiling of invasive breast cancer by multiplex ligation-dependent probe amplification-based copy number analysis of tumor suppressor and oncogenes

Several oncogenes and tumor-suppressor genes have been shown to be implicated in the development, progression and response to therapy of invasive breast cancer. The phenotypic uniqueness (and thus the heterogeneity of clinical behavior) among patients' tumors may be traceable to the underlying variation in gene copy number of these genes. To obtain a more complete view of gene copy number changes and their relation to phenotype, we analyzed 20 breast cancer-related genes in 104 invasive breast cancers with the use of multiplex ligation-dependent probe amplification (MLPA). We identified MYC gene amplification in 48% of patients, PRDM14 in 34%, topoisomerase IIalpha (TOP2A) in 32%, ADAM9 in 32%, HER2 in 28%, cyclin D1 (CCND1) in 26%, EMSY in 25%, IKBKB in 21%, AURKA in 17%, FGFR1 in 17%, estrogen receptor alpha (ESR1) in 16%, CCNE1 in 12% and EGFR in 9% of patients. There was a significant correlation between the number of amplified genes and the histological grade and mitotic index of the tumor. Gene amplifications of EGFR, CCNE1 and HER2 were negatively associated with estrogen receptor status whereas FGFR1, ADAM9, IKBKB and TOP2A revealed a positive association. Amplifications of ESR1, PRDM14, MYC and HER2 were associated with a high mitotic index, and PRDM14 and HER2 amplifications with high histological grade. MYC amplification was detected more frequently in ductal tumors and high-level MYC amplifications were significantly associated with large tumor size. HER2/MYC, HER2/CCNE1 and EGFR/MYC co-amplified tumors were significantly larger than tumors with either of these amplifications. Gene loss occurred most frequently in E-cadherin (CDH1) (20%) and FGFR1 (10%). In conclusion, MLPA analysis with this 'breast cancer kit' allowed to simultaneously assess copy numbers of 20 important breast cancer genes, providing an overview of the most frequent (co)amplifications as well as interesting phenotypic correlations, and thereby data on the potential importance of these genes in breast cancer.

EGFR and HER-2/neu expression in invasive apocrine carcinoma of the breast

This study was undertaken to investigate epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2)/neu expression in a cohort of apocrine carcinomas of the breast with emphasis on the classification of the breast tumors with apocrine morphology. In total, 55 breast carcinomas morphologically diagnosed as apocrine were evaluated for the steroid receptor expression profile characteristic of normal apocrine epithelium (androgen receptor positive/estrogen receptor (ER) negative/progesterone receptor (PR) negative), and for the expression of EGFR and Her-2/neu proteins, and the copy number ratios of the genes EGFR/CEP7 and HER-2/CEP17. On the basis of the results of steroid receptors expression, 38 (69%) cases were classified as pure apocrine carcinoma (androgen receptor positive/ER negative/PR negative), whereas 17 (31%) were re-classified as apocrine-like carcinomas because they did not have the characteristic steroid receptor expression profile. Her-2/neu overexpression was observed in 54% of the cases (57% pure apocrine carcinomas vs 47% apocrine-like carcinomas). HER-2/neu gene amplification was demonstrated in 52% of all cases (54% pure apocrine carcinomas vs 46% apocrine-like carcinomas). EGFR protein (scores 1 to 3+) was detected in 62% of all cases and was expressed in a higher proportion of pure apocrine carcinomas than in the apocrine-like carcinomas group (76 vs 29%, P=0.006). In the pure apocrine carcinoma group, Her-2/neu and EGFR protein expression were inversely correlated (P=0.006, r=-0.499). EGFR gene amplification was observed in two pure apocrine carcinomas and one apocrine-like carcinoma. Polysomy 7 was commonly present in pure apocrine carcinomas (61 vs 27% of apocrine-like carcinomas; P=0.083) and showed a weak positive correlation with EGFR protein expression (P=0.025, r=0.326). Our study showed that apocrine breast carcinomas are molecularly diverse group of carcinomas. Strictly defined pure apocrine carcinomas are either HER-2-overexpressing breast carcinomas or triple-negative breast carcinomas, whereas apocrine-like carcinomas predominantly belong to the luminal phenotype. Pure apocrine carcinomas show consistent overexpression of either EGFR or HER-2/neu, which could have significant therapeutic implications.

Immunohistochemical expression of Epidermal Growth Factor Receptor (EGFR) in canine mammary tissues

Epidermal Growth Factor Receptor (EGFR) has been extensively studied in human breast cancer; however, systematic studies of EGFR protein expression in canine mammary gland tumours are lacking. Therefore, we evaluated its immunohistochemical expression in a series of 136 canine mammary tumours and representative areas of adjacent normal and hyperplastic mammary tissue and investigated a possible correlation between EGFR overexpression and several clinicopathological parameters and survival. In normal and hyperplastic canine mammary glands, EGFR expression was consistently observed in myoepithelial cells, with luminal cells usually negative. In tumour tissues, EGFR overexpression was found in 9 benign (19.6%) and 38 malignant (42.2%) lesions, with EGFR positivity significantly related with malignancy. Besides animal age and tumour size, there were no significant associations between other clinicopathological parameters and EGFR overexpression. On survival analysis, tumours with EGFR overexpression showed a reduced disease-free and overall survival; however these associations failed to reach statistically significant levels.

EGFR, pMAPK, pAkt and PTEN status by immunohistochemistry: correlation with clinical outcome in HER2-positive metastatic breast cancer patients treated with trastuzumab

BACKGROUND

In an attempt to identify markers of resistance to trastuzumab, we evaluated both the profiling of human epidermal growth factor receptor 2 (HER2)-positive tumor cells measuring the relative levels of EGFR, pMAPK, pAkt and PTEN and their correlations with clinical outcome in HER2-positive metastatic breast cancer patients treated with trastuzumab.

PATIENTS AND METHODS

Tumor tissues for this retrospective analysis were available from 45 out of 76 patients with metastatic breast cancer treated from April 1999 to March 2006 with trastuzumab-based therapy at our Institution. Evaluations of EGFR, pMAPK, pAkt and PTEN status by immunohistochemistry (IHC) were carried out on all 45 tissue samples and their correlations with response to trastuzumab, incidence of central nervous system (CNS) metastases, time to progression (TTP), overall survival from diagnosis of breast cancer (OS1), from diagnosis of metastatic disease (OS2) and from the start of trastuzumab (OS3) were analyzed.

RESULTS

We observed that TTP (P = 0.001) and median OS2 and OS3 were significantly longer in patients responsive to trastuzumab-based regimen compared with nonresponsive patients. EGFR, pMAPK, pAkt and PTEN status by IHC were not significantly associated with response to trastuzumab, TTP, overall survival (OS1, OS2, OS3) and CNS metastases incidence. A trend for shorter OS3 was observed for pMAPK-positive patients compared with pMAPK-negative patients (22.8 versus 31.2 months; P = 0.076). Median OS1 resulted shorter in 22 pAkt-positive patients (69.8 months) compared with 23 pAkt-negative patients (108.2 months); P = 0.091. It is likely that high expression of pMAPK (pMAPK-positive status) or pAkt (pAkt-positive status) could identify a subgroup of HER2-positive tumors with high activity of proliferation and survival pathways and with resistance to trastuzumab.

CONCLUSIONS

In HER2-positive metastatic breast cancers, EGFR, pMAPK, pAkt and PTEN status evaluated by IHC was not significantly associated with response to trastuzumab, TTP, OS and CNS metastases incidence. However, HER2 status determined by IHC and/or FISH assays may not be sufficient to predict response to trastuzumab-based therapy.

The UPS: a promising target for breast cancer treatment

During the past decade, progress in endocrine therapy and the use of trastuzumab has significantly contributed to the decline in breast cancer mortality for hormone receptor-positive and ERBB2 (HER2)-positive cases, respectively. As a result of these advances, a breast cancer cluster with poor prognosis that is negative for the estrogen receptor (ESR1), the progesterone receptor (PRGR) and ERBB2 (triple negative) has come to the forefront of medical therapeutic attention. DNA microarray analyses have revealed that this cluster is phenotypically most like the basal-like breast cancer that is caused by deficiencies in the BRCA1 pathways. To gain further improvements in breast cancer survival, new types of drugs might be required, and small molecules targeting the ubiquitin proteasome system have moved into the spotlight. The success of bortezomib in the treatment of multiple myeloma has sent encouraging signals that proteasome inhibitors could be used to treat other types of cancers. In addition, ubiquitin E3s involved in ESR1, ERBB2 or BRCA1 pathways could be ideal targets for therapeutic intervention. This review summarizes the ubiquitin proteasome pathways related to these proteins and discusses the possibility of new drugs for the treatment of breast cancers. PUBLICATION HISTORY : Republished from Current BioData's Targeted Proteins database (TPdb; http://www.targetedproteinsdb.com).

Short-term outcome of primary operated early breast cancer by hormone and HER-2 receptors

INTRODUCTION

Prognostic subgroup classification of operable breast cancers using cDNA clustering of breast cancer-related genes resembles the classification based on the combined immunohistochemical (IHC) expression of the hormone and HER-2 receptors. We here report the short-term disease-free interval (DFI) of operable breast cancers by their joint hormone receptor/HER-2 phenotype.

PATIENTS AND METHODS

Short-term follow-up (FU) of a prospective cohort of 1,958 breast-cancer patients primary operated at our institution between 2000 and 2005. Receptors were evaluated using IHC. Steroid receptors were considered positive for any nuclear staining; HER-2 for strong (3+) membrane staining or positive fluorescence in situ hybridization (FISH). Kaplan-Meier (KM) DFI curves were calculated for any relapse defined as a local, regional, contralateral, or distant breast cancer event for the six predefined breast cancer subgroups: ER + PR + HER-2 - (PPN), ER + PR - HER-2 - (PNN), ER + PR + HER-2 + (PPP), ER - PR - HER-2 - (NNN), ER - PR - HER-2 + (NNP), and ER + PR - HER-2 + (PNP). P-values were calculated for comparison of the six different survival curves using two possible adaptations for multiple testing. A multivariate model for the receptors predicting DFI did incorporate local and systemic adjuvant therapy.

RESULTS

Median patient age was 57 years (ranges 26-96) and median FU was 3.35 years. Overall, DFI at median FU was 91%; 94% for PPN, 89% for PNN, 86% for NNN, 81% for PPP, 80% for PNP, and 76% for NNP cases. Some receptor subgroups had a significantly better DFI than others based on multiple testing, especially when the PPN group was compared against the four most frequent subtypes. The multivariate model with local and systemic adjuvant therapy confirmed the prognostic value of ER, PR, and HER-2 for short-term DFI.

CONCLUSION

It is possible to distinguish short-term prognostic breast cancer subgroups only on the basis of ER, PR, and HER-2 even when stratified for local and systemic adjuvant therapy. While gene expression profiles based on microarray data of over hundreds of genes will probably teach us much about breast cancer biology, heterogeneity, and prognosis, we emphasize the important short-term prognostic value of currently used IHC markers for ER, PR, and HER-2.

Progressive loss of epidermal growth factor receptor in a subpopulation of breast cancers: implications in target-directed therapeutics

Understanding the molecular etiology and heterogeneity of disease has a direct effect on cancer therapeutics. To identify novel molecular changes associated with breast cancer progression, we conducted phosphoproteomics of the MCF10AT model comprising isogenic, ErbB2- and ErbB3-positive, xenograft-derived cell lines that mimic different stages of breast cancer. Using in vitro animal model and clinical breast samples, our study revealed a marked reduction of epidermal growth factor receptor (EGFR) expression with breast cancer progression. Such diminution of EGFR expression was associated with increased resistance to Gefitinib/Iressa in vitro. Fluorescence in situ hybridization showed that loss of EGFR gene copy number was one of the key mechanisms behind the low/null expression of EGFR in clinical breast tumors. Statistical analysis on the immunohistochemistry data of EGFR expression from 93 matched normal and breast tumor samples showed that (a) diminished EGFR expression could be detected as early as in the preneoplastic lesion (ductal carcinoma in situ) and this culminated in invasive carcinomas; (b) EGFR expression levels could distinguish between normal tissue versus carcinoma in situ and invasive carcinoma with high statistical significance (P < 0.001, n = 81). However, no significant correlation of EGFR expression with disease-free survival and overall survival was observed. This is the first time EGFR expression has been tracked meaningfully and developmentally from the normal condition through disease progression using in vitro, xenograft, and matched normal and tumor samples. Thus, our study provides a new insight into the role of EGFR in breast cancer development. Although no value of EGFR expression in prognosis was found, our findings are likely to have implications in the design of clinical trials targeting the EGFR family of proteins in breast cancer.