HER-2 protein concentrations in breast cancer cells increase before immunohistochemical and fluorescence in situ hybridization analysis turn positive

Loss of Human Epidermal Receptor 2 Expression in Formalin-Fixed Paraffin-Embedded Breast Cancer Samples and the Rescuing Effect of Enhanced Antigen Retrieval and Signal Amplification

As an important therapeutic target in breast cancer, HER2 expression assessed by immunohistochemistry plays a critical role in breast cancer treatment. Recent advances in HER2 antibody-drug conjugate therapy have enabled patients with HER2-low expression breast cancer to benefit from the drugs. However, it is not known whether the HER2-low expression in breast cancer FFPE blocks would be lost as storage time increased. In this study, we aimed to assess the loss of HER2 antigenicity in stored FFPE blocks of breast cancer and the rescue effect of modifying the protocol of antigen staining. We selected archived HER2-low breast cancer FFPE blocks with stored time ranging from 1 year to over 15 years and re-detected the expression of HER2. Our study showed that HER2 antigenicity loss increased with storage time and could cause false negativity in HER2-low detection. Moreover, we showed that by either increasing the antigen retrieval time or applying the tyramide signal amplification (TSA) kit, the HER2 signal can be rescued and detected in about half of the cases with HER2-low loss without causing false positivity.

High inter-laboratory variability in the assessment of HER2-low breast cancer: a national registry study on 50,714 Danish patients

BACKGROUND

Considering the recent advancements in the treatment of breast cancer with low expression of human epidermal growth factor receptor 2 (HER2), we aimed to examine inter-laboratory variability in the assessment of HER2-low breast cancer across all Danish pathology departments.

METHODS

From the Danish Breast Cancer Group, we obtained data on all women diagnosed with primary invasive breast cancer in 2007-2019 who were subsequently assigned for curatively intended treatment.

RESULTS

Of 50,714 patients, HER2 score and status were recorded for 48,382, among whom 59.2% belonged to the HER2-low group (score 1+ or 2+ without gene amplification), 26.8% had a HER2 score of 0, and 14.0% were HER2 positive. The proportion of HER2-low cases ranged from 46.3 to 71.8% among pathology departments (P < 0.0001) and from 49.3 to 65.6% over the years (P < 0.0001). In comparison, HER2 positivity rates ranged from 11.8 to 17.2% among departments (P < 0.0001) and from 12.6 to 15.7% over the years (P = 0.005). In the eight departments with the highest number of patients, variability in HER2-low cases increased from 2011 to 2019, although the same immunohistochemical assay was used. By multivariable logistic regression, the examining department was significantly related to both HER2 score 0 and HER2 positivity (P < 0.0001) but showed greater dispersion in odds ratios in the former case (range 0.25-1.41 vs. 0.84-1.27).

CONCLUSIONS

Our data showed high inter-laboratory variability in the assessment of HER2-low breast cancer. The findings cast doubt on whether the current test method for HER2 is robust and reliable enough to select HER2-low patients for HER2-targeted treatment in daily clinical practice.

Diagnostic value of serum HER2 levels in breast cancer: a systematic review and meta-analysis

BACKGROUND

Measurement of serum human epidermal growth factor receptor-2 (HER-2/neu) levels might play an essential role as a diagnostic/screening marker for the early selection of therapeutic approaches and predict prognosis in breast cancer patients. We aimed to undertake a systematic review and meta-analysis focusing on the diagnostic/screening value of serum HER-2 levels in comparison to routine methods.

METHODS

We performed a systematic search via PubMed, Scopus, Cochrane-Library, and Web of Science databases for human diagnostic studies reporting the levels of serum HER-2 in breast cancer patients, which was confirmed using the histopathological examination. Meta-analyses were carried out for sensitivity, specificity, accuracy, area under the ROC curve (AUC), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR).

RESULTS

Fourteen studies entered into this investigation. The meta-analysis indicated the low sensitivity for serum HER2 levels (Sensitivity: 53.05, 95%CI 40.82-65.28), but reasonable specificity of 79.27 (95%CI 73.02-85.51), accuracy of 72.06 (95%CI 67.04-77.08) and AUC of 0.79 (95%CI 0.66-0.92). We also found a significant differences for PPV (PPV: 56.18, 95%CI 44.16-68.20), NPV (NPV: 76.93, 95%CI 69.56-84.31), PLR (PLR: 2.10, 95%CI 1.69-2.50) and NLR (NLR: 0.58, 95%CI 0.44-0.71).

CONCLUSION

Our findings revealed that although serum HER-2 levels showed low se nsitivity for breast cancer diagnosis, its specificity, accuracy and AUC were reasonable. Hence, it seems that the measurement of serum HER-2 levels can play a significant role as a verification test for initial negative screening test results, especially in low-income regions due to its cost-effectiveness and ease of implementation.

Photochemical activation of the recombinant HER2-targeted fusion toxin MH3-B1/rGel; Impact of HER2 expression on treatment outcome

HER2 is overexpressed in 20-30% of breast tumors and is associated with aggressiveness and increased risk of recurrence and death. The HER2 protein is internalized as a part of its activity, and may therefore be utilized as a target for the specific intracellular delivery of drugs. Photochemical internalization (PCI) is a novel technology now undergoing clinical evaluation for its ability to improve the release into the cytosol of drugs entrapped in the endo/lysosomal compartment. PCI employs an amphiphilic photosensitizer which localizes in the membranes of endo/lysosomes. Subsequent light exposure (visible light) causes destabilization of the endo/lysosomal membranes. PCI has been proven highly effective for improving the cytosolic delivery of targeted toxins based on type I ribosome inactivating protein toxins such as gelonin. We examined the impact of the level of target antigen expression on PCI efficacy. Four human breast cancer cell lines (MDA-MB-231, BT-20, Zr-75-1 and SK-BR-3) covering a wide range of HER2 expression were included in the present study. PCI of the HER2-targeted fusion toxin MH3-B1/rGel was found to be highly effective in all four cell lines. The increase in PCI-mediated efficacy was not directly correlated with the cellular levels of HER2 as assessed by western blots, the overall uptake of MH3-B1/rGel as measured by flow cytometry, the amount of MH3-B1/rGel localized to endo/lysosomes assessed by confocal microscopy or the cell sensitivity to the photochemical treatment itself (photosensitizer and light without MH3-B1/rGel). However, correcting the PCI efficacy for the baseline cellular sensitivity to rGel revealed a linear correlation (R(2)=0.80) with HER2 expression. The present report therefore concludes the cellular sensitivity to the toxin as an important parameter for PCI efficacy and also indicates PCI of a HER2-targeted fusion toxin as an attractive treatment alternative for breast cancer patients with both HER2-low and -high expression.

Predicting brain metastases of breast cancer based on serum S100B and serum HER2

Brain metastases are a major cause of morbidity and mortality in breast cancer. The aim of the current study was to evaluate the prediction of brain metastases based on serum S100B and human epidermal growth factor receptor 2 (HER2). A total of 107 breast cancer patients were included in the current study from two prospective cohort studies with either elevated serum HER2 levels >15 ng/ml or brain metastases verified by magnetic resonance imaging (MRI) or computer tomography (CT). Following the exclusion of six patients, the remaining 101 patients were divided into two groups: Group 0 (n=55), patients with normal MRI results; and group 1 (n=46), patients with brain metastases. The levels of serum S100B and HER2 in the two groups were analyzed prior to MRI or CT of the brain, and no significant differences were identified in the serum HER2 (P=0.060) or S100B levels (P=0.623) between the groups. The univariate analysis of prognostic factors for brain metastases showed a significant correlation with systemic disease (P<0.001), axillary lymph node metastases (P=0.001) and serum HER2 >30 ng/ml (P=0.002). Only systemic disease (P<0.001) remained statistically significant in the multivariate analysis. In conclusion, serum levels of S100B and HER2 did not predict the risk of brain metastases. In the multivariate analysis, brain metastases were only found to correlate with systemic disease. However, in the univariate analysis, serum HER2 levels >30 ng/ml were identified to correlate with increased risk of brain metastases, which calls for further investigation.

Prognostic impact of placenta growth factor and vascular endothelial growth factor A in patients with breast cancer

Placenta growth factor (PlGF) and vascular endothelial growth factor A (VEGF-A) are angiogenic growth factors interacting competitively with the same receptors. VEGF-A is essential in both normal and pathologic conditions, but the functions of PlGF seem to be restricted to pathologic conditions such as ischemic heart disease, arthritis and tumor growth. Angiogenesis is a complex process with several growth factors involved. Because PlGF modulates VEGF-A responses, we investigated their mutual relationship and impact on breast cancer prognosis. Quantitative PlGF and VEGF-A levels were measured in 229 tumor tissue specimen from primarily operated patients with unilateral breast cancer. Non-malignant breast tissue was also dissected near the tumor and quantitative measurements were available for 211 patients. PlGF and VEGF-A protein levels in homogenized tissue lysates were analyzed using the Luminex system. We found significantly higher median levels of PlGF and VEGF-A in tumor tissue compared to non-malignant tissue (PlGF: 69.8 vs. 31.4 pg/mg, p < 0.001 and VEGF-A: 1148.2 vs. 163.5 pg/mg, p < 0.001). PlGF and VEGF-A were correlated in both malignant tissue (r = 0.41, p < 0.001) and in non-malignant tissue (r = 0.69, p < 0.001). The proportion of node positive patients was higher with high PlGF expression (61.4%) than with low PlGF expression (45.6%) in tumor tissue, p = 0.024. High levels of PlGF and VEGF-A in tumor tissue were associated with significant shorter recurrence-free survival (RFS) in both univariate analysis (PlGF: p = 0.023; VEGF-A: p = 0.047) and in multivariate analysis (PlGF: p = 0.026; VEGF-A: p = 0.036). Neither PlGF nor VEGF-A expression in non-malignant tissue were predictors for RFS. In conclusion, our results support the mutual relationship between PlGF and VEGF-A and encourage further investigations as prognostic markers in breast cancer patients.

HER1-4 protein concentrations in normal breast tissue from breast cancer patients are expressed by the same profile as in the malignant tissue

BACKGROUND

The epidermal growth factor receptor HER2 is overexpressed or amplified in 25%-30% of patients with breast cancer. The mechanism behind HER2 amplification is unknown, but may be a patho-physiological phenomenon caused by continuous stimulation and activation of the HER1-4 system. We have mapped the protein concentrations of HER1-4 in breast cancer tissue, autologous reference tissue, normal breast tissue and serum samples, to see whether non-cancer cells from these patients express a protein profile indicating general activation.

METHODS

Tissue samples from malignant and adjacent normal breast tissue (autologous reference tissue) were collected from 118 women consecutively admitted for surgical treatment of breast cancer. In addition, 26 samples of normal breast tissue were collected from healthy women having breast reduction surgery. The tissue samples were homogenized and the proteins extracted. The tissue and serum concentrations of HER1-4 were determined quantitatively using a commercially available enzyme linked immunosorbent assay (ELISA) method.

RESULTS

HER1 was down regulated in cancer tissue when compared to autologous reference tissue (p=8 x 10(-6)), while HER2 (p<10(-7)) and HER3 (p=3 x 10(-5)) were up regulated. Comparing autologous reference tissue with normal tissue showed down regulation of HER1 (p=0.122) and up regulation of HER2 (p=10(-6)), HER3 (p<10(-7)) and HER4 (p<10(-7)). Furthermore, we observed that correlations between the receptor combinations HER1-2, HER1-3 and HER1-4 were maintained from normal breast tissue to autologous reference breast tissue, but were lost in cancer tissue.

CONCLUSIONS

We suggest that these findings indicate that breast cancer is a systemic disease where the HER1-4 system in autologous reference tissue is continuously activated, thus favoring the subsequent development of cancer.

Inorganic nanoparticles for predictive oncology of breast cancer

Nanoparticles (NPs) and nanosized objects are being incorporated rapidly into clinical medicine and particularly into the field of medical oncology, including breast cancer. A number of novel methods for breast cancer diagnosis and treatment, which are based on NPs and other nanodevices, are now available for translation into clinical practice. Computer tomography and MRI with iron-based magnetic NPs are promising methods for radiological detection of cancers. Semiconductor fluorescent NPs (quantum dots) are being developed for simultaneous detection and localization of multiple breast cancer biomarkers, enabling the personalization of therapeutic regimens for each patient. Additionally, inorganic NPs can be conjugated with tumor-specific ligands and used for tumor-selective delivery of chemotherapeutic or hormonal agents. NPs bearing tumor-targeted antibodies and oligonucleotides for anticancer gene therapy are a novel and rapidly developing therapeutic approach in oncology. Nab-paclitaxel and liposomal anthracyclines are US FDA-approved NP-based drug-delivery systems that have demonstrated at least equivalent efficacy and decreased toxicity compared with conventional chemotherapeutic agents used in the treatment of breast cancer. This review focuses on recent applications of NPs into predictive oncology of breast cancer with an emphasis placed on the role of inorganic nanosized objects in the diagnosis and treatment of this malignancy.

The prognostic importance of triple negative breast carcinoma

There is a current debate on whether triple negative breast carcinomas (estrogen receptor--ER-negative, progesterone receptor--PR-negative and HER2-negative) have a poor prognosis. Our aim in this retrospective study was to determine whether triple negative feature is a prognostic factor for disease-free survival (DFS) in 322 breast carcinoma patients, of whom 80 (24.8%) had triple negative tumor histology. In the multivariate analysis, tumor subgroup (triple vs non-triple, p<0.0001; hazard ratio [HR], 4.2; 95% confidence interval [95%CI], 2.2-8.2) was a significant factor related to relapse, in addition to number of metastatic nodes (>4 vs <or=4, p=0.04; HR, 1.6; 95%CI, 1.2-2.4), lymphatic vascular invasion (yes vs no, p=0.002; HR, 2.0; 95%CI, 1.3-3.1) and HER2 (positive vs negative, p<0.0001; HR, 5.9; 95%CI, 3.0-10.0). This result indicated that patients with triple negative histology had a poor disease-free survival and this histology was an independent significant prognostic factor for DFS.

Confocal microscopy and molecular-specific optical contrast agents for the detection of oral neoplasia

Using current clinical diagnostic techniques, it is difficult to visualize tumor morphology and architecture at the cellular level, which is necessary for diagnostic localization of pathologic lesions. Optical imaging techniques have the potential to address this clinical need by providing real-time, sub-cellular resolution images. This paper describes the use of dual mode confocal microscopy and optical molecular-specific contrast agents to image tissue architecture, cellular morphology, and sub-cellular molecular features of normal and neoplastic oral tissues. Fresh tissue slices were prepared from 33 biopsies of clinically normal and abnormal oral mucosa obtained from 14 patients. Reflectance confocal images were acquired after the application of 6% acetic acid, and fluorescence confocal images were acquired after the application of a fluorescence contrast agent targeting the epidermal growth factor receptor (EGFR). The dual imaging modes provided images similar to light microscopy of hematoxylin and eosin and immunohistochemistry staining, but from thick fresh tissue slices. Reflectance images provided information on the architecture of the tissue and the cellular morphology. The nuclear-to-cytoplasmic (N/C) ratio from the reflectance images was at least 7.5 times greater for the carcinoma than the corresponding normal samples, except for one case of highly keratinized carcinoma. Separation of carcinoma from normal and mild dysplasia was achieved using this ratio (p<0.01). Fluorescence images of EGFR expression yielded a mean fluorescence labeling intensity (FLI) that was at least 2.7 times higher for severe dysplasia and carcinoma samples than for the corresponding normal sample, and could be used to distinguish carcinoma from normal and mild dysplasia (p<0.01). Analyzed together, the N/C ratio and the mean FLI may improve the ability to distinguish carcinoma from normal squamous epithelium.