HER2 testing in breast cancer: an overview of current techniques and recent developments

HER2 targeted therapy in colorectal Cancer: Current landscape and future directions

Colorectal cancer (CRC) is one of the most common causes of tumor-related deaths globally. Despite recent improvements in the comprehensive therapy of malignancy, metastatic CRC continues to have a poor prognosis. Human epidermal growth factor receptor 2 (HER2) is an established oncogenic driver, which is successfully targeted for breast and gastric cancers. Approximately 5% of CRC patients carry somatic HER2 mutations or gene amplification. In 2019, the U.S. Food and Drug Administration have approved trastuzumab and pertuzumab in combination with chemotherapy for the treatment of HER2-positive metastatic CRC. This approval marked a significant milestone in the treatment of CRC, as HER2-positive patients now have access to targeted therapies that can improve their outcomes. Yet, assessment for HER2 overexpression/ amplification in CRC has not been standardized. The resistance mechanisms to anti-HER2 therapy have been not clearly investigated in CRC. Although many unknowns remain, an improved understanding of these anti-HER2 agents will be essential for advanced CRC. In this review, we provide an overview of the role of HER2 in CRC as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target, as well as the current progress and challenges in the field.

Detection of ERBB2 and CEN17 signals in fluorescent in situ hybridization and dual in situ hybridization for guiding breast cancer HER2 target therapy

The overexpression of the human epidermal growth factor receptor 2 (HER2) is a predictive biomarker in therapeutic effects for metastatic breast cancer. Accurate HER2 testing is critical for determining the most suitable treatment for patients. Fluorescent in situ hybridization (FISH) and dual in situ hybridization (DISH) have been recognized as FDA-approved methods to determine HER2 overexpression. However, analysis of HER2 overexpression is challenging. Firstly, the boundaries of cells are often unclear and blurry, with large variations in cell shapes and signals, making it challenging to identify the precise areas of HER2-related cells. Secondly, the use of sparsely labeled data, where some unlabeled HER2-related cells are classified as background, can significantly confuse fully supervised AI learning and result in unsatisfactory model outcomes. In this study, we present a weakly supervised Cascade R-CNN (W-CRCNN) model to automatically detect HER2 overexpression in HER2 DISH and FISH images acquired from clinical breast cancer samples. The experimental results demonstrate that the proposed W-CRCNN achieves excellent results in identification of HER2 amplification in three datasets, including two DISH datasets and a FISH dataset. For the FISH dataset, the proposed W-CRCNN achieves an accuracy of 0.970±0.022, precision of 0.974±0.028, recall of 0.917±0.065, F1-score of 0.943±0.042 and Jaccard Index of 0.899±0.073. For DISH datasets, the proposed W-CRCNN achieves an accuracy of 0.971±0.024, precision of 0.969±0.015, recall of 0.925±0.020, F1-score of 0.947±0.036 and Jaccard Index of 0.884±0.103 for dataset 1, and an accuracy of 0.978±0.011, precision of 0.975±0.011, recall of 0.918±0.038, F1-score of 0.946±0.030 and Jaccard Index of 0.884±0.052 for dataset 2, respectively. In comparison with the benchmark methods, the proposed W-CRCNN significantly outperforms all the benchmark approaches in identification of HER2 overexpression in FISH and DISH datasets (p<0.05). With the high degree of accuracy, precision and recall , the results show that the proposed method in DISH analysis for assessment of HER2 overexpression in breast cancer patients has significant potential to assist precision medicine.

The effect of an alternative chromosome 17 probe on fluorescence in situ hybridization for the assessment of HER2 amplification in invasive breast cancer

Fluorescent in situ hybridization (FISH) is commonly used to determine the ratio of human epidermal growth factor receptor 2 (HER2) to centromere enumeration probe for chromosome 17 (CEP17), which further determines HER2 gene status in breast cancer. However, due to copy number alteration in CEP17, inaccurate diagnoses can occur. The current study was performed to investigate the diagnostic value of an alternative CEP17 reference probe for HER2 status in invasive breast cancer. A higher-order repeat in the centromeric region of chromosome 17 was identified and an alternative probe (SCEP17) was subsequently prepared. Karyotype analysis of peripheral blood was used to detect SCEP17 probe specificity. Using a HER2/CEP17 probe, karyotype analysis revealed two strong green signals at the centromere of chromosome 17 and one weaker signal at the other centromere. However, two strong hybridization signals at the centromere of chromosome 17 were observed when the HER2/SCEP17 probe was used. In the 425 patients with invasive breast cancer, no statistical difference was observed between HER2/SCEP17 and HER2/CEP17 when detecting HER2 gene amplification (P=0.157). However, in terms of copy number, the SCEP17 probe exhibited a reduced number compared with the conventional CEP17 probe (P<0.001). In conclusion, the HER2/SCEP17 probe may lead to increased accuracy HER2 status assessment in invasive breast cancer. However, a further large-scale and prospective clinical trial is required for confirmation of the potential benefits of using the HER2/SCEP17 probe.

Correlation Between HER-2 Gene Amplification or Protein Expression and Clinical Pathological Features of Breast Cancer

OBJECTIVE

The incidence of breast cancer in females is gradually increasing. Expression of HER-2 gene and protein is critical for predicting the prognosis of breast cancer. This study examined amplification of HER-2 gene and protein expression in breast cancer patients to analyze their correlation with clinical and pathological features.

MATERIALS AND METHODS

Specimens of breast gland tissues were collected from breast cancer patients for measuring HER-2 protein expression by immunohistochemistry (IHC) method. Fluorescent in situ hybridization (FISH) measured HER-2 gene amplification. The consistency of HER-2 protein and gene expression was analyzed in addition to their correlation with clinical and pathological features of patients.

RESULTS

Thirty-six percent patients showed negative expression of HER-2 protein, and 9%, 32%, and 23% of them had positive expression to different levels (+, ++, and +++). Forty percent patients were positive for HER-2 gene amplification, including 3, 21, and 14 cases of (+), (++), and (+++) patients. Expression of HER-2 protein was highly correlated with HER-2 gene amplification (r = 1.262; p < 0.05). Both parameters were correlated with tumor size, differentiation grade, lymph node metastasis, and TNM stage (p < 0.05).

CONCLUSIONS

Combined assay of IHC and FISH for detecting HER-2 protein or gene amplification in breast cancer tissues showed their correlation with tumor size, differentiation grade, lymph node metastasis, and TNM stage.

The prognostic value of regulatory T cells infiltration in HER2-enriched breast cancer microenvironment

Breast cancer represents a complex and heterogeneous disease that comprises distinct disease conditions, histological features, and clinical outcome. Since many years, it has been demonstrated as an association between HER2 amplification and poor prognosis, because its overexpression is associated with an aggressive phenotype of breast tumor cells. A significant proportion of cases have developed resistance to the current therapies available. Consequently, new prognostic markers are urgently needed to identify patients who are at the highest risk for developing metastases. During the past decade, new insights provided valuable knowledge regarding mechanisms underlying the dynamic interplayed between immune cells and tumor progression. It has been shown that the presence of a lymphocytic infiltrate, particularly of regulatory T cells, in cancer tissue, is associated with clinical outcome promoting rather than inhibiting cancer development and progression. It has been also verified that the clinical value of lymphocytic infiltration in breast cancers could be subtype-dependent, including the HER2-enriched subtype. In this context, this work summarizes proposed to discuss the prognostic value of regulatory T cell infiltration in microenvironment of HER2-enriched breast cancer.

FGF19 genetic amplification as a potential therapeutic target in lung squamous cell carcinomas

Background

Although FGF19 gene aberrations are associated with carcinogenesis and progression in human cancers, the roles of FGF19 genetic amplification and expression in Chinese patients with lung squamous cell carcinoma (LSCC) and FGF19 amplification as a potential therapeutic target for LSCC are not well understood.

Methods

Fluorescence in situ hybridization analysis and quantitative real‐time‐PCR was used to detect FGF19 genetic amplification and FGF19 messenger RNA expression in LSCC tumor and paired adjacent samples. Small interfering RNA and short hairpin RNA were used to knockdown FGF19 in vitro and in vivo.

Results

FGF19 amplification was identified in a subset of LSCC patients (37.5%, 15/40), and upregulation of FGF19 expression was found in 60% (24/40) of tumor tissues compared to adjacent non‐tumorous tissues. Correlation analysis with clinicopathologic parameters showed that FGF19 upregulation was significantly associated with heavy smoking. Small interfering RNA knockdown of FGF19 led to the significant inhibition of cell growth and induced apoptosis in LSCC cells carrying the amplified FGF19 gene, but these effects was not observed in non‐amplified LSCC cells. Interfering FGF19 expression with short hairpin RNA also resulted in tumor growth inhibition and induced apoptosis in LSCC xenografts with amplified FGF19 in tumor cells.

Conclusion

Our results suggested that FGF19 signaling activation is required for cell growth and survival of FGF19 amplified LSCC cells, both in vitro and in vivo. Intervention of FGF19 activation could be a potential therapeutic strategy for LSCC patients with FGF19 amplification.

A molecular pathology method for sequential fluorescence in situ hybridization for multi-gene analysis at the single-cell level

Multi-gene detection at the single-cell level is desirable to enable more precise genotyping of heterogeneous hematology and oncology samples. This study aimed to establish a single-cell multi-gene fluorescence in situ hybridization (FISH) method for use in molecular pathology analyses. Five fluorochromes were used to label different FISH gene probes, and 5 genes were detected using a five-color FISH protocol. After the first hybridization, the previous FISH probe set was stripped, and a second set of five-color FISH probes was used for rehybridization. After each hybridization, the fluorescence signals were recorded in 6 fluorescence filter channels that included DAPI, Spectrum Green^™, Cy3^™ v1, Texas Red, Cy5, and PF-415. A digital automatic relocation procedure was used to ensure that exactly the same microscopic field was studied in each stripping and hybridization cycle. By using this sequential stripping and rehybridization strategy, up to 20 genes can be detected within a single nucleus. In conclusion, a practical molecular pathology method was developed for analyzing multiple genes at the single-cell level.

The Clinicopathologic and Prognostic Value of Altered Chromosome 17 Centromere Copy Number in HER2 Fish Equivocal Breast Carcinomas

Chromosome 17 centromere (CEP17) gain is frequently observed in breast cancer by fluorescence in situ hybridization (FISH). To address the biologic characteristics and clinical significance of CEP17 gain in a large population of breast cancer patients, we performed FISH on a series of 770 breast cancer tissues to evaluate the status of human epidermal growth factor receptor 2 (HER2) gene and CEP17 by immunohistochemistry (IHC) and FISH. Among the 770 specimens, 184 cases showed CEP17 gain (23.9%). Histological grade, nodal status, HER2 by IHC, Ki 67 index, and p53 expression were significantly different between CEP17 gain tumors and HER2-positive tumors. In contrast with HER2-negative tumors, CEP17 gain tumors showed higher histological grade, higher HER2 score by IHC, and higher Ki 67 index. The patients with CEP17 gain tumors had an intermediate survival between HER2-negative and HER2-positive patients. By comparison to HER2-negative and HER2-positive patients, survival in luminal B patients with CEP17 gain tumors also fell in between. In conclusion, CEP17 gain tumors show specific differences compared with HER2-negative and HER2-positive tumors in clinical parameters and prognosis.

The current state of molecular cytogenetics in cancer diagnosis

Cytogenetics and molecular cytogenetics are and will continue to be indispensable tools in cancer diagnostics. Leukemia and lymphoma diagnostics are still emphases of routine (molecular) cytogenetics and corresponding studies of solid tumors gain more and more prominence. Here, first a historical perspective of molecular tumor cytogenetics is provided, which is followed by the basic principles of the fluorescence in situ hybridization (FISH) approach. Finally the current state of molecular cytogenetics in cancer diagnostics is discussed. Nowadays routine diagnostics includes basic FISH approaches rather than multicolor-FISH. The latter together with modern high-throughput methods have their impact on research to identify new tumor-associated genomic regions.

Breast cancer in China

The health burden of cancer is increasing in China, with more than 1·6 million people being diagnosed and 1·2 million people dying of the disease each year. As in most other countries, breast cancer is now the most common cancer in Chinese women; cases in China account for 12·2% of all newly diagnosed breast cancers and 9·6% of all deaths from breast cancer worldwide. China's proportional contribution to global rates is increasing rapidly because of the population's rising socioeconomic status and unique reproductive patterns. In this Review we present an overview of present control measures for breast cancer across China, and emphasise epidemiological and socioeconomic diversities and disparities in access to care for various subpopulations. We describe demographic differences between China and high-income countries, and also within geographical and socioeconomic regions of China. These disparities between China and high-income countries include younger age at onset of breast cancer; the unique one-child policy; lower rates of provision and uptake for screening for breast cancer; delays in diagnosis that result in more advanced stage of disease at presentation; inadequate resources; and a lack of awareness about breast cancer in the Chinese population. Finally, we recommend key measures that could contribute to improved health outcomes for patients with breast cancer in China.

Afatinib and its encapsulated polymeric micelles inhibits HER2-overexpressed colorectal tumor cell growth in vitro and in vivo

Colorectal cancer (CRC) is known as a common malignant neoplasm worldwide. The role of EGFR/HER2 in CRC is unclear. Afatinib is an irreversible EGFR/HER2 inhibitor. There were few studies of afatinib on CRC. Here, we investigated the protein levels/expressions of HER2 in sera and tumors from CRC patients and the therapeutic effect of afatinib on HER2-overexpressed CRC in vitro and in vivo. The increased HER2 levels were detected in the collected sera and tumors of patients with CRC. The serological HER2 levels were correlated with the tumor HER2 expressions in patients. Afatinib also inhibited the HER2-positive tumor cell growth and caused apoptosis in HER2-overexpressed human colorectal cancer HCT-15 cells but not in low HER2 expressed human gastric cancer MKN45 cells. In vivo study showed that afatinib reduced tumor growth in HER2-overexpressed xenografts. Moreover, afatinib-encapsulated micelles displayed higher cytotoxic activity in HCT-15 cells and were more effective for tumor growth suppression in HCT-15-induced tumor xenografts than afatinib performance alone. Taken together, these findings suggest that higher serum HER2 levels reflect the higher HER2 contents in tumors of CRC patients, and the improved afatinib-encapsulated micelles possess high therapeutic efficacy in HER2-overexpressed CRC in vitro and in vivo.

Changes in breast cancer reports after pathology second opinion

Breast cancer pathology reports contain valuable information about the histologic diagnosis, prognostic factors and predictive indicators of therapeutic response. A second opinion may be requested by medical oncologists and surgeons, when a patient is referred from another institution for treatment. We report the experience with pathology second opinion in selected patients referred to the Breast Oncology Unit. 205 cases referred to the Breast Oncology Unit were selected for second opinion after clinical evaluation, between 2002 and 2012. The cases reviewed included 102 core needle biopsies, 88 surgical specimens from the breast and 18 lymphadenopathies, 14 from the axillary region. Pathology second opinion was based on a review of hematoxylin-eosin preparations, recuts of submitted paraffin blocks and written external pathology reports. Immunohistochemical studies for hormone receptors, HER2, myoepithelial cells, and other markers were performed in selected cases. A case was reclassified as showing major change when second opinion showed a potential for significant change in prognosis or treatment. Otherwise, it was considered to represent minor change or to be concordant. In 52 cases (25.4%), the pathology review showed changes. Thirty-three (16%) patients were reclassified for major changes and 19 (9.2%) as minor changes. In six patients, more than one major change was identified. The major discrepancies identified were related to the histologic classification (12 cases), the presence or absence of invasion in ductal carcinoma (15 cases), the results of hormone receptors (5 cases), and HER2 (7 cases). Major changes in histologic classification included two cases diagnosed as invasive ductal carcinoma and reclassified as benign, four cases with diagnosis of breast cancer reclassified as metastatic lung cancer, one case diagnosed as small cell carcinoma of lung metastatic in the breast, reclassified as primary carcinoma of the breast, and three cases with diagnosis of breast cancer in the axilla reclassified as primary cutaneous adnexal carcinomas (2) and metastatic melanoma (1), respectively. In two cases, the histologic type of the primary breast tumor was changed. Second opinion in breast pathology may uncover significant discrepancies that impact on patient management and prognosis. Major discrepancies are most frequently related to the assessment of the presence or absence of invasion in ductal carcinoma, the results of predictive makers of therapeutic response, and the differential diagnosis of breast cancer and nonmammary tumors in the breast, the axilla, and at distant sites.

Fluorescence in situ hybridization (FISH): an increasingly demanded tool for biomarker research and personalized medicine

Extensive studies of the genetic aberrations related to human diseases conducted over the last two decades have identified recurrent genomic abnormalities as potential driving factors underlying a variety of cancers. Over the time, a series of cutting-edge high-throughput genetic tests, such as microarrays and next-generation sequencing, have been developed and incorporated into routine clinical practice. Although it is a classical low-throughput cytogenetic test, fluorescence in situ hybridization (FISH) does not show signs of fading; on the contrary, it plays an increasingly important role in detecting specific biomarkers in solid and hematologic neoplasms and has therefore become an indispensable part of the rapidly developing field of personalized medicine. In this article, we have summarized the recent advances in FISH application for both de novo discovery and routine detection of chromosomal rearrangements, amplifications, and deletions that are associated with the pathogenesis of various hematopoietic and non-hematopoietic malignancies. In addition, we have reviewed the recent developments in FISH methodology as well.