Estrogen and progesterone hormone receptor status in breast carcinoma: Comparison of immunocytochemistry and immunohistochemistry

Best practices for achieving consensus in HER2-low expression in breast cancer: current perspectives from practising pathologists

AIMS

Human epidermal growth factor receptor 2 (HER2) expression is an important biomarker in breast cancer (BC). Most BC cases categorised as HER2-negative (HER2-) express low levels of HER2 [immunohistochemistry (IHC) 1+ or IHC 2+/in-situ hybridisation not amplified (ISH-)] and represent a clinically relevant therapeutic category that is amenable to targeted therapy using a recently approved HER2-directed antibody-drug conjugate. A group of practising pathologists, with expertise in breast pathology and BC biomarker testing, outline best practices and guidance for achieving consensus in HER2 IHC scoring for BC.

METHODS AND RESULTS

The authors describe current knowledge and challenges of IHC testing and scoring of HER2-low expressing BC and provide best practices and guidance for accurate identification of BCs expressing low levels of HER2. These expert pathologists propose an algorithm for assessing HER2 expression with validated IHC assays and incorporate the 2023 American Society of Clinical Oncology and College of American Pathologist guideline update. The authors also provide guidance on when to seek consensus for HER2 IHC scoring, how to incorporate HER2-low into IHC reporting and present examples of HER2 IHC staining, including challenging cases.

CONCLUSIONS

Awareness of BC cases that are negative for HER protein overexpression/gene amplification and the related clinical relevance for targeted therapy highlight the importance of accurate HER2 IHC scoring for optimal treatment selection.

Immunohistochemistry Applied to Breast Cytological Material

Fine-needle aspiration biopsies (FNABs) of the breast are minimally invasive procedures enabling the diagnosis of suspicious breast lesions. Unfortunately, they are often perceived as inferior to core-needle biopsies, namely because they are supposedly unable to differentiate between high-grade ductal carcinoma in situ and invasive carcinoma or provide material for ancillary testing. Several studies have shown, however, that FNAB samples, when handled properly, are indeed capable of providing sufficient and adequate material for ancillary testing, namely immunocytochemistry (ICC). We reviewed the published literature regarding the use of ICC for both diagnostic and theranostic uses in the different types of cytological samples obtained from FNABs of the breast, including smears, liquid-based cytology samples, and cellblocks. We found that p63 and 34βE12 show promise in aiding in the differential diagnosis between in situ and invasive lesions and that most other diagnostic markers may be used as in tissue. Regarding theranostic ICC markers, results vary between publications, but with care, these can successfully be performed in cytological samples. Air-dried smears should be avoided, and cellblocks are overall more versatile than cytology slides, enabling the evaluation of not only hormonal receptors and HER2 by ICC, but also of Ki-67. Particular attention should be paid to fixation and antigen retrieval procedures in all cases. We recommend that laboratories without experience perform short validation runs before adopting these techniques into clinical practice.

Knockdown of EIF3C promotes human U-2OS cells apoptosis through increased CASP3/7 and Chk1/2 by upregulating SAPK/JNK

Background

As a component of the EIF3 complex, EIF3C is essential for several steps in protein synthesis initiation. Recently, it has been addressed that EIF3C is overexpressed in several human cancers and plays a pivotal role in cell proliferation and tumorigenesis.

Materials and methods

Immunohistochemistry, quantitative real-time PCR (qPCR), and Western blotting assays were employed to determine the expression of EIF3C in osteosarcoma (OsC) tissues obtained from 60 patients. The levels of EIF3C mRNA and protein were assessed by qPCR and Western blotting, respectively. The effect of EIF3C knockdown on OsC cell proliferation was detected by MTT and colony formation assays, respectively. Cell apoptosis induced by EIF3C silencing was analyzed by flow cytometric analysis. PathScan stress and apoptosis signaling antibody array kit was used to analyze the potential effects of EIF3C knockdown on OsC cells.

Results

The levels of EIF3C were high in OsC tissues and cell lines. In addition, EIF3C knockdown by lentivirus-mediated shRNA targeting EIF3C significantly suppressed cell proliferation and colony formation and induced apoptosis in U-2OS cells. Moreover, EIF3C knockdown led to the upregulated expression of CASP3/7, Chk1/2, and SAPK/JNK, indicating that the downregulated expression of EIF3C might be associated with pro-apoptosis of U-2OS cells.

Conclusion

EIF3C may be a promising target for gene therapy of human OsC. However, the precise mechanisms behind the effect of EIF3C on OsC tumorigenesis require further analysis.

Evaluation of Estrogen and Progesterone Receptors and Her-2 Expression with Grading in the Fine-needle Aspirates of Patients with Breast Carcinoma

Background:

There has been a limited literature with regards to comparison between the pre-operative hormonal/Her-2 neu assessment by immunostaining on fine-needle aspiration (FNA) versus core needle biopsies (CNBs) and their correlation with grading of breast carcinoma.

Materials and Methods:

Two hundred fifty FNAs and 201 CNBs from 252 patients with breast carcinoma were subjected immunocytochemical/histochemical (ICC/IHC) staining along with the grading by the Robinson cytologic and modified Scarff-Bloom-Richardson scoring systems, respectively. Depending on the material adequacy, IHC was also performed on cell blocks. Sensitivity, specificity, and predictive values of ICC were calculated. The kappa statistics was performed to see the power of the study. Cytologic versus histologic gradings were compared and analysed by percentage analysis.

Results:

Sensitivity of ICC on FNAs for ER, PR, and Her-2neu was 49%, 28.8%, and 46%, respectively, while specificity was 84.5%, 90.6%, and 86.6%, respectively, with a fair agreement on kappa statistics. Her-2neu positivity on CNB versus FNA had a moderate agreement. Her-2neu staining of 3+ was seen in most of the Grade-2 tumours on FNA.

Conclusions:

Fairly reliable results on grading and hormonal/Her-2neu status are possible when ICC is performed on qualitatively superior FNA material. This is particularly useful in the management of patients in certain settings like inoperable cases.

Centromere protein U is a potential target for gene therapy of human bladder cancer

To investigate the role of centromere protein U (CENPU) in human bladder cancer (BCa), CENPU gene expression was evaluated in human BCa tissues. We used real-time quantitative PCR (qPCR) and found that CENPU gene expression in human BCa tissues was higher compared to that observed in cancer-adjacent normal tissues. High CENPU expression was found to be strongly correlated with tumor size and TNM stage. Kaplan-Meier survival analysis indicated that high CENPU levels were associated with reduced survival. We used a lentivirus to silence endogenous CENPU gene expression in the BCa T24 cell line. CENPU knockdown was confirmed by qPCR. Cellomic imaging and BrdU assays showed that cell proliferation was significantly reduced in the CENPU-silenced cells compared to that noted in the control cells. Flow cytometry revealed that in the CENPU-silenced cells the cell cycle was arrested at the G1 phase relative to that in the control cells. In addition, apoptosis was significantly increased in the CENPU-silenced cells. Giemsa staining showed that CENPU-silenced cells, compared to control cells, displayed a significantly lower number of cell colonies. The genome-wide effect of CENPU knockdown showed that a total of 1,274 differentially expressed genes was found, including 809 downregulated genes and 465 upregulated genes. Network analysis by Ingenuity Pathway Analysis (IPA) resulted in 25 distinct signaling pathways, including the top-ranked network: ‘Cellular compromise, organismal injury and abnormalities, skeletal and muscular disorders’. In-depth IPA analysis revealed that CENPU was associated with the HMGB1 signaling pathway. qPCR and western blot analysis demonstrated that in the HMGB1 signaling pathway, CENPU knockdown downregulated expression levels of ILB, CXCL8, RAC1 and IL1A. In conclusion, our data may provide a potential pathway signature for therapeutic targets with which to treat BCa.

Comparison of Immunocytochemistry and Immunohistochemistry on Breast Carcinoma: A Boon or a Bane?

Introduction:

Breast carcinoma is the most common cancer among women in the urban Indian population. Conventionally, immunohistochemistry (IHC) is done to determine the hormone receptor status of the tumor. Immunocytochemistry (ICC) on fine-needle aspiration cytology (FNAC) was carried out to determine the same hormone receptor status of the tumor.

Objective:

The study was undertaken to evaluate the diagnostic reliability of performing estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her2/neu) receptor status on FNAC by ICC and to compare the results with IHC.

Materials and Methods:

A 2 years 6 months prospective study conducted in the Department of Pathology, ESIC Medical College and PGIMSR and ESIC Model Hospital, Rajajinagar, Bengaluru, wherein 100 breast carcinoma patients' samples both cytology and histology were collected. IHC and ICC were done by peroxidase antiperoxidase technique. Validations of the receptor status were analyzed using sensitivity, specificity, positive and negative predictive values (PPV and NPV), and kappa statistics for agreements between ICC and IHC.

Results:

ICC was positive for ER, PR, and Her2/neu in 53, 50, and 22 cases, respectively. For ER, a cytohistologic correlation of 98%, with a sensitivity of 96.3%, specificity of 100%, and PPV and NPV being 100% and 95.7%. For PR, concordance of 97%, with a sensitivity of 94.3%, specificity of 100%, and PPV and NPV being 100% and 94%. Her2/neu had an agreement of 89%, with a sensitivity of 72%, specificity of 95.5%, and PPV and NPV being 85.7% and 90.1%.

Conclusion:

ICC has been a boon and can be a paramount diagnostic adjunct to the routine investigations.

Utility of immunochemistry in cytology

Background:

The role played by cytology in primary diagnosis is undeniable. With improved management protocols and targeted therapy, the need for accurate diagnosis has become mandatory. Immunochemistry and molecular techniques are increasingly being used on limited tissue samples.

Aims:

This study was conducted to find out the impact of immunocytochemistry (ICC) on cytology material in cytology practice.

Materials and Methods:

Immunochemistry was done on alcohol-fixed smears and cell-block preparations. It was done with i6000 BioGenex autostainer using BioGenex reagents.

Results:

A total of 148 cases occurring over a period of 3 years (September 2010-June 2013) were analyzed. Staining was done on cytology smears in 77 cases and on cell-block sections in 71 cases. ICC helped in diagnosis in 8 cases, confirmed the diagnosis in 26 cases, helped in subtyping in 60 cases, and helped in prognostication in 6 cases. ICC has altered the diagnosis in two cases. It was noncontributory in 43 cases, and the material was inadequate in three cases.

Conclusion:

In 102 cases (69%), ICC proved to be a useful adjunct in the diagnosis and prognostication; hence, its use is recommended in practice to aid in cytology services.

Evaluation of grading and hormone receptor immunostaining on fine needle aspirates in carcinoma breast

Background:

Grading and hormone receptor determination in breast carcinoma are predictive factors for response to hormonal therapy.

Aim:

This study was undertaken to grade breast carcinoma and to determine estrogen receptor (ER) and progesterone receptor (PR) expression on fine-needle aspiration cytology (FNAC). Furthermore, the objective was to compare the results with histological grading and immunohistochemistry on surgical material.

Materials and Methods:

Fifty cases of breast carcinoma diagnosed on FNAC were included. The cytological grading was done according to the Robinson's grading system. The corresponding histology sections were graded using the modified Bloom-Richardson system. Immunostaining for ER and PR was done on smears and tissue sections.

Results:

On both cytological and histological evaluation, 49 cases were infiltrating ductal carcinoma and one case was colloid carcinoma. On comparing cytological and histological grading, 78% were correctly graded on cytology. The sensitivity, specificity, positive predictive value and negative predictive value for ER detection on immunocytochemistry (ICC) were 55.6%, 95%, 93.8% and 61.3%, respectively. The sensitivity, specificity, positive and negative predictive value for PR detection on ICC were 57.7%, 95.2%, 93.8% and 64.5%, respectively. The correlation for ER and PR between cytology and histology was 72.3% and 74.5%.

Conclusion:

The grading along with ER and PR immunostaining of breast carcinoma on smears is advocated because of high concordance between cytology and histology. This allows the patient to be treated with hormonal therapy on the basis of FNAC alone.

Detection of circulating tumor cell-specific markers in breast cancer patients using the quantitative RT-PCR assay

BACKGROUND

Breast cancer is a highly prevalent disease among women worldwide. While the expression of certain proteins within breast cancer tumors is used to determine the prognosis and select therapies, additional markers need to be identified. Circulating tumor cells (CTCs) are constituent cells that have detached from a primary tumor to circulate in the bloodstream. CTCs are considered the main source of breast cancer metastases; therefore, detection of CTCs could be a promising diagnostic method for metastatic breast cancer.

METHODS

In this study, the CircleGen CTC RT-qDx assay was used to analyze the mRNA expression levels of six CTC-specific markers including EpCAM, CK19, HER2, Ki67, hTERT, and vimentin with a total of 692 peripheral whole blood samples from 221 breast cancer patients and 376 healthy individuals.

RESULTS

This assay showed high specificity with multiple markers; none of the healthy controls were detected positive, whereas 21.7 and 14 % of breast cancer patients were positive for EpCAM and CK19, respectively. Of the 221 breast cancer patients, 84 (38 %), 46 (20.8 %), 83 (37.6 %), and 39 (17.6 %) were positively for HER2, Ki67, hTERT, and vimentin mRNA, respectively. Of the 84 patients who were HER2 positive, nine (4 %) were also positive for EpCAM, CK19, Ki67, hTERT, and vimentin. Of the 139 breast cancer patients who were HER2 negative, 65 (29.1 %) were negative for EpCAM, CK19, Ki67, hTERT, and vimentin. Furthermore, the EpCAM-positive population decreased from 21.5 to 8.3 % after completion of anti-tumor treatment (TP4). Similarly, the CK19, HER2, hTERT, and vimentin positives also decreased from 13.9 to 9.5 %, from 37.7 to 21.4 %, from 37.2 to 33.3 %, and from 17.5 to 14.3 %, respectively, after completion of anti-tumor treatment. In contrast, the Ki67 positives increased from 20.6 to 41.7 % after completion of anti-tumor treatment.

CONCLUSIONS

mRNA overexpression of six CTC-specific markers was detected by the CircleGen CTC RT-qDx assay with high specificity, and the obtained mRNA expression levels of CTC-specific markers might provide useful criteria to select appropriate anti-tumor treatment for breast cancer patients.

Detection of circulating tumor cells in patients with breast cancer using the quantitative RT-PCR assay for monitoring of therapy efficacy

Circulating tumor cells (CTCs) are an independent prognostic factor for patients with breast cancer. However, the role of CTCs in early breast cancer management is not yet clearly defined. The aim of this study was to isolate and characterize CTCs in blood sample of a breast cancer patient as a biomarker for monitoring treatments efficacy. In this study, 692 blood samples from 221 breast cancer patients and 376 healthy individuals was used to detect CTCs with multiple markers including epithelial cell adhesion molecule (EpCAM), cytokeratin (CK) 19, human epidermal growth factor (HER) 2, Ki67, human telomerase reverse transcriptase (hTERT), and vimentin using quantitative reverse transcription PCR (RT-qPCR). A total of 153 (69.2%) blood samples of 221 patients with breast cancer were found to be positive for at least one of the cancer-associated marker gene before treatment. After chemotherapy, no CTCs were found in 28 (33.3%) of the 84 blood samples analyzed for the presence of CTCs using the RT-qPCR, whereas 56 (66.7%) blood samples were still found to be positive for at least one of the markers. After completing the therapy, the CTC positivity rate decreased to 7 (20.6%) in the neoadjuvant group, whereas this increased to 7 (14%) cases in the adjuvant group. There was no statistically significant relationship between TNM stage and detection of CTC-related markers. Data from this study suggest that RT-qPCR assay for the detection of CTC markers might be useful in selecting appropriate therapeutics and for monitoring treatment efficacy in breast cancer patients.

Low concordance of biomarkers in histopathological and cytological material from breast cancer

AIMS

The aim of this study was to investigate in primary breast cancer the congruency of routine clinical predictive biomarker evaluations, including ER, PR and Ki67, obtained using immunocytochemistry (ICC) and immunohistochemistry (IHC).

METHODS AND RESULTS

Clinicopathological data were collected on all women diagnosed with primary breast cancer at Karolinska University Hospital in 2011. A total of 346 patients were included in a retrospective paired comparison of predictive biomarker evaluations on direct smear ICC and IHC. This showed a low congruency between findings with the two methods, especially evident for Ki67 (κ = 0.35-0.42). By suggested adjustments to ICC cut-offs, we managed to improve the inter-rater agreement of Ki67 classification slightly to κ = 0.46.

CONCLUSIONS

Our findings suggest that routine clinical ICC and IHC evaluations of predictive biomarkers produce discordant results. Consequently, basing therapeutic decisions on cytology with cut-offs defined for IHC induces a risk that patients will receive suboptimal therapy. However, our analysis shows that local adjustments to biomarker cut-off levels may improve congruency and increase the probability of correct classifications.