Evaluation of androgen receptor and GATA binding protein 3 as immunohistochemical markers in the diagnosis of metastatic breast carcinoma to the lung

The combination of p16 and Rb expression pattern is helpful to predict high-risk HPV infection and the primary site in lymph node metastases of squamous cell carcinoma

Identifying the primary site of metastatic squamous cell carcinoma in lymph nodes can be challenging. An immunohistochemistry (IHC) analysis recently revealed that high-risk human papillomavirus (HR-HPV)-associated oropharyngeal squamous cell carcinomas (OPSCCs) typically show overexpression of p16 protein and a partial loss pattern of Rb. Nevertheless, the status of these markers in metastatic lesions is still unclear. In this study, we examined p16 and Rb expression status by IHC and transcriptionally active HR-HPV infection by mRNA in situ hybridization in paired primary and metastatic SCC lesions. A total of 50 patients with OPSCCs (n=17), hypopharyngeal SCCs (n=16), laryngeal SCCs (n=6), or uterine cervical SCCs (n=11) were enrolled. HR-HPV and p16 were positive in 21/50 (42 %) and 23/50 (46 %) patients, respectively. Primary and metastatic lesions showed concordant results for those three markers in individual patients. Among the p16-positive patients (n=23), HPV-positive cases typically showed a partial loss of Rb (n=20) and, rarely, a complete loss of Rb (n=1), whereas HPV-negative cases showed preserved Rb expression (n=2). All 27 p16-negative cases lacked HPV infection, while preserved expression and complete loss of Rb were observed in 26 and 1 of the p16-negative cases, respectively. Compared to standalone p16, the combination of p16 overexpression and Rb-partial/complete loss showed equally excellent sensitivity and negative predictive value (each 100 %) as well as improved specificity (100 % versus 93.1 %) and positive predictive value (100 % versus 91.3 %). Our results suggest that combining p16 and Rb expression patterns may be helpful in screening for HR-HPV infection in metastatic lymph nodes and in estimating the primary site of SCC.

Diagnostic utility and sensitivities of matrix Gla protein (MGP), TRPS1 and GATA3 in breast cancer: focusing on metastatic breast cancer, invasive breast carcinoma with special features, and salivary gland-type tumours

Matrix Gla protein (MGP) and trichorhinophalangeal syndrome type 1 (TRPS1) have recently emerged as novel breast-specific immunohistochemical (IHC) markers, particularly for triple-negative breast cancer (TNBC) and metaplastic carcinoma. The present study aimed to validate and compare the expression of MGP, TRPS1 and GATA binding protein 3 (GATA3) in metastatic breast carcinoma (MBC), invasive breast carcinoma (IBC) with special features, including special types of invasive breast carcinoma (IBC-STs) and invasive breast carcinoma of no special type with unique features, and mammary and non-mammary salivary gland-type tumours (SGTs). Among all enrolled cases, MGP, TRPS1 and GATA3 had comparable high positivity for ER/PR-positive (p=0.148) and HER2-positive (p=0.310) breast carcinoma (BC), while GATA3 positivity was significantly lower in TNBC (p<0.001). Similarly, the positive rates of MGP and TRPS1 in MBCs (99.4%), were higher than in GATA3 (90.9%, p<0.001). Among the IBC-STs, 98.4% of invasive lobular carcinomas (ILCs) were positive for all three markers. Among neuroendocrine tumours (NTs), all cases were positive for TRPS1 and GATA3, while MGP positivity was relatively low (81.8%, p=0.313). In the neuroendocrine carcinoma (NC) subgroup, all cases were positive for GATA3 and MGP, while one case was negative for TRPS1. All carcinomas with apocrine differentiation (APOs) were positive for GATA3 and MGP, while only 60% of the cases demonstrated moderate staining for TRPS1. Among mammary SGTs, MGP demonstrated the highest positivity (100%), followed by TRPS1 (96.0%) and GATA3 (72.0%). Positive staining for these markers was also frequently observed in non-mammary SGTs. Our findings further validate the high sensitivity of MGP and TRPS1 in MBCs, IBC-STs, and breast SGTs. However, none of these markers are capable of distinguishing between mammary and non-mammary SGTs.

Matrix Gla protein (MGP), GATA3, and TRPS1: a novel diagnostic panel to determine breast origin

Background

Metastatic breast carcinoma is commonly considered during differential diagnosis when metastatic disease is detected in females. In addition to the tumor morphology and documented clinical history, sensitive and specific immunohistochemical (IHC) markers such as GCDFP-15, mammaglobin, and GATA3 are helpful for determining breast origin. However, these markers are reported to show lower sensitivity in certain subtypes, such as triple-negative breast cancer (TNBC).

Materials and methods

Using bioinformatics analyses, we identified a potential diagnostic panel to determine breast origin: matrix Gla protein (MGP), transcriptional repressor GATA binding 1 (TRPS1), and GATA-binding protein 3 (GATA3). We compared MGP, TRPS1, and GATA3 expression in different subtypes of breast carcinoma of (n = 1201) using IHC. As a newly identified marker, MGP expression was also evaluated in solid tumors (n = 2384) and normal tissues (n = 1351) from different organs.

Results

MGP and TRPS1 had comparable positive expression in HER2-positive (91.2% vs. 92.0%, p = 0.79) and TNBC subtypes (87.3% vs. 91.2%, p = 0.18). GATA3 expression was lower than MGP (p < 0.001) or TRPS1 (p < 0.001), especially in HER2-positive (77.0%, p < 0.001) and TNBC (43.3%, p < 0.001) subtypes. TRPS1 had the highest positivity rate (97.9%) in metaplastic TNBCs, followed by MGP (88.6%), while only 47.1% of metaplastic TNBCs were positive for GATA3. When using MGP, GATA3, and TRPS1 as a novel IHC panel, 93.0% of breast carcinomas were positive for at least two markers, and only 9 cases were negative for all three markers. MGP was detected in 36 cases (3.0%) that were negative for both GATA3 and TRPS1. MGP showed mild-to-moderate positive expression in normal hepatocytes, renal tubules, as well as 31.1% (99/318) of hepatocellular carcinomas. Rare cases (0.6–5%) had focal MGP expression in renal, ovarian, lung, urothelial, and cholangiocarcinomas.

Conclusions

Our findings suggest that MGP is a newly identified sensitive IHC marker to support breast origin. MGP, TRPS1, and GATA3 could be applied as a reliable diagnostic panel to determine breast origin in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01569-1.

Secretory carcinoma of the skin with lymph node metastases and recurrence in both lungs: A case report

Secretory carcinoma of the skin is an extremely rare adnexal tumor, histopathologically identical to homologous lesions in the salivary glands and breast tissue. Although this tumor was previously reported as indolent, we report a case of secretory carcinoma of the skin with metastases and recurrence. The patient, a 31-year-old women, had a subcutaneous mass in the right axilla. The resected specimen contained a circumscribed mass, with proliferating tumor cells that exhibited prominent nucleoli. They exhibited glandular and papillary growth patterns and there were amphophilic secretions in the glands. Immunohistochemically, the tumor cells were positive for mammaglobin and S100. The tumor was surrounded by sweat glands and there was no mammary glandular tissue, suggesting that it was derived from axillary sweat glands. Accordingly, we made a diagnosis of secretory carcinoma of the skin. Four years after the operation, there were metastases in both lungs. The resected specimen revealed a tumor identical to that of the original skin tumor. Next-generation sequencing-based multiplex gene assay performed on the metastatic tissue revealed an ETV6-NTRK3 fusion gene. This is a rare case report of secretory carcinoma of the skin with lymph node metastases and recurrence in both lungs.

Difficulties in diagnostics of lung tumours in biopsies: an interpathologist concordance study evaluating the international diagnostic guidelines

AIMS

Accurate and reliable diagnosis is essential for lung cancer treatment. The study aim was to investigate interpathologist diagnostic concordance for pulmonary tumours according to WHO diagnostic criteria.

METHODS

Fifty-two unselected lung and bronchial biopsies were diagnosed by a thoracic pathologist based on a broad spectrum of immunohistochemical (IHC) stainings, molecular data and clinical/radiological information. Slides stained with H&E, thyroid transcription factor-1 (TTF-1) clone SPT24 and p40 were scanned and provided digitally to 20 pathologists unaware of reference diagnoses. The pathologists independently diagnosed the cases and stated if further diagnostic markers were deemed necessary.

RESULTS

In 31 (60%) of the cases, ≥80% of the pathologists agreed with each other and with the reference diagnosis. Lower agreement was seen in non-small cell neuroendocrine tumours and in squamous cell carcinoma with diffuse TTF-1 positivity. Agreement with the reference diagnosis ranged from 26 to 45 (50%-87%) for the individual pathologists. The pathologists requested additional IHC staining in 15-44 (29%-85%) of the 52 cases. In nearly half (17 of 36) of the malignant cases, one or more pathologist advocated for a different final diagnosis than the reference without need of additional IHC markers, potentially leading to different clinical treatment.

CONCLUSIONS

Interpathologist diagnostic agreement is moderate for small unselected bronchial and lung biopsies based on a minimal panel of markers. Neuroendocrine morphology is sometimes missed and TTF-1 clone SPT24 should be interpreted with caution. Our results suggest an intensified education need for thoracic pathologists and a more generous use of diagnostic IHC markers.

Coexpress of GATA-3 and ER in Anorectal and Head and Neck Squamous Cell Carcinoma Mimicking Metastatic Breast Cancer

GATA binding protein 3 (GATA-3) is a sensitive marker for breast and urothelial carcinomas. In combination with the estrogen receptor (ER), it is often used for differential diagnosis of metastatic carcinomas of breast origin. In this study, we sought to characterize GATA-3 and ER expression in squamous cell carcinoma (SqCC) of various origins to compare with breast carcinoma. Sixty-four SqCC of anorectum (35), head and neck (15), lung (11), and breast (3) as well as urothelial carcinoma (31) were included. In anorectal and head and neck SqCC, GATA-3, and ER was observed in 23/50 (46.0%) and 18/50 (36.0%) of the cases, respectively. The expression of GATA-3 and ER were present in both male and female patients without significant sex predominance. In 2 metastatic SqCC, the GATA-3 and ER expressed similar immunoreactivity compatible with their anorectal primary. Progesterone receptor was only expressed in 2 anorectal SqCC and none of head and neck SqCC or urothelial carcinomas. None of the lung SqCC expressed GATA-3 or ER (0/11). p16 was expressed in the majority of head and neck (6/12) and anorectal SqCC (26/27). Our study demonstrated that the combination of GATA-3 and ER positivity is not entirely specific for breast carcinomas, since both stains are expressed in SqCC from anorectal and head and neck origins. Clinical workup for metastatic carcinoma of suspicious breast origin should be cognizant of other tumors with a similar immunohistochemical profile (ie, SqCC).

Immunohistological expression of oestrogen receptor, progesterone receptor, mammaglobin, human epidermal growth factor receptor 2 and GATA-binding protein 3 in non-small-cell lung cancer

AIMS

Non-small-cell lung cancer (NSCLC) and breast cancer are common entities. Staining for oestrogen receptor (ER), progesterone receptor (PgR), mammaglobin (MAMG) and GATA-binding protein 3 (GATA3) is frequently performed to confirm a mammary origin in the appropriate diagnostic setting. However, comprehensive data on the immunohistological expression of these markers in NSCLC are limited. Therefore, the aim of this study was to analyse a large cohort of NSCLCs and correlate the staining results with clinicopathological variables.

METHODS AND RESULTS

A tissue microarray was stained for ER, PgR, MAMG, human epidermal growth factor receptor 2 (HER2), and GATA3, and included 636 adenocarcinomas (ADCs), 536 squamous cell carcinomas (SqCCs), 65 large-cell-carcinomas, 34 pleomorphic carcinomas, and 20 large-cell neuroendocrine carcinomas. HER2 status was determined for immunohistochemically positive cases with chromogenic in-situ hybridisation. Markers with a proportion of ≥5% positive cases in ADC and SqCC were considered for survival analysis. Among ADCs, 62 (10%), 17 (3%), one (<1%), seven (1%), and 49 (8%) cases were positive for ER, PgR, MAMG, HER2, and GATA3, respectively. Among SqCCs, 10 (2%), 14 (3%), two (<1%) and 109 (20%) cases were positive for ER, PgR, HER2, and GATA3, but none of the samples showed positivity for MAMG. ER positivity was associated with ADC, female sex, smaller tumour size, and lower clinical stage. None of the markers had an impact on survival.

CONCLUSION

We report on ER, PgR, MAMG, HER2 and GATA3 expression in a large cohort of NSCLCs. Interpretation of these markers in the differential diagnostic setting should be based on a multimarker panel.

SOX10 - A Novel Marker for the Differential Diagnosis of Breast Metaplastic Squamous Cell Carcinoma

Introduction

Differential diagnosis of metaplastic squamous cell carcinoma of breast (MSCCB) is difficult. In particular, in terms of metastatic MSCCB, because of the low speciality of traditional markers such as mammaglobin, gross cystic disease fluid protein-15 (GCDFP-15) and GATA binding protein 3 (GATA3), the most common problem is differentiating the spread of MSCCB to the lung from a primary lung squamous cell carcinoma. It is urgently required to explore a novel marker to aid in differential diagnosis.

Aim

The aim of this study is to explore a novel marker to aid in the differential diagnosis of MSCCB from other squamous cell carcinomas (SCC) in other organs.

Methods

We tested the expression of SOX10 in 375 human SCC specimens with immunohistochemistry (IHC).

Results

In a series of 20 MSCCB, 9 (45%) were positive for SOX10. All of them were triple-negative MSCCB. Conversely, SOX10 was totally negative in another 205 SCC originating from lung, skin, cervix, oral mucosa, and esophagus. In a series of 150 triple-negative breast cancer and their metastatic foci, SOX10 labeling in the primary tumor and metastasis was 78% and 79.3%, respectively, and the agreement rate was 97.3% (P>0.05).

Conclusion

Our findings demonstrate that SOX10 was recommended for differentiating MSCCB from non-mammary metastasis to the breast, as well as for distinguishing primary SCC from metastatic MSCCB, and SOX10 may be valuable in the pathological diagnosis of breast-derived metaplastic squamous cell carcinoma.

Differential Diagnosis of Epithelioid Malignant Mesothelioma With Lung and Breast Pleural Metastasis: A Systematic Review Compared With a Standardized Panel of Antibodies-A New Proposal That May Influence Pathologic Practice

CONTEXT.—

Pleural mesothelioma is a rare cancer with an often-challenging diagnosis because of its potential to be a great mimicker of many other tumors. Among them, primary lung and breast cancers are the 2 main causes of pleural metastasis. The development and application of targeted therapeutic agents have made it even more important to achieve an accurate diagnosis. In this setting, international guidelines have recommended the use of 2 positive and 2 negative immunohistochemical biomarkers.

OBJECTIVES.—

To define the most highly specific and sensitive minimum set of antibodies for routine practice to use for the separation of epithelioid malignant mesothelioma from lung and breast metastasis and to determine the most relevant expression cutoff.

DESIGN.—

To provide information at different levels of expression of 16 mesothelial and epithelial biomarkers, we performed a systematic review of articles published between 1979 and 2017, and we compared those data to results from the Mesothelioma Telepathology Network (MESOPATH) of the standardized panel used in routine practice database since 1998.

RESULTS.—

Our results indicate that the following panel of markers-calretinin (poly)/thyroid transcription factor 1 (TTF-1; clone 8G7G3/1) and calretinin (poly)/estrogen receptor-α (ER-α; clone EP1)-should be recommended; ultimately, based on the MESOPATH database, we highlight their relevance which are the most sensitive and specific panel useful to the differential diagnosis at 10% cutoff.

CONCLUSIONS.—

Highlighted by their relevance in the large cohort reported, we recommend 2 useful panels to the differential diagnosis at 10% cutoff.

Best Practices Recommendations for Diagnostic Immunohistochemistry in Lung Cancer

Since the 2015 WHO classification was introduced into clinical practice, immunohistochemistry (IHC) has figured prominently in lung cancer diagnosis. In addition to distinction of small cell versus non-small cell carcinoma, patients' treatment of choice is directly linked to histologic subtypes of non-small cell carcinoma, which pertains to IHC results, particularly for poorly differentiated tumors. The use of IHC has improved diagnostic accuracy in the classification of lung carcinoma, but the interpretation of IHC results remains challenging in some instances. Also, pathologists must be aware of many interpretation pitfalls, and the use of IHC should be efficient to spare the tissue for molecular testing. The International Association for the Study of Lung Cancer Pathology Committee received questions on practical application and interpretation of IHC in lung cancer diagnosis. After discussions in several International Association for the Study of Lung Cancer Pathology Committee meetings, the issues and caveats were summarized in terms of 11 key questions covering common and important diagnostic situations in a daily clinical practice with some relevant challenging queries. The questions cover topics such as the best IHC markers for distinguishing NSCLC subtypes, differences in thyroid transcription factor 1 clones, and the utility of IHC in diagnosing uncommon subtypes of lung cancer and distinguishing primary from metastatic tumors. This article provides answers and explanations for the key questions about the use of IHC in diagnosis of lung carcinoma, representing viewpoints of experts in thoracic pathology that should assist the community in the appropriate use of IHC in diagnostic pathology.

The prognostic value of androgen receptors in breast cancer subtypes

PURPOSE

Androgen receptor (AR) expression is frequent in breast cancer and has been associated with good prognosis in several studies. The present study investigates AR-expression in relation to molecular subtypes, clinicopathological features and prognosis in 1297 primary tumours and 336 paired axillary lymph node metastases (LNM) from two cohorts of Norwegian patients.

METHODS

Immunohistochemistry for AR was performed on tumours previously reclassified into molecular subtypes using immunohistochemistry and in situ hybridisation. Associations between AR-expression and clinical features were studied using Chi-square tests. Cumulative incidence of breast cancer death and Cox regression analyses were used to assess prognosis.

RESULTS

AR-positivity was found in 78.0% of all cases, 84.9% of luminal and 45.1% of non-luminal tumours. The highest proportion of AR-positivity was found in Luminal B tumours, and the lowest in the Basal phenotype. Discordance in AR-status between primary tumours and lymph node metastases was observed in 21.4% of cases. A switch from AR^- primary tumour to AR⁺ lymph node metastasis was seen in 60/72 discrepant cases. AR-expression in primary tumours was an independent and favourable prognostic marker (HR 0.70, 95% CI 0.55-0.90), particularly in the Luminal A subtype, and in grade 3 tumours.

CONCLUSIONS

AR is an independent predictor of good prognosis in BC, particularly in grade 3 and Luminal A tumours. Discordant AR-expression between primary tumour and LNM was observed in 21.4% of cases and most often there was a switch from AR^- primary tumour to AR⁺ axillary LNM.

HER2/HER3-positive metastatic salivary duct carcinoma in the pleural effusion: A case report

Salivary duct carcinoma (SDC) is an aggressive form of salivary gland tumor, and SDC patients tend to be older men, more commonly in advanced stage with a poorer prognosis. Although the cytological characteristics of SDC on fine-needle aspiration cytology have been well-described at the primary site, they have not been explored in metastasis. Here we reported a case of HER2/HER3-positive metastatic SDC in the lung and pleural effusion. The patient was a man in his 50s who had undergone extended total parotidectomy in 2008. He was originally diagnosed as having HER2-positive left parotid SDC. Six years later a mass was discovered in the left lung by chest computed tomography (CT) and was diagnosed as metastatic SDC by both bronchial biopsy and cytology. Subsequently he had a recurrent SDC in the left pleural effusion and died of respiratory failure. Cytological findings from bronchial brushing smear showed small sheet clusters in a slightly necrotic background. In the pleural effusion cytology, tumor cells appeared as ball-like clusters of epithelioid cells with apocrine-like findings. In immunocytochemistry, HER3 of SDC cells in pleural effusion was significantly overexpressed relative to the matched primary tumor, even though HER2 amplification did not change. Cytological findings and HER family receptors differed between the primary and metastatic SDC. Therefore, molecular tests, such as protein expression and gene amplification using cytological specimens, may become important in future when determining therapy strategies in patients with distant metastasis.

Prognostic impact of GATA binding protein-3 expression in primary lung adenocarcinoma

GATA binding protein-3 (GATA3) is a transcription factor that regulates cell differentiation and maintenance in some types of normal cells. This study aimed to investigate the association between GATA3 expression and primary lung adenocarcinoma and to clarify the clinical significance of GATA3 expression in lung adenocarcinoma. Immunohistochemical GATA3 expression was evaluated using completely resected lung adenocarcinoma samples from 95 cases. GATA3 immunohistochemical staining was performed and scored. Associations between clinicopathological factors and GATA3 expression were analyzed by using the χ² test and Fisher exact test. The Kaplan-Meier method was used to analyze overall survival (OS) and disease-free survival (DFS). Forty-nine cases expressed high levels of GATA3, which were associated with lymphatic invasion (P=.003). In univariate and multivariate analyses, vascular invasion (P<.001) and high GATA3 expression (P=.023) were identified as independent risk factors for OS. Higher pathological stages (P=.012), vascular invasion (P=.010), and high GATA3 expression (P=.009) were identified as independent risk factors for DFS. The high GATA3 expression group exhibited statistically worse OS (P=.031) and DFS (P=.011) than the low-expression group based on the Kaplan-Meier curves. In resected lung adenocarcinoma, high GATA3 expression is associated with poorer prognosis for both OS and DFS. Therefore, the immunohistochemical evaluation of GATA3 represents a potentially useful prognostic tool for postoperative patients.

MMTV-PyMT and Derived Met-1 Mouse Mammary Tumor Cells as Models for Studying the Role of the Androgen Receptor in Triple-Negative Breast Cancer Progression

Triple-negative breast cancer (TNBC) has a faster rate of metastasis compared to other breast cancer subtypes, and no effective targeted therapies are currently FDA-approved. Recent data indicate that the androgen receptor (AR) promotes tumor survival and may serve as a potential therapeutic target in TNBC. Studies of AR in disease progression and the systemic effects of anti-androgens have been hindered by the lack of an AR-positive (AR+) immunocompetent preclinical model. In this study, we identified the transgenic MMTV-PyMT (mouse mammary tumor virus-polyoma middle tumor-antigen) mouse mammary gland carcinoma model of breast cancer and Met-1 cells derived from this model as tools to study the role of AR in breast cancer progression. AR protein expression was examined in late-stage primary tumors and lung metastases from MMTV-PyMT mice as well as in Met-1 cells by immunohistochemistry (IHC). Sensitivity of Met-1 cells to the AR agonist dihydrotestosterone (DHT) and anti-androgen therapy was examined using cell viability, migration/invasion, and anchorage-independent growth assays. Late-stage primary tumors and lung metastases from MMTV-PyMT mice and Met-1 cells expressed abundant nuclear AR protein, while negative for estrogen and progesterone receptors. Met-1 sensitivity to DHT and AR antagonists demonstrated a reliance on AR for survival, and AR antagonists inhibited invasion and anchorage-independent growth. These data suggest that the MMTV-PyMT model and Met-1 cells may serve as valuable tools for mechanistic studies of the role of AR in disease progression and how anti-androgens affect the tumor microenvironment.

Markers of metastatic carcinoma of breast origin

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging. GATA3 is a nuclear transcription factor that shows superior sensitivity to GCDFP-15 and mammaglobin. However, the specificity of GATA3 can pose challenges, inasmuch as carcinomas of the bladder and other sites can show significant levels of positivity. Determination of the optimal panel of antibodies employed in a given clinical setting will thus depend on the non-breast tumours included in the differential diagnosis.

Expression patterns of GATA3 and the androgen receptor are strongly correlated in patients with triple-negative breast cancer

GATA-binding protein 3 (GATA3) is a diagnostically useful immunohistochemical marker of breast cancer. Because of its strong association with estrogen receptor expression, GATA3 has markedly reduced sensitivity in triple-negative breast cancer (TNBC). We constructed a tissue microarray using a large series of TNBCs and evaluated GATA3 expression by TNBC subtype as defined by surrogate immunohistochemical markers. A total of 205 TNBCs were classified into cancers of the molecular apocrine type (n=23, 11.2%), claudin-low type (n=21, 10.2%), basal-like type (n=91, 44.4%), mixed type (n=62, 30.2%), and null type (n=8, 3.9%). The GATA3 scores (staining intensity × proportion) were categorized as negative (0), focally positive (1-10), or positive (11-300). GATA3 staining was negative in 153 cancers (74.6%), focally positive in 11 (5.4%), and positive in 41 (20.0%). The rate of focal positivity or positivity for GATA3 was significantly higher in the molecular apocrine type (73.9%, 17/23) than in other types of TNBCs (P=.001). The mean GATA3 score of molecular apocrine-type TNBC was significantly higher than that of the other types (P=.001) and differed significantly between androgen receptor (AR)-positive and AR-negative TNBCs (P<.001). In conclusion, GATA3 expression was correlated strongly with AR-positive, molecular apocrine-type TNBCs. Co-expression of AR and GATA3 is a specific feature of molecular apocrine-type TNBC, which may serve as a diagnostic aid for cancer of unknown primary.

The role of GATA3 in breast carcinomas: a review

GATA3 is a zinc-binding transcription factor that regulates the differentiation of many human tissue types, including the mammary gland. In surgical pathology, immunohistochemistry for GATA3 is largely used to support urothelial or breast origin in a carcinoma of unknown origin. GATA3 is sensitive but not entirely specific in this setting. Although GATA3 labeling is highest in estrogen receptor-positive carcinomas, it also labels estrogen receptor-negative carcinomas and thus has particular diagnostic utility in the setting of triple-negative breast carcinomas, which are typically negative for other mammary-specific markers.

Differential expression of immunohistochemical markers in primary lung and breast cancers enriched for triple-negative tumours

AIMS

In breast cancer patients presenting with a lung lesion, the distinction between lung and breast origin is clinically important. Lung and breast cancers are both CK7(+) /CK20(-) , so additional immunohistochemical markers are needed.

METHODS AND RESULTS

We examined the expression of oestrogen receptor (ER), progesterone receptor (PR), thyroid transcription factor-1 (TTF-1), gross cystic disease fluid protein-15 (GCDFP-15), p63 and Wilms' tumour 1 (WT1) in a series of tissue microarrays comprising 266 non-small-cell lung cancers and 837 primary breast cancers enriched for triple-negative tumours (TNBC). Staining for ER, PR, TTF-1 and GCDFP-15 was present in 63%, 49%, 0% and 25% of breast and 6%, 9%, 59% and 1% of lung cancers, respectively. Strong staining for p63 was present in 63 (97%) lung squamous cell carcinomas and only eight (9%) TNBC. WT1 nuclear staining was rare; however, cytoplasmic staining was identified in 49 (40%) TNBC and 10 (5%) lung cancers. Cluster analysis segregated TNBC from lung cancers with TTF-1 and/or p63 staining favouring lung origin, and GCDFP-15 or WT1 staining favouring breast origin. Cancers negative for all four markers (17%) were 60% breast and 40% lung origin.

CONCLUSION

An immunohistochemical panel incorporating ER, TTF-1, GCDFP-15, p63 and WT1 can help to distinguish lung cancer from metastatic breast cancer, including TNBC.