Significance of GATA-3 expression in outcomes of patients with breast cancer who received systemic chemotherapy and/or hormonal therapy and clinicopathologic features of GATA-3–positive tumors

2-Hydroxypropyl-β-cyclodextrin (HPβCD) as a Potential Therapeutic Agent for Breast Cancer

Cholesterol accumulation is documented in various malignancies including breast cancer. Consequently, depleting cholesterol in cancer cells can serve as a viable treatment strategy. We identified the potency of 2-hydroxypropyl-β-cyclodextrin (HPβCD), a cholesterol-depletor in vitro against two breast cancer cell lines: MCF-7 (Oestrogen-receptor positive, ER+) and MDA-MB-231 (Triple negative breast cancer (TNBC)). The results were then compared against two non-cancerous cell lines using cytotoxic-, apoptosis-, and cholesterol-based assays. Treatment with HPβCD showed preferential and significant cytotoxic potential in cancer cells, inducing apoptosis in both cancer cell lines (p < 0.001). This was mediated due to significant depletion of cholesterol (p < 0.001). We further tested HPβCD in a MF-1 mice (n = 14) xenograft model and obtained 73.9%, 94% and 100% reduction in tumour size for late-, intermediate-, and early-stage TNBC, respectively. We also detected molecular-level perturbations in the expression patterns of several genes linked to breast cancer and cholesterol signalling pathways using RT²-PCR arrays and have identified SFRP1 as a direct binding partner to HPβCD through SPR drug interaction analysis. This work unravels mechanistic insights into HPβCD-induced cholesterol depletion, which leads to intrinsic apoptosis induction. Results from this study potentiate employing cholesterol depletion as a promising unconventional anticancer therapeutic strategy, which warrants future clinical investigations.

Value of Proline, Glutamic Acid, and Leucine-Rich Protein 1 and GATA Binding Protein 3 Expression in Breast Cancer: An Immunohistochemical study

GATA binding protein 3 was more sensitive than traditional markers such as gross cystic disease fluid protein 15 and mammaglobin for identifying primary and metastatic breast carcinomas, but its significance decreased in triple-negative breast cancer. Recent studies showed a high expression rate of proline glutamic acid and leucine-rich protein in breast cancer and their superiority over GATA3 in triple-negative breast cancer. Our study provided new insights into the diagnostic and prognostic roles of PELP1 and GATA3 in primary and metastatic breast cancer. An immunohistochemical assay was carried out using PELP1 and GATA3 in 60 cases of primary breast cancer and 15 metastatic. Invasive carcinoma of no special type was the predominant type (80%). The majority of cases were grade 3 (68.3%). GATA3 expression was 83.3% positive in primary breast carcinomas and 73.5% positive in metastatic breast carcinomas. In comparison, PELP1 had a 96.7% positive expression rate in primary breast carcinomas and an 86.7% positive expression rate in metastasis. There was a statistically significant agreement between GATA3 and PELP1 in the diagnosis of the cases. PELP1 is a significantly higher proportion of both primary and metastatic breast carcinomas than GATA3. In breast cancer, there was a strong association between favorable prognostic factors and GATA3 expression, with evidence of an inverse association with Ki-67 overexpression.

GATA3 and MDM2 are synthetic lethal in estrogen receptor-positive breast cancers

Synthetic lethal interactions, where the simultaneous but not individual inactivation of two genes is lethal to the cell, have been successfully exploited to treat cancer. GATA3 is frequently mutated in estrogen receptor (ER)-positive breast cancers and its deficiency defines a subset of patients with poor response to hormonal therapy and poor prognosis. However, GATA3 is not yet targetable. Here we show that GATA3 and MDM2 are synthetically lethal in ER-positive breast cancer. Depletion and pharmacological inhibition of MDM2 significantly impaired tumor growth in GATA3-deficient models in vitro, in vivo and in patient-derived organoids/xenograft (PDOs/PDX) harboring GATA3 somatic mutations. The synthetic lethality requires p53 and acts via the PI3K/Akt/mTOR pathway. Our results present MDM2 as a therapeutic target in the substantial cohort of ER-positive, GATA3-mutant breast cancer patients. With MDM2 inhibitors widely available, our findings can be rapidly translated into clinical trials to evaluate in-patient efficacy.

GATA3 as an Adjunct Prognostic Factor in Breast Cancer Patients with Less Aggressive Disease: A Study with a Review of the Literature

BACKGROUND

GATA binding protein 3 (GATA3) expression is positively correlated with estrogen receptor (ER) expression, but its prognostic value as an independent factor remains unclear. Thus, we undertook the current study to evaluate the expression of GATA3 and its prognostic value in a large series of breast carcinomas (BCs) with long-term follow-up.

METHODS

A total of 702 consecutive primary invasive BCs resected between 1989 and 1993 in our institution were arranged in tissue microarrays, immunostained for ER, progesterone receptor (PR), ki-67, HER2, p53, and GATA3, and scored. Clinico-pathological data were retrospectively collected.

RESULTS

GATA3 was evaluable in 608 (87%) of the 702 cases; it was positive in 413 (68%) cases and negative in 195 (32%) cases. GATA3 positivity was significantly associated with lower grade (p < 0.0001), size (p = 0.0463), stage (p = 0.0049), ER+ (p < 0.0001), PR+ (p < 0.0001), HER2- (p = 0.0175), and p53 wild-type pattern (p < 0.0001). The median follow-up was 183 months, GATA3 positivity was associated with better overall survival (HR 0.70, p = 0.001), and its prognostic value was retained in a multivariate analysis. The association with better overall survival was stronger in patients with grade 1-2, pT1-2, pN0, stage I-II, ER+, PR+, ki-67 < 20%, HER2-, a wild-type p53 immunohistochemical pattern, and in luminal B BC.

CONCLUSIONS

Our findings indicate that GATA3 is a positive prognostic marker in BC patients, especially in patients with biologically less aggressive BC. Incorporating GATA3 immunohistochemistry into routine practice could help further stratify BC patients for their risk.

The potential utility of GATA binding protein 3 for diagnosis of malignant pleural mesotheliomas

Malignant pleural mesothelioma is associated with asbestos exposure and poor outcomes. The usefulness of immunohistochemistry for diagnosis of sarcomatoid mesothelioma, especially the desmoplastic type, is limited, and more effective markers are required. GATA binding protein 3 (GATA3) has been suggested as a diagnostic marker for sarcomatoid mesothelioma. The potential usefulness of GATA3 for prognostication and its clinical and pathological correlations in different subtypes of mesothelioma have not been evaluated. We investigated the immunohistochemical labeling and associations for GATA3, BRCA1-associated protein 1 (BAP1), and Ki67 labeling in three major histological types of pleural malignant mesotheliomas. We examined 149 clinically annotated malignant mesotheliomas and assessed associations of GATA3 expression with clinical variables and prognosis. In addition, we labeled 10 cases of fibrous pleuritis with GATA3, all of which were negative. GATA3 was positive in 75 of 149 (50%) mesotheliomas, with the highest incidence of labeling seen in the sarcomatoid subtype (73%), compared with the biphasic (50%) and epithelioid (40%), mesotheliomas. A total of eight desmoplastic mesotheliomas showed labeling with GATA3. Patients whose tumors had sarcomatoid histology showed poorer survival than those with the other subtypes (p < 0.001), but overall GATA3 labeling did not have a statistically significant association with survival (p = 0.602). There was no association of GATA3 labeling and BAP1 status or Ki67 index. Our study includes the largest cohort of mesotheliomas that has been labeled for GATA3 to date. GATA3 is a useful marker for sarcomatoid mesothelioma, including the desmoplastic subtype. Discordance in GATA3 and BAP1 labeling of epithelioid and sarcomatoid components in the biphasic subtype is not uncommon.

Germline Genetic Variants in GATA3 and Breast Cancer Treatment Outcomes in SWOG S8897 Trial and the Pathways Study

INTRODUCTION

GATA3 is a critical transcription factor in maintaining the differentiated state of luminal mammary epithelial cells. We sought to determine the prognostic and predictive roles of GATA3 genotypes for breast cancer.

PATIENTS AND METHODS

Twelve single nucleotide polymorphisms (SNPs) were genotyped in 2 breast cancer cohorts, including the SWOG S8897 trial where patients were treated with adjuvant chemotherapy (CAF [cyclophosphamide, doxorubicin, 5-fluorouracil] vs. CMF [cyclophosphamide, methotrexate, 5-fluorouracil]) or untreated, and the observational Pathways Study.

RESULTS

In the S8897 trial, rs3802604 and rs568727 were associated with disease-free survival and overall survival in the treated group, regardless of chemotherapy regimen. The GG genotype of rs3802604 conferred poorer overall survival (adjusted hazard ratio, 2.45; 95% confidence interval, 1.48-4.05) and disease-free survival (adjusted hazard ratio, 1.95; 95% confidence interval, 1.27-2.99) compared with the AA genotype. Similar associations were found for rs568727. In contrast, no association with either SNP was found in the untreated group. Subgroup analyses indicated that these 2 SNPs more strongly influenced outcomes in the patients who also received tamoxifen. However, the associations in the subgroup with tamoxifen treatment were not replicated in the Pathways Study, possibly owing to substantial differences between the 2 patient cohorts, such as chemotherapy regimen and length of follow-up. Results from joint analyses across these 2 cohorts were marginally significant, driven by the results in S8897. Bioinformatic analyses support potential functional disruption of the GATA3 SNPs in breast tissue.

CONCLUSIONS

The present study provides some evidence for the predictive value of GATA3 genotypes for breast cancer adjuvant therapies. Future replication studies in appropriate patient populations are warranted.

Prognostic and clinicopathological value of GATA binding protein 3 in breast cancer: A systematic review and meta-analysis

The potential prognostic value of GATA binding protein 3 (GATA3) in breast cancer has recently increased, although the evidence is inconclusive. This meta-analysis of 10 articles involving 5,080 breast cancer patients explored the prognostic and clinicopathological value of GATA3 in breast cancer. Time to tumor progression (TTP) and overall survival (OS) were primary endpoints. Pooled hazard ratio (HR), pooled risk ratio (RR), and 95% confidence interval (CI) were calculated to evaluate the association between GATA3, prognosis, and clinicopathological parameters. High GATA3 expression predicts breast cancer, with a HR (HR = 0.671; 95% CI = 0.475–0.947; P = 0.023) of TTP, but is not associated with OS (HR = 0.889; 95% CI = 0.789–1.001; P = 0.052). GATA3 overexpression is associated with positive ER (RR = 3.155; 95% CI = 1.680–5.923; P = 0.000), positive PR (RR = 3.949; 95% CI = 1.567–9.954, P = 0.004), lower nuclear grade (RR = 0.435; 95% CI = 0.369–0.514; P = 0.000), and smaller tumor size (RR = 0.816; 95% CI = 0.709–0.940; P = 0.005). High GATA3 expression may predict TTP in breast cancer, and such patients may show better clinicopathological features.

GATA3 expression and its relationship with clinicopathological parameters in invasive breast carcinomas

GATA3, as a transcription factor, is associated with estrogen receptor (ER) expression and necessary for luminal cell differentiation in mammary glands. Association of GATA3 expression with clinicopathological parameters, molecular subtypes of tumors, disease free survival (DFS) and overall survival (OS) for breast carcinoma patients were evaluated in this study. We immunohistochemically stained GATA3, CK5/6, EGFR, CK14 and vimentin on tissue microarray blocks of 457 invasive breast carcinomas. Tumors are sub-classified as luminal A, luminal B, HER2 expressing, basal-like and null type according to their hormonal status with cerbB2, CK 5/6 and EGFR expressions. Follow-up data for 254 cases were obtained. 215/457 (47%) tumors were GATA3 positive. GATA3 expression was inversely correlated with mitotic count (p<0.0001), nuclear grade (p=0.001), histological grade (p=0.001), tumor necrosis (p=0.001), stromal lymphocytic response (p<0.01), nipple invasion (p=0.01), metastasis (p=0.03), vimentin (p=0.0003), EGFR (p=0.015) and CK14 (p=0.001) expressions; and directly associated with ER (p<0.0001) and progesterone receptor (PR) (p<0.0001) expressions. Luminal A carcinomas had the highest frequency for GATA-3 (140/245), however basal-like carcinomas had the lowest (1/42) (p<0.0001). None of the medullary and metaplastic carcinomas expressed GATA3. GATA3 was associated with good DFS and OS (p=0.001 and p=0.0009) and was an independent prognostic factor for OS. GATA3 expression, regardless of the subtype, may have a prognostic significance for breast carcinomas through its ability to promote the differentiation of luminal progenitor cells.

GATA3 expression in clinically useful groups of breast carcinoma: a comparison with GCDFP15 and mammaglobin for identifying paired primary and metastatic tumors

GATA3 has been recognized as the novel marker for identifying primary and metastatic breast carcinomas, consistently showing that GATA3 was significantly more sensitive than traditional markers gross cystic disease fluid protein 15 (GCDFP15) and mammaglobin (MGB). However, clinically useful groups of breast carcinomas status were not identified, which were determining appropriate treatment strategy, affecting the prognosis. In this study, we undertook a comparative study of the marker GATA3 and GCDFP15 and MGB in clinically useful groups of paired primary and metastatic breast cancer. We retrieved 64 cases of matched primary and metastatic breast cancer from the surgical pathology archive at our institution. According to the emerging 2015 St. Gallen Consensus, the clinically useful groups were divided into ER and/or PR (+), HER2 (-), abbreviated as A; ER and/or PR (+), HER2 (+), abbreviated as B; ER and PR (-), HER2 (+), abbreviated as C; ER, PR and HER2 (-), abbreviated as D; each group contained 16 cases (n=16). Tissue microarrays were created, with three 1-mm punch specimens from each case. The tissue microarrays were cut at 4-μm thickness and stained with monoclonal antibodies to GATA3, GCDFP15, and MGB. Staining intensity (0-3+) and extent (0%-100%) were scored with an H-score calculated (range, 0-300). Sensitivities by varying H-score cutoffs (any; ≥50; ≥150) for a positive result in the clinically useful groups of matched primary or metastatic breast cancer among GATA3, GCDFP15, and MGB. GATA3 was significantly more sensitive than GCDFP15 and MGB A and B groups (P<.05) rather than C and D groups (P>.05). However, GATA3 in conjunction with GCDFP15 and MGB detection could improve the sensitivity of C group (P<.05) rather than D group (P>.05). Significantly, good coincidence was observed between primary and metastatic tumor GATA3 expression (κ value = 0.826 >0.75) as compared with the coincidence of GCDFP15 (κ value =0.492 <0.75) and MGB (κ value =0.593 <0.75) (both P<.05). In conclusion, GATA3 expression did not show the same sensitivity for the clinically useful groups of breast cancer. GATA3 expression is positively correlated with ER-positive, PR-positive, and HER2-positive carcinomas. In addition, the matched primary and metastatic tumor expression of GATA3 shows good coincidence. We propose the careful selection of GATA3 for identifying hormone receptor negativity of breast cancer, especially in the case of triple-negative breast cancer.

Hotspot mutations delineating diverse mutational signatures and biological utilities across cancer types

Background

An important step towards personalizing cancer treatment is to integrate heterogeneous evidences to catalog mutational hotspots that are biologically and therapeutically relevant and thus represent where targeted therapy would likely be beneficial. However, existing methods do not sufficiently delineate varying functionality of individual mutations within the same genes.

Results

We observed a large discordancy of mutation rates across different mutation subtypes and tumor types, and nominated 702 hotspot mutations in 549 genes in the Catalog of Somatic Mutations in Cancer (COSMIC) by considering context specific mutation characteristics such as genes, cancer types, mutation rates, mutation subtypes and sequence contexts. We observed that hotspot mutations were highly prevalent in Non CpG-island C/G transition and transversion sequence contexts in 10 tumor types, and specific insertion hotspot mutations were enriched in breast cancer and deletion hotspot mutations in colorectal cancer. We found that the hotspot mutations nominated by our approach were significantly more conserved than non-hotspot mutations in the corresponding cancer genes. We also examined the biological significance and pharmacogenomics properties of these hotspot mutations using data in the Cancer Genome Atlas (TCGA) and the Cancer Cell-Line Encyclopedia (CCLE), and found that 53 hotspot mutations are independently associated with diverse functional evidences in 1) mRNA and protein expression, 2) pathway activity, or 3) drug sensitivity and 82 were highly enriched in specific tumor types. We highlighted the distinct functional indications of hotspot mutations under different contexts and nominated novel hotspot mutations such as MAP3K4 A1199 deletion, NR1H2 Q175 insertion, and GATA3 P409 insertion as potential biomarkers or drug targets.

Conclusion

We identified a set of hotspot mutations across 17 tumor types by considering the background mutation rate variations among genes, tumor subtypes, mutation subtypes, and sequence contexts. We illustrated the common and distinct mutational signatures of hotspot mutations among different tumor types and investigated their variable functional relevance under different contexts, which could potentially serve as a resource for explicitly selecting targets for diagnosis, drug development, and patient management.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2727-x) contains supplementary material, which is available to authorized users.

GATA3 mRNA expression, but not mutation, associates with longer progression-free survival in ER-positive breast cancer patients treated with first-line tamoxifen for recurrent disease

In breast cancer, GATA3 mutations have been associated with a favorable prognosis and the response to neoadjuvant aromatase inhibitor treatment. Therefore, we investigated whether GATA3 mutations predict the outcome of tamoxifen treatment in the advanced setting. In a retrospective study consisting of 235 hormone-naive patients with ER-positive breast cancer who received tamoxifen as first-line treatment for recurrent disease, GATA3 mutations (in 14.0% of patients) did not significantly associate with either the overall response rate (ORR) or with the length of progression-free survival (PFS) after the start of tamoxifen therapy. Interestingly, among 148 patients for whom both mutation and mRNA expression data were available, GATA3 mutations associated with an increased expression of GATA3. However, only 23.7% of GATA3 high tumors had a mutation. Evaluation of the clinical significance of GATA3 mRNA revealed that it was associated with prolonged PFS, but not with the ORR, also in multivariate analysis. Thus, GATA3 mRNA expression, but not GATA3 mutation, is an independent predictor of prolonged PFS in ER-positive breast cancer patients who received first-line tamoxifen for recurrent disease. Besides GATA3 mutation, other mechanisms must exist that underlie increased GATA3 levels.

GATA3 expression in advanced breast cancer: prognostic value and organ-specific relapse

OBJECTIVES

GATA3 is a transcription factor regulating luminal cell differentiation in the mammary glands and has been implicated in the luminal types of breast carcinoma. The prognostic significance of GATA3 in breast cancer remains controversial.

METHODS

In this study, we assessed the prognostic value of the molecule in a subset of 62 advanced breast cancers and 10 control breast cancers (no metastasis after follow-up).

RESULTS

GATA3 expression levels in luminal tumors of advanced stage were significantly higher than that of the human epidermal growth factor receptor 2 (HER2) subtype and triple-negative carcinomas, as expected, but were similar to those of the luminal controls. Furthermore, 88% of nonluminal tumors showed variable GATA3 expression, for which the HER2 subtype had significantly higher GATA3 expression than that of the triple-negative carcinomas. Interestingly, GATA3 levels were significantly lower in carcinomas with lung relapse compared to those with metastatic recurrence to other organs, thus reflecting the findings in animal models. No significant difference was observed between tumors with bone relapse and those metastasized to nonskeletal sites. Moreover, high GATA3 expression was significantly associated with favorable relapse-free survival and overall survival.

CONCLUSIONS

These findings suggest that GATA3 may not act solely as a luminal differentiation marker, and further uncovering the molecular pathways by which GATA3 regulates the downstream targets will be crucial to our understanding of breast cancer dissemination.

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.

GATA-3 expression in trophoblastic tissues: an immunohistochemical study of 445 cases, including diagnostic utility

Immunohistochemical expression of GATA-3 is seen predominantly in non-neoplastic bladder and breast epithelium and their respective carcinomas; however, data on expression in normal and lesional trophoblastic tissues are limited. Immunohistochemical staining for GATA-3 was assessed in a range of normal/lesional trophoblastic tissues and tumors in the differential diagnosis (n=445), including nonmolar products of conceptions/second and third trimester placentas/ectopic pregnancies, hydatidiform moles, placental site nodules, normal/exaggerated implantation sites, choriocarcinomas, epithelioid trophoblastic tumors, placental site trophoblastic tumors, atypical smooth muscle tumors (including leiomyosarcoma), and cervical and pulmonary squamous cell carcinomas. The extent of expression (0 to 4+) and intensity (weak to strong) were recorded. All cases with developing trophoblast/non-neoplastic trophoblastic proliferation and 81% of trophoblastic neoplasms were positive. Of all non-neoplastic trophoblast cell types, expression was observed in cytotrophoblast in 89% of cases, syncytiotrophoblast in 50%, intermediate trophoblast in 100%, and villous trophoblastic columns in 100%. Increasing gestational age was associated with a decrease in extent/intensity of expression in non-neoplastic cytotrophoblast and syncytiotrophoblast, whereas intermediate trophoblast maintained diffuse and strong expression from early to late gestation (P<0.0001). Eighty-nine percent of normal/exaggerated implantation sites showed 3+ or 4+ expression, whereas staining in 55% of placental site nodules was 1+ or 2+. Staining for GATA-3 was present in 78% of choriocarcinomas, 95% of epithelioid trophoblastic tumors, and 71% of placental site trophoblastic tumors. Although the number of choriocarcinomas and placental site trophoblastic tumors that showed a spectrum of expression ranging from negative to diffuse was relatively evenly distributed, 81% of epithelioid trophoblastic tumors had 3+ or 4+ staining. None of the atypical smooth muscle tumors and 3% of squamous cell carcinomas were positive, all of which exhibited weak staining. We conclude that GATA-3 is frequently expressed in normal and lesional trophoblastic tissues. It is also differentially expressed in intermediate trophoblast and cytotrophoblast/syncytiotrophoblast, which varies according to time during pregnancy. This study expands the spectrum of neoplasms known to express GATA-3. Thus, recognition of expression in trophoblastic tumors is important, because it can present a diagnostic pitfall in the assessment of suspected metastatic bladder or breast carcinomas involving the gynecologic tract. In the evaluation of diagnostically problematic tumors for which trophoblastic neoplasms are in the differential diagnosis, such as leiomyosarcoma and squamous cell carcinoma, GATA-3 can be included as part of an immunohistochemical panel particularly when other trophoblastic markers are either not available or yield ambiguous results.

Utility of GATA3, mammaglobin, GCDFP-15, and ER in the detection of intrathoracic metastatic breast carcinoma

INTRODUCTION

Breast carcinoma (BC) metastatic to the intrathoracic cavity is difficult to diagnose due to low sensitivity of current immunohistochemical (IHC) stains. Mammaglobin, gross cystic disease fluid protein-15 (GCDFP-15), and estrogen receptor (ER) immunomarkers show variable results. GATA3 is a recently described marker for detecting urothelial and breast cancers. Our goal is to test the utility of GATA3 in cell blocks from thoracic cytology specimens.

MATERIALS AND METHODS

We retrieved cases of BC that metastasized to the thoracic cavity from January 1, 2005 to September 30, 2013. IHC was performed on the cell blocks for the presence of GATA3, ER, GCDFP-15, and mammaglobin. Stains were scored quantitatively and qualitatively.

RESULTS

Fifty cases of metastatic BC found in pleural effusions and endobronchial ultrasound-guided fine-needle aspirates were identified in 48 patients. Thirty-four cases had sufficient material for IHC (19 pleural effusions, 15 endobronchial ultrasound-guided fine-needle aspirates). GATA3 showed strong nuclear positivity in 31 of 34 cases (91.2%). ER (25 of 34, 73.5%), mammaglobin (23 of 34, 67.6%) and GCDFP-15 (11 of 34, 32.6%) were positive in fewer cases. GATA3 and ER were concordant in 26 of 34 cases (76.5%) (24 ER/GATA3-positive, 2 ER/GATA3-negative). Discordant results were found in 8 of 34 cases (23.5%). Of these, GATA3 was positive and ER was negative in 7 cases. GATA3 was negative and ER was positive in 1 case.

CONCLUSIONS

GATA3 is more sensitive than ER, mammaglobin, or GCDFP-15 in detecting metastatic BC in cytologic specimens. GATA3 may be positive when ER is negative. In cytologic specimens with limited diagnostic material, GATA3 may be used as a first-line marker in a limited IHC panel to support metastatic BC.

The intracrinology of breast cancer

The importance of intracrinology, or in situ production of steroids from circulating precursors, in breast cancer has been firmly established in estrogen actions on postmenopausal patients. Expression levels of various steroid synthesizing and/or metabolizing enzymes have been examined in human breast cancer tissues by a number of groups. The enzymes examined include those capable of converting circulating DHEA-S to sex steroids (STS and 3βHSDΔ4-5 isomerase), the group of enzymes that modulate the strength of both androgens and estrogens (17βHSD family) as well as the androgenic 5αR enzymes and the estrogenic aromatase enzyme. In addition to these DHEA-related metabolism pathways, other intracrine pathways involving progesterone and cholesterol have also been examined. Some risk factors of breast cancer development, including obesity, have also been postulated to interact with steroid metabolising pathways. In this review, we aimed to summarise the current state of knowledge regarding intracrine metabolism including expression levels of various enzymes and receptors, focusing particularly upon the importance of the production of biologically potent steroids from circulating sulfated precursors such as DHEA-S. In addition, we attempted to summarise the factors, both steroidal and non-steroidal, involved in the regulation of these enzymes and propose future directions for research in this particular field. The concept of intracrinology was first proposed over 20 years ago but there still remain many unanswered questions which could open new horizons for the understanding of intracrine metabolism in the breast. This article is part of a Special Issue entitled 'Essential role of DHEA'.

Diagnostic utility and sensitivities of GATA3 antibodies in triple-negative breast cancer

GATA3 is implicated in mammary epithelial development and breast cancer progression and is an evolving immunohistochemical marker in breast cancer. Often associated with estrogen receptor (ER) signaling, GATA3 expression has been reported in ER-negative breast cancers, but systematic evaluation of GATA3 expression in a large set of triple-negative breast cancers (TNBC) is lacking. Given low sensitivities of mammaglobin (MGB) and GCDFP15 in metastatic TNBC, additional markers for site of origin identification would be useful in this context. We examined immunohistochemical expression of GATA3 in a large group of treatment-naive TNBC (n = 111) and ER-positive (n = 39) and HER2-positive (n = 31) breast cancers with commonly used antibody clones, HG3-31 (GATA3-H) and L50-823 (GATA3-L), and compared GATA3, MGB, and GCDFP15. Respectively, GATA3-L and GATA3-H were positive in 66% and 44% of TNBC (P = .002), 93% and 79% of ER-/HER2+ tumors (P = .596), and 100% of ER+/HER2- and ER+/HER2+ tumors (P = 1.00 each). GATA3-L was technically and diagnostically more sensitive than GATA3-H in TNBC and was technically more sensitive in other subtypes. MGB (26%) and GCDFP15 (16%) were less sensitive for TNBC than other subtypes (P < .001). Notably, 56% and 36% of MGB-/GCDFP15- TNBC were positive with GATA3-L and GATA3-H, respectively (P = .027). Seventy percent of TNBC were positive for GATA3-L, MGB, or GCDFP15 compared with 49% using GATA3-H in the panel. GATA3 is a diagnostically useful marker for TNBC and is more sensitive than MGB and GCDFP15 combined. GATA3-L is more sensitive for TNBC than GATA3-H, and an immunopanel of GATA3-L, MGB, and GCDFP15 provides optimal diagnostic sensitivity for TNBC.