Utility and pitfalls of GATA3 immunocytochemistry for diagnosis of metastatic breast carcinoma and urothelial carcinoma on cytology specimens

Advanced hormone receptor-positive/human epidermal growth factor receptor 2-positive invasive ductal carcinoma with cecal metastasis: A case report

The incidence of gastrointestinal metastases from breast cancer (BC) is low. We report a special case of Luminal B (Hormone Receptor positive [HR+]/Human Epidermal Growth Factor receptor 2-positive [HER-2+]) BC. The patient presented with asymptomatic brain metastases two years after radical surgery for modified breast cancer and developed right lower abdominal pain during relief therapy. Electronic gastroenteroscopy revealed inflammatory changes in the cecal mucosa. These changes were confirmed on pathology to be cecal metastasis from BC. The patient's condition was stabilised after treatment with an antibody-drug conjugate (ADC). For patients with BC who develop appendicitis-like symptoms after treatment for invasive ductal carcinoma of the breast, clinicians should be fully aware that the possibility of cecal metastasis needs to be considered, despite the very low probability of occurrence.

A pilot study: Comparison of TRPS1 and GATA3 immunoperoxidase staining using cytologic smears in entities reportedly positive for GATA3

BACKGROUND

Metastatic breast carcinoma (mBC) is frequently encountered and may be challenging to diagnose as the tumor cells can morphologically resemble carcinomas of other primary origins. An additional challenge is that direct smears are often the only sample type available for immunostaining studies in cytology. Trichorhinophalangeal syndrome GATA-binding type 1 1 (TRPS1) is a highly sensitive marker for BC compared to the commonly used marker GATA3, especially in triple-negative BC (TNBC), in histologic samples. However, its sensitivity and specificity in mBC and other GATA3-positive tumors have not been studied.

METHODS

The authors identified the following cytology cases: 37 GATA3-positive mBC cases and 19 available cases that were deemed mBC but were GATA3-negative during the original case workup and five cases of each of eight epithelioid entities known to have high rates of GATA3 positivity and commonly seen in cytology practice. Immunostainings of TRPS1 and GATA3 were performed on the chosen smears following standard protocols.

RESULTS

TRPS1 was positive in all 37 GATA3-positive mBC cases and in 18 of the 19 GATA3-negative mBC cases. TRPS1 was negative in all five of the seven frequently GATA3-positive epithelioid entities, with the exception of salivary duct carcinomas where GATA3 was positive in a rate ranging 60%-100% among them.

CONCLUSIONS

TRPS1 is as sensitive as GATA3 in GATA3-positive mBC and is more sensitive than GATA3 in TNBC. TRPS1 is negative in most GATA3-positive nonbreast tumors. Thus, the combination of TRPS1 and GATA3 could be used to differentiate breast primary from others in most situations.

The diagnostic utility of trichorhinophalangeal syndrome type 1 immunohistochemistry for metastatic breast carcinoma in effusion cytology specimens

BACKGROUND

Trichorhinophalangeal syndrome type 1 (TRPS1) is a novel immunohistochemical marker with excellent performance in distinguishing breast carcinoma from other cancers in surgical specimens. The aim of this study was to evaluate the diagnostic utility of TRPS1 compared with GATA3 for metastatic breast carcinoma in effusion cytology specimens.

METHODS

In total, 91 cell blocks of malignant effusion specimens, including 47 metastatic breast carcinomas (nine triple-negative breast carcinomas [TNBCs] and 38 non-TNBCs) and 44 nonmammary malignancies, were selected for TRPS1 and GATA3 immunohistochemistry. Modified H scores ≥ 200 were considered positive staining.

RESULTS

The positive rate of TRPS1 was similar between TNBC and non-TNBC (77.8% vs 73.3%, p = .802), whereas the positive rate of GATA3 was lower in TNBC than in non-TNBC (66.7% vs 89.5%, p = .087). The positive rate of TRPS1 was significantly higher in breast carcinoma than in urothelial carcinoma (74.5% vs 0%, p < .001), whereas the positive rate of GATA3 showed no difference between these two (85.1% vs 85.7%, p = .956). Notably, diffuse and strong aberrant expression of TRPS1 was observed in one lung adenocarcinoma and one serous adenocarcinoma in this series. The overall sensitivity, specificity, positive predictive value, and negative predictive value of TRPS1 immunohistochemistry for breast carcinoma were 74.5%, 95.5%, 94.6%, and 77.8%, respectively.

CONCLUSION

TRPS1 is a sensitive and specific marker for metastatic breast cancer in serous effusion cell-block specimens. It shows superior sensitivity and specificity compared with GATA3, especially in the TNBC setting and for excluding urothelial carcinoma.

Comprehensive Review of Metastatic Breast Carcinoma in Cytology Specimens

Breast carcinomas are known to metastasize to various organs of the human body. Fine needle aspiration cytology or exfoliative cytology often are the standard method for diagnosis at these metastatic sites due to ease of procurement of diagnostic material, accessibility, less complications, high sensitivity, and specificity of diagnosis and evaluation of biomarker status needed to guide future management. This comprehensive review article discusses in detail metastatic patterns, cytomorphology of metastatic breast cancer at different body sites, immunohistochemistry needed for diagnosis of breast carcinoma, sensitivity and specificity of diagnosis and breast biomarker assays in the cytology material.

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.