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

TRPS1 function beyond breast: A retrospective immunohistochemical study on non-breast cytology specimens

INTRODUCTION

Trichorhinophalangeal syndrome type 1 (TRPS1) has emerged as a reliable immunohistochemistry (IHC) marker for identifying breast origin in metastatic carcinomas. This study investigates the utility of TRPS1 IHC in non-breast cytology specimens.

MATERIALS AND METHODS

A retrospective search of our pathology database for the year 2021 identified fluids (pleural and peritoneal) and liver, lung and bone fine needle aspirations (FNAs) with surgical follow-up confirming non-breast metastatic carcinomas. Cell blocks from cases with sufficient neoplastic cells underwent immunostaining using a rabbit polyclonal antibody against human TRPS1. Cases lacking tumor on deeper levels after the original work-up were excluded from the study. Two pathologists independently interpreted the TRPS1 staining.

RESULTS

Of 136 cases assessed, 31 (22.79%) exhibited positive TRPS1 staining, while 105 (77.21%) were nonreactive. Positivity rates were observed in tumors of Mullerian cell origin, gastrointestinal tract (GIT), and lung origin at 28.85%, 25%, and 21.57%, respectively. Of the tumors of Mullerian cell origin 10 (66.67%) were serous carcinomas, 4 (26.67%) were endometrioid carcinomas, and one (6.67%) was a clear cell carcinoma. Lung tumors comprised seven (63.64%) squamous cell carcinomas and four (36.36%) adenocarcinomas, while the gastrointestinal tumors consisted of 14 (80%) adenocarcinomas and one (20%) squamous cell carcinoma.

CONCLUSIONS

Although recognized as a sensitive marker for mammary carcinomas, TRPS1 immunostaining was also detected in Mullerian, lung, and GIT carcinomas. This highlights the significance of being cautious when depending solely on TRPS1 immunostaining to distinguish metastatic breast tumors.

TRPS1 expression in primary and metastatic prostatic adenocarcinoma, muscle invasive bladder urothelial carcinoma, and breast carcinoma: Is TRPS1 truly specific and sensitive for a breast primary?

Trichorhinophalangeal syndrome type 1 (TRPS1) has been reported to be a sensitive and specific immunohistochemical (IHC) marker for breast carcinomas, especially when determining primary site of origin. However, there is limited data on TRPS1 expression in prostate and bladder cancers. A two-phase study was performed with 1) an exploratory cohort analyzing TRPS1 gene alterations in prostate, bladder, and breast carcinoma and TPRS1 mRNA expression data in prostate and bladder carcinoma; and 2) TRPS1 and GATA3 IHC in a confirmatory cohort in prostate, bladder, and breast carcinoma samples. Gene alterations were identified in a subset of breast, bladder, and prostate carcinomas and mRNA was consistently detected. In the IHC cohort, 183/210 (87.1 %) of breast, 22/69 (31.9 %) of prostate, and 20/73 (27.4 %) of urothelial carcinomas showed staining with TRPS1. Intermediate to high expression of TRPS1 was observed in 173/210 (82.8 %) of breast, 17/69 (24.6 %) of prostate, and 15/73 (20.5 %) of urothelial carcinomas. Furthermore, in prostate cancer, 26.9 % of pelvic lymph node metastases and 50 % in sites of distant metastases showed expression. Increased TRPS1 mRNA expression (p = 0.032) and IHC expression (p = 0.040) correlated with worse overall survival in bladder cancer. By comparison, GATA3 IHC stained 136/210 (64.8 %) of breast, 0/69 (0 %) of prostate, and 63/73 (93 %) of bladder carcinomas. Intermediate to high expression of GATA3 was seen in 131/210 (62.4 %) of breast and 63/73 (93 %) of bladder carcinomas. This study shows there is significant staining of TRPS1 in bladder and prostate cancers. As a result, comprehensive studies are needed to establish the true specificity of TRPS1 IHC stain across various tumor types before its widespread clinical adoption.

Comparative expression of TRPS1, GATA3, SOX10, mammaglobin, and GCDFP-15 in effusion specimens with breast carcinoma

BACKGROUND

Traditional immunohistochemistry (IHC) for breast carcinomas has shown low detection rates of metastatic breast carcinoma (MBC) in effusions. Although GATA3 has enhanced diagnostic accuracy in this realm, its limited utility in detecting triple-negative breast carcinoma (TNBC) has been highlighted. TRPS1 has been introduced as a potentially sensitive and specific marker in detecting MBC on histologic samples. We investigate the utility of TRPS1 as a marker for MBC in effusion specimens and compare its performance to SOX10, GATA3, mammaglobin (MG), and GCDFP-15.

METHODS

A database search identified malignant effusions involved by MBC between 2013 and 2021. Cases from unique patients with sufficient cellularity were evaluated for TRPS1, GATA3, SOX10, MG, and GCDFP-15 IHC. The intensity and extent of tumor cells (TC) were scored by two pathologists. Any discrepancies were jointly reviewed for consensus.

RESULTS

GATA3 showed the highest rate of positivity (98.2%), followed by TRPS1 (89.5%), MG (43.9%), GCDFP-15 (21.1%), and SOX10 (3.5%). All GATA3-positive cases showed intermediate to high expression. Comparatively, TRPS1 showed more variability in staining extent and intensity. In 13 (22.8%) cases, TRPS1 showed extensive background staining of inflammatory and mesothelial cells. Of six TNBCs, GATA3, and TRPS1 were positive in six (100%) and four (66.7%) cases, respectively.

CONCLUSIONS

While TRPS1 shows a lower detection rate for MBC than GATA-3, using a combination of these markers can enhance effusion cytology's performance in detecting MBC. However, variability in TRPS1 staining intensity and high background TRPS1 staining of inflammatory and mesothelial cells can increase difficulty in its evaluation.

TRPS1, a New Promising Marker for Assessment of Distant Metastatic Breast Cancer

This article reviewed the identification of breast cancer in the distant metastatic setting through traditional immunohistochemical markers, such as mammaglobin and GATA3, compared with the novel immunohistochemical stain, Trichorhinophalangeal syndrome-1 (TRPS1). We review previous studies evaluating TRPS1 staining, which were conducted using cytology specimens, as well as our recently conducted study evaluating this stain using surgical tissue samples, both from primary and distant metastatic invasive breast carcinoma. In summary, although no immunohistochemical stain is 100% specific or sensitive, in the metastatic setting where tissue available for ancillary studies is limited, TRPS1 was a reliable and even a standalone marker for breast origin, particularly in cases of triple-negative breast cancer.

TRPS1 outperforms GATA3 in pleural effusions with metastatic breast carcinoma versus mesothelioma

INTRODUCTION

In evaluating malignant pleural fluid cytology, metastatic adenocarcinomas and mesotheliomas are often differential diagnoses. GATA binding protein 3 (GATA3) has historically been used to confirm metastatic breast carcinomas; however, GATA3 has low specificity if mesothelioma is included in differential diagnoses. Trichorhinophalangeal syndrome type 1 (TRPS1) protein is expressed in all types of breast carcinomas, with reported high specificity and sensitivity. We investigated the performance of TRPS1 immunohistochemistry (IHC) and compared it to GATA3 in pleural fluids diagnosed with metastatic breast carcinoma and mesothelioma.

METHODS

Thirty-six consecutive ThinPrep pleural fluids and 4 pleural fine needle aspirations (FNAs) with diagnoses of metastatic breast carcinoma (21) and mesothelioma (19) were retrieved, and IHC with TRPS1 and GATA3 was performed on all. Immunoreactivity scores for TRPS1 were calculated by multiplying percentage of immunoreactive cells by staining intensity. Immunoreactivity scores were negative if 0 or 1, low positive if 2, intermediate positive if 3 or 4, or high positive if 6 or 9. Nuclear immunoreactivity of ≥10% with at least moderate intensity was judged GATA3 positive.

RESULTS

GATA3 showed immunoreactivity in all metastatic breast carcinomas and 84% of mesotheliomas. TRPS1 was immunoreactive in all breast carcinoma cases (18 with a score of 9 and 3 with a score of 6). TRPS1 showed low positivity in 5% of mesothelioma cases with all other cases being negative.

CONCLUSION

When cytomorphologic differential diagnoses of mesothelioma exist, TRPS1 is a more specific marker than GATA3 for confirmation of metastatic breast carcinoma in pleural fluid cytology.