RÉSUMÉ
Objective: To investigate the expression of TRPS1 in salivary gland-type breast carcinoma and its clinical application. Methods: A total of 30 cases of salivary gland-type breast carcinoma diagnosed from May 2015 to November 2022 at the Department of Pathology of the First Affiliated Hospital of Nanjing Medical University were collected. The expression of TRPS1 was detected by immunohistochemistry and compared with that of GATA3. TRPS1 and GATA3 expression in 24 cases of primary salivary gland carcinoma. Results: There were 10 cases of breast secretory carcinoma, aged 21-61 years (median 53.5 years), with the size ranging from 0.9-2.2 cm (median 1.6 cm), 2 of which were accompanied by axillary nodal macrometastasis. All patients were alive after 2-55 months of follow-up (median 29.5 months, mean 29.7 months). There were 20 cases of breast adenoid cystic carcinoma, aged 36-77 years (median 53.5 years), with the size ranging from 1.2-5.5 cm (median 2.5 cm), 3 of which were accompanied by axillary nodal macrometastasis. All patients were alive after 3-92 months of follow-up (median 22.5 months, mean 31.7 months), and 1 patient had lung metastasis 15 months after surgery. The medium/high expression ratio of TRPS1 in breast secretory carcinoma was 10/10, which was higher than that of GATA3 (7/10). TRPS1 was also positive in the 2 cases with lymph node metastases. The medium/high expression rate of TRPS1 in breast adenoid cystic carcinoma was 20/20, which was significantly higher than that of GATA3 (2/20). TRPS1 was highly expressed in both classic and solid subtypes, while GATA3 was only expressed in a few cases of the classic subtype. TRPS1 was also positive in 3 cases with lymph node metastases and 1 case of the pulmonary metastases. The expression level of TRPS1 was the same in 1 case before and after neoadjuvant chemotherapy. In addition, TRPS1 was positive in parotid secretory carcinoma and adenoid cystic carcinoma. The medium/high expression rate of TRPS1 in parotid secretory carcinoma (6/6) was higher than that of GATA3 (2/6), and the medium/high expression rate of TRPS1 in parotid adenoid cystic carcinoma (17/18) was higher than that of GATA3 (2/18). Conclusions: The expression of TRPS1 is highly sensitive to salivary gland-type breast carcinoma, especially in GATA3-negative solid subtype of adenoid cystic carcinoma, which plays an important role in clinical practice.