Background: Salivary duct carcinoma (SDC) is a rare and aggressive malignancy. Recently, biomarker studies found promising targetable alterations. In this study, we provide a descriptive analysis of tumor and immune biomarkers and survival associations.
Methods: We extracted clinical data and performed immunohistochemistry for AR, AR-V7, HER-2, PD-L1, LAG-3, and tumor-infiltrating immune cells.
Results: We included 17 patients. Age ranged from 42 to 85 years old; HER-2 was overexpressed or amplified in 65%. AR was positive in 88% of patients, while AR-V7 was positive in 13% by IHC. We found low scores of immune infiltration and a PD-L1 expression in 53%. We found no clinically significant association between biomarkers and survival outcomes.
Conclusion: In this small series of SDC, biomarkers do not seem to correlate with disease biology, although they provide additional treatment options. SDC may harbor a different immune profile compared to other subtypes, with an indication of T-cell dysfunction.
Keywords: ErbB-2 receptor; androgen receptor; immunotherapy; salivary gland cancer; tumor microenvironment.
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