Xu B, et al. - Assuming the value of the androgen receptor (AR) immunoexpression as a diagnostic and predictive marker for androgen deprivation therapy (ADT) response in salivary duct carcinoma (SDC), researchers examined a large retrospective cohort of 188 SDCs from 163 patients, including 22 paired primary and metastatic SDCs from the same patients, for AR immunopositivity and staining pattern focusing particularly on staining heterogeneity and concordance. They also examined a control cohort of 61 non-SDC salivary gland carcinomas. Observations revealed a high prevalence of AR immunoexpression in primary and metastatic SDC. In SDC, they observed the cumulative AR immunopositivity rate of 90%. Intratumoral AR heterogeneity and discordant AR expression in metastasis were observed in a small subset of SDC. Non-SDC salivary gland carcinoma had AR immunoexpression uncommonly and usually focal.