EXPRESSION OF ANDROGEN RECEPTOR, GROSS CYSTIC-DISEASE FLUID PROTEIN, AND CD44 IN SALIVARY DUCT CARCINOMA

Salivary duct carcinoma (SDC) is an infrequent, aggressive tumor with a histologic similarity to ductal breast carcinoma It must be differen tiated from breast metastasis and other high-grade salivary tumors wit h glandular differentiation. Its histologic similarity to breast carci noma raises the possibility that hormonal manipulation might also be o f use in its treatment. Little is known concerning its pathogenesis. E xpression of variant isoforms of CD44, a transmembrane molecule involv ed in cell-matrix interactions, confers metastatic potential on carcin oma cells in animal models and might also be important in the clinical progression of some human tumors. To address these diagnostic, therap eutic and pathogenetic issues, we performed an immunohistologic study on formalin-fixed, paraffin-embedded sections of 12 SDCs (7 from men, 5 from women), using antibodies to androgen receptor (AR), estrogen re ceptor (ER), progesterone receptor (PR), gross cystic disease fluid pr otein (GCDFP-15), CD44s, and CD44v6, A mucicarmine stain was also perf ormed in each case. Luminal and focal intracellular mucin positivity w as observed in 11 of the12 tumors, There was strong, diffuse reactivit y far AR in 11 of 12 and of GCDFP-15 in 12 of 12, and nonreactivity fo r ER and PR in 12 of 12, CD44s was negative (9 of 12) or only focally positive (3 of 12), and CD44v6 was diffusely positive in 12 of 12, Our study shows that most SDCs have luminal and focal intracellular mucin ; that the immunophenotype AR+/ER-/PR-/GCDFP+ in a malignant salivary tumor with an intraductal (irt situ) pattern is characteristic of SDC but does not completely exclude metastasis from the breast, which migh t also be AR+ and ER/PR- in a lesser proportion of cases; that enhance d expression of CD 44v6 might be an indication of its link to tumotige nesis; and that uniform AR expression raises the possibility that anti androgen therapy might have a role in the management of patients with disseminated disease.