CD8A and salivary duct carcinoma: A higher CD4+ expression compared with CD8+ TIL (CD4/CD8 ratio up to 10:2) was found to be associated with a better prognosis in the salivary duct carcinoma (52), despite this disproportion having no evidence in other SGC histologies that are usually defined by a general predominancy of CD8+ T cells (53, 54).