β2-AR expression correlated positively with PNI in SACC tissues.
Notes: (A) β2-AR was strongly expressed in both nerve fibers and adjacent tumor cell membranes in SACC tissues with PNI (invaded tumor cells are indicated by red arrowheads). (B) β2-AR was weakly expressed in SACC tissues without PNI. (C) Negative β2-AR expression in SACC tissues without PNI. (D) β2-AR was mainly expressed on the cellular membranes of salivary ducts in NSG tissues. (E) Quantitative comparison of the mean density (IOD/area) of β2-AR expression in PNI SACC tissues, non-PNI SACC tissues, and NSG tissues. Left, quantification of β2-AR-expressing mean density in PNI SACC tissues (n=31), non-PNI SACC tissues (n=7), and NSG tissues (n=24). Each bar represents the mean density of β2-AR expression observed in three to five fields obtained from SACC or NSG tissue. Right, mean β2-AR expression densities in PNI SACC tissues, non-PNI SACC tissues, and NSG tissues. Original magnification, 400×; scale bar =50 μm. *P<0.05. The error bars indicate the SD.
Abbreviations: β2-AR, β2-adrenergic receptor; IOD, integrated optical density; NSG, normal salivary gland; PNI, perineural invasion; SACC, salivary adenoid cystic carcinoma.