Formalin-fixed paraffin-embedded (FFPE) slides of SACC biopsies (4-mm thick) from patients and normal HSG tissue sections were used for IHC staining according to a protocol described previously (25 (link)). Antibody binding was visualized using a Vectastain® Avidin-Biotin Complex kit (cat. no. PK-4001 [rabbit immunoglobulin G (IgG)] or PK-4002 (mouse IgG); Vector Laboratories, Inc., Burlingame, CA, USA) and a Diaminobenzidine kit (cat. no. DAB-1031, Fuzhou Maixin Biotech Co., Ltd., Fuzhou, China), according to the manufacturer's protocol, and counterstained with hematoxylin. Images of the slides were captured using a BX43 light microscope (Olympus Corporation, Tokyo, Japan) controlled with CellSens software (version 1.12; Olympus Corporation). The primary antibodies used for IHC were mouse anti-WDR66 (1:200; cat. no. ab83694; Abcam, Cambridge, UK) and mouse anti-PTEN (1:200; cat. no. 18-0652; Zymed; Thermo Fisher Scientific, Inc.). The quantitative analysis of IHC staining followed the criteria we have described previously (24 (link)). The staining index was determined as follows: 0–2, low (−); 3–6, medium (+); 7–9, high (++) expression.