Immunostaining was performed using antibodies against IKKα (NB100-56704) IKKβ (Novus Biologicals, Cambridge UK); IKKα (H00001147-M04) (Abnova, Taiwan); IKKα (sc-7182), P-IKKα/β (Ser 180/Ser 181)-R (sc-23470-R), Maspin, p65 (Santa Cruz Biotechnology, Inc. Heidelberg, Germany); CD31, E- Cadherin, Integrin-α6 (BD Bioscience, NJ, USA); p52 (Abcam, Cambridge, UK). Sections were incubated with a biotinylated secondary antibody, and then with streptavidin conjugated to horseradish peroxidase (DAKO A/S, Glostrp, Denmark). Antibody localization was determined using 3,3-diaminobenzidine (DAB) (Vector Laboratories; Burlingame, CA, USA).
A pressure cooker with DAKO target retrieval solution ph9.0 (DAKO) was employed for Maspin, mouse IKKα, human IKKα, P-IKKα/β, IKKβ and E- Cadherin detection. Staining with p52, p65, Integrin-α6 and CD31 antibodies was performed in cryosections of tumors.