SPP1 and triple-negative breast carcinoma: In our study, immunohistochemistry (IHC) was performed using a primary mouse anti-human SPP1 monoclonal antibody (osteopontin/OPN/SPP1 antibody, AKm2A1; sc-21742, Santa Cruz Biotechnology, Inc.), which has previously been utilized in the immunohistochemical evaluation of osteopontin expression in triple-negative breast cancer, as described by Niedolistek et al. (2020) [22].