SPP1 and neoplasm: Some studies also showed that SPP1 contributed to tumor cell migration, invasion and survival through PI3K-Akt (Fong et al., 2009; Zhang et al., 2014; Wei et al., 2018) and STAT3 (Behera et al., 2010) signaling, and could also promote tumor growth and metastasis by inducing angiogenesis (Dai et al., 2009; Wang et al., 2011).