SPP1 and neoplasm: Peinado et al. (2008) also showed that high LOXL2 expression was associated with reduced survival of patients with NSCLC. SPP1, also known as OPN, is a pleiotropic chemokine involved in the induction of tumor metastasis (Shi and Wang, 2017). In various types of cancer, elevated serum SPP1 levels are frequently detected in patients with metastatic cancer (Chiou et al., 2019). Advanced or metastatic LUAD patients with lower SPP1 levels had significantly superior OS and PFS compared with patients with higher levels (Mack et al., 2008).