GPNMB and neoplasm: Interestingly, in a scRNAseq study of murine NASH livers, proliferating macrophages were predominantly co-expressing Trem2, Gpnmb and Spp1. (Zhang et al., 2022) Spp1 encodes the protein osteopontin (OPN), which is also involved in tumor promotion and predicts a poor outcome in HCC.