SAA1 and neoplasm: In a colorectal cancer (CRC) model, macrophage-derived IL-1β was shown to elicit the production of serum amyloid A1 (SAA1) by tumor cells, which in a feed-forward manner induced macrophages to upregulate metalloproteinase-9 secretion allowing cancer migration and establishment of metastasis (Sudo et al., 2021) (Figure 2A).