MRC1 and neoplasm: Macrophage activation plays a major role in the IL6‐activated PMN.[33] We examined the expression of the macrophage activation marker CD206 in paraffin sections of lung tissues using immunohistochemistry and found that CD206 was highly expressed in metastatic foci (Figure 5G), suggesting that the highly secreted IL6 after fibroblast activation induced by the exosomal PIK3CAH1047R mutation in vivo might activate macrophages in the distal organs to promote the formation of PMN for targeted metastasis of disseminated tumor cells.