AREG and neoplasm: Single-cell RNA sequencing revealed tumor-infiltrating myeloid populations, including apolipoprotein C-positive (APOC+) macrophages, which interact with tumor cells via the amphiregulin-epidermal growth factor receptor (AREG-EGFR) axis, activating MAPK/extracellular signal-regulated kinase (ERK) signaling to promote tumor growth and immune modulation.