This polarization regulation is dynamically affected by microenvironmental factors: hypoxia inhibits GPX4 transcription through HIF-1α, which enhances ferroptosis sensitivity (192); tumor cells with high SLC7A11 expression block macrophage glutathione synthesis by competitively consuming cystine (177); TAMs secrete IL-6/TNF-α to activate NOX2, which exacerbates ROS accumulation and forms a positive feedback loop of “oxidative stress-ferroptosis” (187). This evidence concerns the gene GPX4 and neoplasm.