Similarly, lactic acid, formed by tumor cells as a result of the predominance of anaerobic metabolism, creates a favorable tumor microenvironment by blocking the transcription of the interferon-γ gene, contributing to the weakening of antitumor immunity, inducing HIF-1α to enhance the proliferation of cancer cells, inducing the synthesis of hyaluronan by tumor cells to destroy extracellular matrix, and increasing their metastatic potential [95]. The gene discussed is HIF1A; the disease is neoplasm.