Heatmap and volcano plot analyses of three datasets demonstrated significant reduction in Hcy catabolism genes, including genes of MTRR, 5‐methyltetrahydrofolate homocysteine methyltransferase (MTR), methylenetetrahydrofolate reductase (MTHFR), methionine adenosyltransferase 1A (MAT1A), and CBS in IPF tissues (Figure 2C,D; Figure S1A–C, Supporting Information). The gene discussed is MTRR; the disease is idiopathic pulmonary fibrosis.