Fig. 2

Immunohistochemical staining of IRX3 and its correlation to the circulating promoter methylation level. A Quantification of IRX3 positive area. Compared to the group of circulating IRX3 promoter methylation above the median (gray), the group of circulating IRX3 promoter methylation below the median (black) showed a higher amount of IRX3 positive stained area. B Correlation analysis between circulating IRX3 promoter methylation and the amount of IRX3 positive stained area revealed a significant inverse correlation (r = − 0.66) C Correlation analysis between cardiac fibrosis and the amount of IRX3 positive stained area showed no significance for the correlative tendency. D Immunohistochemical staining of IRX3 (red color) in a cardiac biopsy of a patient from the low circulating IRX3 promoter methylation group showing a high amount of IRX3. E Immunohistochemical staining of IRX3 (red color) in a cardiac biopsy of a patient from the high circulating IRX3 promoter methylation group showing a low amount of IRX3. Student’s t-test was used for single comparison. IRX3 positive area and associated error bars represent mean ± SEM, n = 5