According to the PDC database, compared with normal tissues, SDHA (Figure 9B, p < 2.2×10-16), SDHB (Figure 9C, p = 1.1×10-13), SDHC (Figure 9D, p = 1.2 ×10-10), and SDHD (Figure 9E, p = 0.00028) were low expressed in colon cancer at protein level. Here, SDHD is linked to colonic neoplasm.