KRAS and colorectal carcinoma: Six studies utilised the 4-biomarker strategy of KRAS, methylated BMP3, methylated NDRG4, and faecal haemoglobin (including β-actin as reference gene) with stool samples, showing overall CRC sensitivities of 81.5–98.1% with specificities of 89.0–94.4% [31, 37, 39, 48, 57, 64, 65].