Colorectal cancer: The epigenetic role of microbiome

Table 2 A list of representative miRNAs identified in tumor tissues that are of prognostic value in CRC patients

miRNA	Role in CRC	Ref.
miR-15a/miR-16	Their low expression levels were associated with poor disease-free survival and overall survival	[124]
miR-17-5p	Its high expression was associated with disease-free survival	[125]
miR-21	Its high level of expression was associated with poor survival and poor therapeutic outcomes	[126]
miR-29a	Its elevated level of expression was associated with a longer disease-free survival in stage II CRC patients	[127]
miR-34a-5p	Its high expression was correlated with disease-free survival	[128]
miR-106a	Its downregulation was associated with shortened overall survival	[125]
miR-132	Its decreased expression level was associated with poorer overall survival and occurrence of distant metastasis especially in liver	[129]
miR-150	Its elevated expression level was associated with longer overall survival. While its low level of expression was associated with poor therapeutic outcome in patients treated with 5-Fluro uracil	[130]
miR-195	Its low expression rate was associated with occurrence of lymph node metastasis and advanced tumor grade/stage	[131]
miR-199b	Increased in metastatic CRC tissue compared with non-metastatic CRC tissue. Furthermore, its low expression was associated with longer overall survival	[132]
miR-203	Its elevated expression level was associated with advanced TNM staging and poorer overall survival	[130]
miR-320e	Its high expression was associated with poorer overall survival in stage III colon cancer patients	[133]
miR-429	Its overexpression was associated with overall survival; low level of expression was associated with response to 5-Fluro uracil-based chemotherapy	[134]
miR-494	Its elevated expression was associated with shorter DFS and overall survival	[135]
miR-625-3p	High expressions were associated with higher overall survival and enhanced response to therapy	[136]

CRC: Colorectal cancer.