Table 2. Tumor expression levels and validated target genes/functions of the eight focus miRNAs.

miRNA	Tumor Level	References	Validated Targets	Validated Biological Functions	References
miR-31	up	[12]–[17], [22], [23], [25], [39]	TIAM1	migration, invasion	[42]
miR-135b	up	[13]–[15], [20], [27], [33]	APC		[26]
miR-137	down	[13], [15], [21], [28]	CDC42	cell cycle, invasion	[29]
miR-133a	down	[12], [15], [21]
miR-215	down	[18], [21]–[23], [37]	TYMS, DTL, DHFR	cell cycle, adhesion, proliferation, chemoresistance	[30], [31], [35], [44], [45]
miR-708	not reported
miR-467d	n.a.*
miR-218	not reported

Expression of microRNAs in human colon tumors compared to normal controls as indicated in corresponding references.

*For miR-467d, no human homolog is known. Differential expression of miR-708 and miR-218 was not reported in the literature. Validated gene targets and biological functions of individual miRNAs are indicated with corresponding references. TIAM, t-cell lymphoma invasion and metastasis 1. APC, adenomatosis polyposis coli. TYMS, thymidylate synthetase. DTL, denticleless protein homolog. DHFR, dihydrofolatereductase. CDC42, cell division cycle 42.