KLF4 and colorectal carcinoma: To validate the reliability of the microarray test,6 up-regulated miRNAs (mir-21, mir223, mir224, mir29a, mir29b, and mir27a) and their 4 down-regulated target mRNAs (SFRP1, SFRP2, RNF138, and KLF4) were selected for qRT-PCR examination in 40 matched CRC/normal mucosa tissues whose clinical data were listed in Additional file 1: Table S3.