CXCR4 and cancer: Majority of aberrantly expressed miRs targeting CXCR4 in a wide range of cancers are tumor suppressors, for example, in CRC miR-126 [85,143,144,145], miR-133b [146], miR-193a-5p [147], and miR-622 [148] are tumor suppressors, whereas miR-125b is the only overexpressed onco-miR [149].