MEG3 and breast cancer: Although it has been found that miR-506 has the ability to repress IQGAP1 and MAPK signaling pathway to influence breast cancer metastasis, other downstream targets may exist, which prompted us to search by bioinformatic prediction and for the first time, find out SP1 and SP3 as a direct target of miR-506 [29], thereby regulating breast cancer metastasis via DNMT1/MEG3 axis.