RARRES3 up-regulation in Luminal/ER+ may play a role in the anti-motility and anti-metastatic effects of ATRA (Nwankwo, 2002; Terao et al, 2011), as the factor has been shown to suppress metastases to the lung in breast cancer (Errico, 2014; Morales et al, 2014). This evidence concerns the gene PLAAT4 and breast carcinoma.