EYA2 and breast cancer: Our current study provides a molecular explanation linking high EGFR levels in breast cancer with downregulated miR-338-3p and upregulated EYA2, and suggests that the EGFR/miR-338-3p/EYA2 pathway determines breast cancer lung metastasis and that miR-338-3p and EYA2 may be used to identify primary breast tumors with the capacity of metastasis, especially lung metastasis.