Several in vivo and in vitro studies have demonstrated that blue light irradiation exerts antimicrobial, anti-inflammatory, and anticancer effects on skin diseases and cancer, such as acne vulgaris (20), breast cancer (21), and colon cancer (22) by regulating miRNAs, ROS, and the mitogen-activated protein kinase (MAPK) signaling pathway. This evidence concerns the gene WNK2 and breast cancer.