CHRNA7 and breast cancer: The ERK/MAPK and JAK2/PI3K signaling cascades in breast cancer cells can be activated by α7-nAChR activation (Chen et al., 2006; Nishioka et al., 2011; Kalantari-Dehaghi et al., 2015), while α9-nAChR overexpression is observed in tumor tissues compared with adjacent normal tissues (Lee et al., 2010).