Nicotine exposure induces the augmented expression of  α7-nAChRs, which causes an influx of Ca2+ and activates downstream signals, such as protein kinase C, Raf-1, extracellular-signal regulated kinase (ERK) 1/2, and c-Myc, leading to increases in cell proliferation, cancer cell migration, metastasis, or the inhibition of apoptosis. The gene discussed is CHRNA7; the disease is cancer.