The activation of α9nAChR by NNK and nicotine forms a significant feedback loop through PI3K-Akt and MAPK signaling, which could further initiate activator protein 1 (AP1) and vitamin D receptor (VDR) transcription factors stimulation to confer to the cancer development [[94], [95], [96], [97]]. This evidence concerns the gene AKT1 and cancer.