Tumor western blot experiments and qRT-PCR validation confirmed that p-MEK/MEK, p-ERK/ERK, and CES1 levels decreased with the knockdown of CHRNA5, whereas nicotine reversed this trend in the SH group, indicating that CHRNA5 regulates CES1 expression through the MEK/ERK pathway. This evidence concerns the gene MAP2K7 and neoplasm.