ADCYAP1 and cancer: Based on the application concentration range of PACAP38 in previous research, we first explored how PACAP38 treatment affected the growth activity of cancer cells across a concentration range from 0.1 nM to 200 nM by CCK8 assays (Maugeri et al., 2016; Hajdú et al., 2021; Bensalma et al., 2019).