We found that PRKACB (key molecule in cAMP signaling), p‐ERK/ERK (key molecules in MAPK signaling), and Rap1b (key molecule in Rap1 signaling) were upregulated through RAC3 overexpression in HCC cells, which could be inhibited by NNMT knockdown (Figure 5L). Here, PRKACB is linked to hepatocellular carcinoma.