The amplified products were subjected to agarose gel electrophoresis, and six samples all gave clear bands in the correct region indicated by the marker, confirming that the six predicted six-HRGs (STC1, PFKL, HK1, PDK3, SLC2A1, XPNPEP1) were all expressed in lung adenocarcinoma A549 cells (Fig. 8G). The gene discussed is XPNPEP1; the disease is lung adenocarcinoma.