PCP4 and lung adenocarcinoma: In another experiment, we identified three specific genes associated with the prognostic signature: TCN1, DIRAS3, and IZUMO4. A prognostic model for lung adenocarcinoma based on eight genes (TCN1, COL1A1, SPOK2, PCP4, S100P, CAV2, GPX3, and ASPM) has been previously constructed (Tu et al., 2021).