PCNP and lung adenocarcinoma: Notably, PCNP (PEST-containing nuclear protein) has been shown to promote proliferation, migration, and invasion in lung adenocarcinoma by activating p-STAT3 and p-STAT5 signaling, while also suppressing apoptosis—suggesting that its downregulation by SKD may contribute to the observed anti-migratory effect in this cell line [45].