On one hand, PAX8 acts primarily as a diagnostic marker to differentiate lung cancers from metastases originating in PAX8-positive tissues (e.g., thyroid, renal, ovarian cancers); on the other hand, PAX9 demonstrates a more direct role in lung cancer progression, particularly in lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC), where it may help in prognostic determination. Here, PAX8 is linked to small cell lung carcinoma.