TP63 and squamous cell carcinoma: Pathological confirmation of LUAS requires strict WHO criteria: (1) morphologically distinct glandular/squamous components via hematoxylin-eosin staining; (2) immunohistochemical validation (e.g., TTF-1/napsin A for adenocarcinoma, p40/p63 for squamous carcinoma); and (3) spatial segregation of components (each ≥10% tumor volume).