Interestingly, neither TTF-1 nor Napsin A showed a homogenous staining pattern (i.e., the same percentage of positively stained tumor cells) across the TMA cores: the 16 cases that were diagnosed as TTF-1-positive contained 98 cores available for analysis and only 35 (35.7%) showed positive stained tumor cells. The gene discussed is NAPSA; the disease is neoplasm.