TTF1 and adenocarcinoma: As for the relationship between TTF-1 expression and subtypes, among adenocarcinomas with negative TTF-1 expression, the major subtype was acinar-predominant adenocarcinomas (28.6%), followed by invasive mucinous (27.8%) and papillary (18.3%) subtypes while acinar (40.9%), papillary (31.7%) and minimally invasive adenocarcinoma (7.5%) were in the majority among adenocarcinomas with TTF-1+ (Table 1).