Aims:
To investigate TTF-1-negative pulmonary adenocarcinoma, focusing upon mucin production and the expression of hepatocyte nuclear factor-4 alpha (HNF4 alpha).
Materials and methods:
Two hundred and sixty-two cases of pulmonary adenocarcinoma were examined histologically and immunohistochemically; TTF-1 was expressed in 222 cases (84.7%), and 40 cases (15.3%) were negative. Among TTF-1-negative cases there were 31 mucinous-type tumours, and HNF4 alpha, MUC5AC and MUC2 were expressed in 34 cases (85%), 29 cases (72.5%) and four cases (10%), respectively. In contrast, their expression was rare in TTF-1-positive tumours. A statistically inverse correlation was confirmed between the expression of TTF-1 and that of HNF4 alpha and MUC5AC.
Conclusion:
Most TTF-1-negative pulmonary adenocarcinomas are mucinous lesions with the predominant expressionof HNF4 alpha and MUC5AC.