Histopathological Features and Tumor Marker Eexpression in Primary Pulmonary Adenocarcinomas

Abstract

Forty cases of surgically-resected primary pulmonary adenocarcinoma (PA) were classified according to our proposed microscopic classification (modified Noguchi's opinion) into three subtypes, C, D and F, and the histopathological features and tumor marker expression were compared between each subtype. Overall, type C was the most frequent subtype, and the mean patient age was lower in the type D group, and higher in the type F group. There was a high proportion of females in the type C group. Histopathologically, the malignant potential of PA appeared to be dependent on tumor size, lymph/venous invasion and lymph node metastasis. Type D PA tended to have a higher malignancy than the other types, with type C having the lowest malignancy. The Ki-67 labeling index was highest in type D and lowest in type C. The TUNEL-labeling index was highest in type C cases, and lowest in type D cases. More type D tumor cells were positive for p53 than the other two subtypes. Therefore the histopathological findings of PA correlated well with tumor marker expression, with the more malignant type D cells showing the highest level of expression of the proliferative marker Ki-67 and accumulation of p53. These results support our proposed classification of PA as a practical and useful procedure to determine the grade of malignancy.