Differences in clinicopathological and biological features between central-type and peripheral-type squamous cell carcinoma of the lung

The central type and peripheral type squamous cell carcinoma (SCC) of the lung have different clinicopathological characteristics, but, little is known about their biological characteristics. We investigated differences between the properties and phenotypes of peripheral-type (P-type) and central-type (C-type) SCC by performing an immunohistochemical analysis of each type by tissue microarray analysis with a large panel of antibodies. To examine strictly, we selected 20 P-type SCCs that were pathological stage T1 and limited to more peripherally than the fifth bronchial bifurcation, and 21 C-type SCCs that were pathological stage T1 and limited to a lobar bronchus. The results of the clinicopathological study showed that the patients with P-type SCC were significantly older than the patients with C-type SCC and that squamous metaplasia was predominant in C-type SCC than in P-type SCC. The 36 antibodies revealed different expression patterns of cytokeratin 7 (CK 7) and cytokeratin 19 (CK 19) between C-type and P-type SCC. CK 7 expression was more predominant in P-type SCC than in C-type SCC, and CK 19 expression was more predominant in C-type SCC than in P-type SCC. These results suggest that C-type and P-type SCC have different clinicopathological and biological features.