Immunohistochemical Assessment of Peripheral Squamous Lung Cancer: Comparison to Central Squamous Cell Carcinoma and Peripheral Adenocarcinoma

Purpose: Incidence of peripheral squamous cell carcinoma (pSCCs) of the lung has increased over recent years, but the immunohistochemi cal factors involved in pSCCs have not been well established. The aim of this study was to analyze the immunohistochemi cal differences between pSCCs and central-type SCCs (cSCCs), and similarities between pSCCs and peripheral adenocarcinomas (pADCs). Materials and Methods: In this retrospective study, w e investigated the expression of three potential prognostic factors (p53, Ki-67, t-C EA), and tw o potential therapeutic targets (epiderm al growt h factor receptor [EGFR], and c-erbB-2) in 263 surgically resected cases of primary SCC and pADCs of the lung from January 2001 to July 2008. We divided the SCCs between peripheral and central types, and compared the expression rates of markers between pSCCs and cSCCs, and between pSCCs and pADCs. Results: In this study, there were 149 pADC cases, and among the 114 SCC cases, there were 41 pSCCs (36.0%). There were significantly higher expression rates of Ki-67 and EGFR in pSCCs than in cSCCs or pADCs (p=0.003, p=0.039, respectively). Conclusion: We found immunohistochemical differencies in pSCCs from cSCCs and pADCs. (J Lung Cancer 2009;8(2):99 �� 102)