AKR1B10 in usual interstitial pneumonia: Expression in squamous metaplasia in association with smoking and lung cancer

The incidence of lung cancer (LC) is markedly increased among patients with usual interstitial pneumonia (UIP), and tobacco smoking is its superimposed risk factor. AKRIB10 (aldo-keto reductase IB10) is frequently overexpressed in pulmonary squamous cell carcinoma and adenocarcinoma in smokers. To investigate the role of AKRIB10 in the pulmonary carcinogenesis in UIP with correlation to tobacco smoking, we examined 13 UIP cases with LC, 13 UIP cases without LC, and 30 cases of non-UIP LC using AKRIB10 immunohistochemistry. AKRIB10 immunoreactivity was confined to squamous metaplasia in honeycomb lesions of UIP and neoplastic cells of LC. Squamous metaplastic foci showed AKR1B10 immunoreactivity more frequently in UIP with LC (24/36 foci, 67%) than in UIP without LC (16/44 foci, 37%) (P<0.01). AKRIB10 expression in UIP was also more frequent in squamous metaplastic foci in smokers (38/67 foci, 57%) than in non-smokers (2/13 foci, 15%) (P<0.01). AKRIB10 expression was frequently observed in both UIP-associated LC (10/13 foci, 77%) and non-UIP LC (18/30 foci, 60%). Ki-67 labeling index was significantly higher in AKRIB10-positive squamous metaplasia of UIP than in AKRIB10-negative squamous metaplasia of UIP. Our results demonstrate that AKRIB10 is involved in the development of LC in UIP in association with smoking. AKR1B10 might be useful as a new marker for identification of high LC risk patients in UIP. (C) 2008 Elsevier GmbH. All rights reserved.