DEC1 (STRA13) protein expression relates to hypoxia-inducible factor 1-alpha and carbonic anhydrase-9 overexpression in non-small cell lung cancer

Differentiated embryo-chondrocyte expressed gene 1 (DEC1) is involved incell differentiation, proliferation, and apoptosis, and was recently shown to be regulated by hypoxia. The present immunohistochemical study demonstrates extensive nuclear expression of the protein in 38% of a series of 115 non-small cell lung carcinomas using a polyclonal antibody (Ab) recognizing DEC1 protein. Such expression was directly related to the expression of two hypoxia-regulated proteins, namely the hypoxia-inducible factor (HIF) 1 and carbonic anhydrase-9. Although DEC1 was not related to angiogenesis or to the expression of VEGF and thymidine phosphorylase, a direct association with up-regulated bFGF receptors was noted. DEC1 was persistently expressed in the nuclei of normal bronchial and alveolar tissue. It is suggested that loss of DEC1 expression is an early event in the development of lung cancer, while DEC1 gene expression occurs in a subset of tumours and parallels the overexpression of other hypoxia-regulated proteins.