This finding is consistent with other studies showing HIF-1α was not expressed in normal tissue but seen at an increasing level during the pathological process of cancer development, progression and loss of differentiation (Zhong et al, 1999), and that staining increased in breast (Bos et al, 2001), skin (Costa et al, 2001) and cervical (Acs et al, 2003) carcinogenesis. This evidence concerns the gene HIF1A and cancer.