Does hypoxia-inducible factor 1 alpha expression increase during colorectal carcinogenesis and tumor progression?
We conclude that HIF-1alpha expression occurs in early stages of colorectal carcinogenesis and achieves a maximum in the invasive stage independent of the metastatic status. Perinecrotic activation of HIF-1alpha in invasive tumors underlines a dual role of HIF-1alpha by regulating both pro-survival and pro-death processes. HIF-1alpha up-regulation in response to LPS-mediated stimulation and periinflammatory expression in invasive carcinomas suggest its involvement in inflammatory events. These patterns of HIF-1alpha inducibility could contribute indirectly to the acquisition of a metastatic phenotype.
Published evidence is sparse but does not support the use of radiation therapy in induction regimens for stage IIIA (N2). Given the potential disadvantages of adding radiation preoperatively, clinicians should consider using this treatment strategy only in the context of a clinical trial to allow better assessment of its effectiveness.