There is growing evidence that inflammation is a contributing factor leading to cancer development, yet pathways involved in this progression are not well understood. While HIF-1, a heterodimeric transcription factor composed of inducibly expressed HIF-1α and constitutively expressed HIF-1β, regulates genes that play essential roles in tumor progression and HIF-1 activity is up-regulated in inflammatory conditions, there is no prior evidence suggesting a role for HIF-1 as a link between inflammation and the development of cancer. Therefore, we investigated whether the HIF-1 signaling pathway was stimulated by the proinflammatory cytokine interleukin-1 β (IL-1β)-induced inflammatory signal in A549 cells.