Solid tumors such as breast cancer have intratumoral regions of low oxygen tension, which influence a vast array of cellular responses. Hypoxia-Inducible Factor 1-alpha (HIF1α) represents the principal transcription factor orchestrating cellular responses to hypoxic conditions, mediating the regulation of genes implicated in oxygen homeostasis. The nucleolus is central stress response hub in the cell, as such we sought to identify novel binding partners of HIF1α in the nucleolar compartment during hypoxic stress.