funded by the Tata Memorial Centre explores the role of peri-operative hypoxia in breast cancer biology. Hypoxia is a consistent feature of most solid tumours with variable incidence and severity. Chronic hypoxia has been well studied and characterized. However, the role of acute hypoxia, especially in the peri-operative setting wherein ligation of blood vessels leads to acute hypoxia in surgically resected tissue, requires elucidation. We are investigating the role of surgery-induced hypoxia during surgical resection of primary breast cancer. We have biopsied patients at different times during surgical intervention and subjected these samples to whole transcriptome sequencing. We identify pathways related to stress, stemness, metastasis, invasion, wound healing, inflammation and immune responses de-regulated due to surgical intervention. We are also using an in-vitro cell line based system to investigate the role of re-oxygenation following chronic and acute hypoxia in tumour cell dissemination and metastasis seeding. The findings from this study were presented at the annual meeting of the American Association for Cancer Research in 2017.