<unk>  is the situation where tumor cells have been deprived of oxygen.<unk>  tumor cells usually resist to radiotherapy and chemotherapy  as they can be made more susceptible to treatment by increasing the amount of oxygen in them, but bioreductive prodrugs play a significant part in dealing with this kind of cells: they can kill the oxygen-deficient tumor cells selectively as<unk>  cytotoxins. Study of tumors in such conditions was pioneered by Dr L. H. Gray.
It can also be a result of the high degree of cell proliferation undergone in tumor tissue, causing a higher cell density, and thus taxing the local oxygen supply.
Tumor hypoxia
Vascular tissue neoplasm
Venous stasis
Encephalopathy causes
Bone marrow suppression
Carcinogenesis
Clubbing causes
Tumor embolism