Regulation of tissue oxygen homeostasis is critical for cell function, proliferation and
survival. Evidence for this continues to accumulate along with our understanding of the
complex oxygen-sensing pathways present within cells. Several pathophysiological disorders
are associated with a loss in oxygen homeostasis, including heart disease, stroke, and
cancer. The microenvironment of tumors in particular is very oxygen heterogeneous, with
hypoxic areas which may explain our difficulty treating cancer effectively. Prostate
carcinomas are known to be hypoxic. Increasing levels of hypoxia within prostatic tissue is
related to increasing clinical stage, patient age and a more aggressive prostate cancer.
Several researches indicated that hypoxia might also play a role in esophageal cancer. In
glial brain tumors, hypoxia is correlated with more rapid tumor recurrence and the hypoxic
burden in newly diagnosed glioblastomas is linked to the biological aggressiveness. In brain
metastases CA-IX expression (a marker for hypoxia) is correlated to the primary non-small
cell lung carcinomas. Hypoxia enhances proliferation, angiogenesis, metastasis,
chemoresistance and radioresistance of hepatocellular carcinoma. The hypoxic markers HIF-1α,
VEGF, CA-IX and GLUT-1 were all over expressed in colorectal cancer and its liver metastases.
Based on literature, hypoxia in tumors originating or disseminated to prostate, esophagus,
brain and rectum cancer will be studied in this trial.