On glioblastoma GL261 cells modified with a fluorescent UnaG reporter under the control of HRE (hypoxia response elements) transplanted into mice, it was possible to track the appearance of hypoxic zones and activation of HIF-1, as well as the attraction and migration of tumor-associated myeloid cells and cytotoxic T lymphocytes (CTL) into hypoxic niches for their reprogramming [171]. The gene discussed is HIF1A; the disease is neoplasm.