The elevated level of HIF-1α in the perimeter of 100 mm3 tumors developed from hypoxic cells is less likely due to lower oxygen relative to the core (as it is probable that the perimeter is more vascularized) and more likely due to oxygen-independent factors, cell stressors, oncogenes, and tumor suppressors that characterize cancer and up-regulate HIF. Here, HIF1A is linked to neoplasm.