Table 1. Indirect characterization of the microenvironment in each layer of a tumour cord.

	Normoxic cells	Hypoxic cells
		HIF-1-positive	Pimonidazole-positive
Distance from blood vessel	Close	Far	Extremely far
HIF-1α expression	−	+	−
Pimonidazole staining	−	−	+
Luciferase-tagging	−	+	−
Glucose-availability	+	+	−
Oxygen concentration	>> 1%	1–3%	< 1%
Proliferation	+	+	−
Radioresistance	Very low	Low	High
Contribution to recurrence	−	−	+++