Table 2. Vascular volumes in EL-4, progressive E.G7-OVA and regressive E.G7-OVA tumours.

	Tumour type
Stain	EL-4	E.G7-OVA (regressive)	E.G7-OVA (progressive)
Masson's trichrome	0.9±1.5	8.7±5.5a	1.1±1.6
Carmine red	0.7±1.2	8.9±5.3a	1.1±1.7
Factor VIII	0.7±1.4	6.1±4.0a	0.8±1.2
DCE MRI (Gd-DTPA)	2.1±1.2	8.9±2.7a	4.4±1.4b

Tumour sections stained with either Masson's trichrome or an antibody against Factor VIII, or obtained from mice that had been injected with carmine red dye, were observed at × 200 magnification and the resulting images relayed to a computer screen. Vascular volume, as a percentage of tumour volume, was estimated by an axial strip sampling technique, as described in the Materials and Methods section. The data are the mean percentage±s.d. for 90 tumour areas stained with Masson's trichrome, 30 areas stained with antibody against Factor VIII and 90 areas from carmine dye-injected tumours. Three tumours were used in each group. Also given are vascular volumes (as mean percentage±s.d.) determined using dynamic contrast agent-enhanced MRI, as described in the Materials and Methods section. Respectively, three, five and five tumours were used.

^aStatistically significantly different from EL-4 and progressive E.G7-OVA tumours, P<0.01.

^bStatistically significantly different from progressive E.G7-OVA tumours, P<0.05.