Fig. 2.

Vascular density of stromal sub-compartments. A: Juxtatumoral stroma (within 100 μm of tumour tissue) and panstroma (the rest of the tumour stroma) were defined using the Ariol™ software to perform separate analyses for vascular density. Scale Bar = 100 μm. B, C: The micro-vascular density (MVD, D) was measured by number of vessels/mm². The total vascular area (TVA, E) was measured by area occupied by vessels per 1000 units of area using automated Ariol™ analysis for the stromal cub-compartments areas of PDAC. The summary data are shown in the form of box (median and interquartile ranges) and whisker (95% range) graphs. Each data-point represents a measurement from individual core. In case of multiple spots analysed within the same core (for Juxtatumoral only) the median of the index measurement per core was used. Statistical analyses were performed by Kruskal-Wallis test with Dunn's post-hoc multiple comparison. ns, not significant, *p < 0.05, **P < 0.01, ***p < 0.001. D: The dimension of each vessel was measured. The summary data are shown in the form of box (median and interquartile ranges) and whisker (95% range) graphs. Each data-point represents a vessel (number, n=) on a graph with logarithmic Y-axis scale. Statistical analysis was performed by Kruskal-Wallis test with Dunn's post-hoc multiple comparison. **P < 0.01, ***p < 0.001. E. The proportion of capillaries (5.5–20 μm) is the highest in normal tissue, whereas in tumour stroma arteries (100–500 μm) and arterioles (20–100 μm) are more prevalent. In juxta-tumoral stroma very small capillaries (<5 μm) account for 3–4% of total and may represent non-functional vessels compressed by the dense stroma.