Am. Schor et al., HETEROGENEITY IN MICROVASCULAR DENSITY IN LUNG-TUMORS - COMPARISON WITH NORMAL BRONCHUS, British Journal of Cancer, 77(6), 1998, pp. 946-951
The aim of this study was to test the hypotheses that (a) microvascula
r density (MVD) measured in histological sections of resected non-smal
l cell lung carcinomas is an index of angiogenesis and (b) the measure
ment of MVD in a single block is representative of the overall MVD of
the tumour. MVD was quantitated in one block per specimen of 60 lung t
umours and nine normal lung tissues, and in 47 blocks taken from diffe
rent regions of four tumours. Blood vessels were stained with antibody
to von Willebrand Factor and MVD was quantitated using two methods: a
verage density throughout the section (a-MVD) and density in the most
vascularized area or 'hot spot' (h-MVD). Similar h-MVD values were fou
nd in tumours and in normal bronchus, whereas a-MVD was greater in the
latter (P < 0.01). When 47 blocks from four tumours were analysed, in
ter-tumour variation was significant (P < 0.001) in spite of significa
nt intra-tumour variation. The highest MVD value was not necessarily f
ound in the periphery of the tumour. The four tumours were ranked into
either two or four tiers according to their overall MVD. In 50 random
selections of one block per tumour, the correct ranking was achieved
in 68-74% of cases with the two-tier ranking and in 6-16% of cases wit
h the four-tier ranking (h-MVD and a-MVD values respectively). These r
esults suggest that elevated MVD values do not necessarily represent a
ngiogenesis in non-small cell lung carcinomas, When only one block per
tumour is examined, the chance of obtaining an accurate estimate of t
he vascularity of that tumour may be lower than 68%.