Relationship of vascular maturation in breast cancer blood vessels to vascular density and metastasis, assessed by expression of a novel basement membrane component, LH39

Abstract

Angiogenesis, the formation of new vessels, has been demonstrated to be an indicator of prognosis in breast cancer patients. The extent of differentiation of the tumour vessels may affect access of peripheral white cells and egress or invasion of tumour cells. This has not been assessed in relation to tumour microvessel density or other variables and may be a marker of vascular remodelling. LH39 is a monoclonal antibody recognizing an epitope located at the lamina lucida of mature small veins and capillaries but not in newly formed vessels. To study vascular differentiation in breast tumours, we examined the vascular maturation index (VMI) in 12 normal and 50 breast carcinomas and this was correlated with different clinicopathological variables including angiogenesis. Mature vessels were defined by staining with antibodies to both LH39 and to CD31, using double immunohistochemistry, whereas immature vessels stained only for CD31. VMI was defined as the % fraction of mature vessels (LH39-positive) / total number of vessels (CD31-positive). The VMI was significantly higher in normal (54–68.5%; median 66.5%) than in tumours (0–47%; median 8.8%) ( P = 0.0005). There was a significant inverse correlation between the tumour VMI and nodal status (Fisher's exact test, P = 0.01) and between high VMI and low thymidine phosphorylase (TP) expression (Mann–Whitney U -test, P = 0.01). No significant association between VMI and tumour size, oestrogen receptor, epidermal growth factor receptor, grade, angiogenesis, patient age, or E-selectin was seen. There was a significant reduction in relapse-free survival ( P = 0.01) with high angiogenesis. These findings show that the VMI gives new information on the mechanism of tumour angiogenesis independently from microvessel quantitation, there is a wide variation in the differentiation of tumour vasculature but the degree of capillary differentiation is not associated with quantitative angiogenesis. The VMI identifies a subset of patients who have a high chance of regional node involvement. © 2000 Cancer Research Campaign

Vascular phenotype in angiogenic and non-angiogenic lung non-small cell carcinomas

“…In all the cases classified as angiogenic we have confirmed that most of the vessels have an immature phenotype, with deficient LH39 expression, as observed previously in oral carcinoma (Almeida et al, 1992b), breast carcinoma (Kakolyris et al, 2000), and another series of n-SCLC (Kakolyris et al, 1999). It should be noted that a variable number of mature vessels is still present.…”

“…These data suggest that the detection of LH39 allows the discrimination between mature and recently formed vessels. Most of the intra-tumoural vessels should therefore be negative for LH39 and three studies, on oral carcinomas (Almeida et al, 1992b), on breast carcinomas (Kakolyris et al, 2000) and on lung cancer (Kakolyris et al, 1999) have confirmed this hypothesis. Even in the case of breast cancer, the number of LH39-negative intra-tumoural vessels is significantly higher than in normal breast tissue (where some LH39 negative, immature vessels are present because of the physiological remodelling of the tissue).…”

“…This molecule is expressed on the basal membrane of capillaries and small venules in a variety of normal human tissues but it is absent in small vessels present in pyogenic granulomas or nonspecific oral ulceration (Almeida et al, 1992a,b). Furthermore, Kakolyris et al (2000) have demonstrated that in normal breast tissue (an organ in which remodelling occurs physiologically) a proportion of the vessels is LH39 negative. These data suggest that the detection of LH39 allows the discrimination between mature and recently formed vessels.…”

Vascular disrupting agents in clinical development

“…Indeed, tumour vasculature is, among others, marked by a high rate of endothelial cell proliferation, the absence of pericytes, abnormalities in the basement membrane and often an increased vascular permeability. Structurally, disorganised, tortuous, thinwalled vessels are seen that lack smooth muscle and pericyte coats and innervation (Figure 1) (Kakolyris et al, 2000;Konerding et al, 2001). Blood flow frequently is sluggish and at times might be stationary or even in a reversed direction (Tozer et al, 1990).…”

Angiogenesis: An update and potential drug approaches (Review)

“…These differences could be exploited by selective drugs or agents, now called vascular disrupting agent (VDAs) or vascular targeting agents (VTA) (94). Several reports have shown that biological differences between normal and tumor vascular endothelium (Table II) can provide a scientific rationale for vascular targeting and therapeutic benefits (37,(94)(95)(96)(97)(98)(99)(100)(101). Multiple tumor endothelial markers that are not expressed on normal vascular endothelium are now being characterized and used for specific targeted purposes (97).…”