Aims Microvessel density (MVD), proliferating MVD (pMVD) and vascular proliferation index (VPI) are methods used to quantify tumour vascularity in histopathological sections. In this study, we assessed MVD, pMVD and VPI in non-luminal subtypes of breast cancer. Differences between subtypes were studied, and the prognostic value of each method was assessed.
Methods All non-luminal subtypes (61 basal phenotype (BP), 60 human epidermal growth factor receptor 2 (HER2) type and 30 five negative phenotype (5NP)) were selected from a series comprising 909 cases of breast cancer. Sections were stained for Ki67 and von Willebrand factor. Associations between MVD, pMVD and VPI, molecular subtypes and prognosis were studied.
Results MVD was highest in 5NP (Δ54.3 microvessels/mm2 compared with BP, 95% CI 30.3 to 78.3), whereas no clear difference was found between HER2 type and BP (Δ8.8 microvessels/mm2, 95% CI −9.6 to 27.1). pMVD and VPI did not differ between subtypes. For MVD, HR was 1.07 (95% CI 1.03 to 1.11) per 10 vessel increase and 1.9 (95% CI 1.2 to 3.1) if MVD was greater than median value. High MVD was associated with poor prognosis in the HER2 type (HR 1.07 (95% CI 1.02 to 1.12)) and 5NP (HR 1.13 (95% CI 1.03 to 1.23)), but not in BP (HR 1.04 (95% CI 0.94 to 1.14) per 10 vessel increase). pMVD and VPI were not associated with prognosis.
Conclusions MVD appears to be an independent prognostic factor in HER2 and 5NP subtypes of breast cancer, where high MVD is associated with poor survival. MVD was higher in the 5NP compared with both BP and HER2 type.
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Handling editor Cheok Soon Lee
Contributors All authors have actively contributed to this paper. AMB: design and writing the article. Hotspot selection. Interpretation of results. SO: writing the article. Guidance in statistical analyses. Interpretation of results. MRK: design and writing the article. Hotspot selection. Vessel counting. Statistical analyses. Interpretation of results. LAA: training in vessel counting method. Interpretation of results.
Funding The study has received financial support from the Norwegian University of Science and Technology (NTNU) and from the Liaison Committee between the Central Norway Regional Health Authority and NTNU, Trondheim, Norway.
Competing interests None declared.
Ethics approval The study was granted approval including dispensation from the general requirement of patient consent by the Regional Committee for Medical and Health Sciences Research Ethics (REK, Midt-Norge, ref. nr: 836/2009).
Provenance and peer review Not commissioned; externally peer reviewed.
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