Angiogenesis in breast cancer: establishing a link between angiogenesis and hormone regulation
© Current Science Ltd 2000
Published: 12 March 2000
Angiogenesis is a process of formation of new blood vessels that is essential for tumour growth and metastasis. There is recent evidence indicating that angiogenesis can be regulated by hormones. The aim of our study was to evaluate the effect of oestrogen in angiogenesis using a hormone-dependent cancer model, breast cancer. We studied two different breast cancer cell lines (one hormone-dependent, MCF7, and one hormone-independent, Hs578T), that were inoculated in the mammary fat pad of nude mice. The mice were treated with oestrogen and the tumours were removed when they reached 80 mm3. Angiogenic index, VEGF and TGFα were evaluated by immunohistochemistry and Western blotting. The MCF7 tumours had a higher microvessel density and expressed both VEGF and TGFα . In contrast, Hs578T, xenografted in mice, presented a lower angiogenic index, expressed VEGF, but did not express TGFα . We also studied a series of 86 human breast carcinomas and demonstrated a significant association between TGFα and angiogenic index: TGFα + cases, 48.1± 28.0; TGFα- cases, 31.8± 20.0 microvessel density (P = 0.01). Since by binding to its receptor, oestrogen induces the transcription of TGFα, our results suggest that TGFα is a putative factor linking hormone regulation and angiogenesis in breast cancer.