Vascular endothelial growth factor expression in breast cancer

In order to grow, a tumour must obtain a blood supply. This process is called angiogenesis. It is likely that the better a tumour is able to obtain a blood supply, the faster it may grow and the more access the cells of the tumour may have to the circulation for haematogenous metastasis.Several authors have reported that breast tumours that contain large numbers of blood vessels have a poor prognosis. This suggests that angiogenesis is an important mediator of the behaviour of breast tumours.A protein called vascular endothelial growth factor (VEGF) has been described which is a potent inducer of angiogenesis. It is a specific endothelial mitogen produced by both normal tissues and tumours.Prior to commencement of this thesis the role of VEGF in breast cancer had not been reported. Given the apparent importance of vascularity to prognosis in breast cancer it was hypothesised that VEGF may be of importance in the behaviour of these tumours.The aim of this research was to develop and apply techniques for studying the expression of VEGF in breast cancers. It was hoped that such techniques might be of value identifying a group of patients whose prognosis was poorer than would be expected from conventional predictors such as lymph node status. This would allow the potential for intervention either with specific anti-angiogenic therapy or conventional adjuvant therapy.A part of the cDNA sequence of VEGF was cloned into a plasmid expression vector. The vector was reproduced in bacterial cultures and the presence of the cloned sequence verified by Southern blotting, PCR and DNA sequencingThe vector was then used to produce an RNA riboprobe with a non-radioactive digoxigenin label. Attempts were made to use this probe and a DNA oligonucleotide