SLC25A3 and neoplasm: He later expanded the model to identify two causes that could lead to the development of a hypertumour within the original tumour: insufficient angiogenesis leading to the 'hijacking' of existing vascular infrastructures within the tumour by cells that themselves produce insufficient amounts of tumour angiogenic factors 70, and an increased demand for phosphorus, leading to an up-regulation of phosphate transport proteins and, thus, upregulated ribosome biogenesis 107.