Neuroendocrine tumours are uncommon tumours which have a diverse biology. This book focuses on two aspects of neuroendocrine tumour biology, firstly identification of novel biomarkers in the diagnosis of neuroendocrine tumours. Secondly, examining receptor expression in neuroendocrine tumours, which may aid diagnosis and offer insight into tumour volume. Two dimensional gel electrophoresis and mass spectrometry was used to identify novel biomarkers in the patient serum and neuroendocrine cell lines. Receptor studies were performed in neuroendocrine tumour patients using immunohistochemistry and positron emission tomograhy.