title: Tumour Microenvironment: Overview with an Emphasis on the Colorectal Liver Metastasis Pathway.
abstract: The tumour microenvironment (TME) represents a dynamic network that plays an important role in tumour initiation, proliferation, growth, and metastasis. Cell behaviour may be regulated by interplay of molecular interactions involving positive and negative reinforcement as well as a high level of cross-talk, which determines this system. Additionally, cancer involves cell proliferation, its malignancy defined by the tumour's ability to break down normal tissue architecture and by a dynamic process of invasion and metastasis. The metastatic cascade is regulated by a chain of molecular steps which triggers the progression of the developing cancer cell in the primary tumour into a number of transformations, leading to invasion and proceeding to metastases. Tumour-associated macrophages (TAMs) play a key-role in the progression from inflammatory conditions to cancer; TAMs are also capable of infiltrating the tumour microenvironment. Furthermore, myeloid-derived suppressor cells (MDSCs), a population of inhibitory immune cells, have been reported to increase in various cancer types, although characterising human MDSCs remains difficult, as their phenotype is quite variable. The future of cancer treatment is likely to involve creating more drugs that target these elements as well as others. An overview of the tumour's microenvironment is, therefore, presented in this paper, focusing on the metastatic pathways of primary colorectal cancer to the liver.
authors.affiliation: Barts Cancer Institute, Queen Mary School of Medicine and Dentistry, University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK. alexgiakoustidis@gmail.com.|The London Clinic, 116 Harley Street, London, W1G 7JL, UK. alexgiakoustidis@gmail.com.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Giakoustidis
authors.affiliation: Academic Department of Surgery, The Royal Marsden NHS Trust, Fulham Road, London, SW3 6JJ, UK.|Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, W2 1PG, UK.
authors.forename: Satvinder
authors.initials: S
authors.lastname: Mudan
authors.affiliation: Barts Cancer Institute, Queen Mary School of Medicine and Dentistry, University of London, John Vane Science Centre, Charterhouse Square, London, EC1M 6BQ, UK.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Hagemann
keywords: Colorectal liver metastasis; Myeloid-derived suppresor cells; TAMs; Tumour microenvironment