Essay On Breast Cancer

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Breast Cancer

In 2016, breast cancer was the commonest diagnosed cancer in women with 17 million cases diagnosed and a resultant 5 million deaths. In the Western world, improved treatments and screening programmes have resulted in a 5-year survival of 80-90% (WHO, 2016). However, a third of breast cancer patients are found to have distant metastases at diagnosis, bringing their 5-year survival rate down by 25% (Siegel et al., 2004). Metastasis occurs when tumour cells travel through the vascular or lymphatic system and grow in distant organs, commonly bone, lung, liver and brain.
Current treatment involves surgical removal of the visible tumour bulk followed by chemo- and radio- therapy targeting distant spread. Breast cancer is
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Tumour Micro-environment

The tumour stroma appears to be a major factor in tumour progression after initial tumour formation (Conklin and Keely, 2007). It initially protects against tumourigenesis; but neoplastic cells cause changes and recruit various other cell lines with a multitude of functions, forming a tumour micro-environment (TME). This is defined as “a heterogeneous population of cells consisting of the tumor bulk plus supporting cells” (Bussard et al., 2006). The tumour cells recruit the stroma cells and cause a reactive phenotype, known as tumor-associated stromal cells (TASCs).
Mesenchymal stem cells, endothelial cells, pericytes, fibroblasts and various other immune cells are all components of the TME,each with specific functions. When activated, they take on a similar in function to those found in inflammation and wound healing and cause fibroblast infiltration, recruitment of immune cells, remodelling of the extracellular matrix. This is why cancer has been likened to a wound that never heals, the tumour stroma being chronically activated and promoting growth and angiogenesis (Dvorak, 1984).
The rapid proliferation of tumour cells soon exhausts the existing vascular supply and brings about a hypoxic environment in the TME (Coussens and Werb, 2005). Endothelial and stromal cells form a
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