Cancer

• The most common cancers are lung, breast, prostate, colorectal, melanoma, bladder, kidney, pancreatic, ovarian, thyroid, leukaemia, stomach, liver, brain and bone marrow.
• Cancer

  group of diseases caused by damage to the genes that regulate mitosis and the cell cycle which leads to unrestrained growth of cells
• Tumour

  group of abnormal cells
• Malignant tumours


  -cancerous

  -grow rapidly

  -cell nucleus is often larger and appears darker due to abundance of DNA

  -cells have become de-differentiated (unspecialised and so you cannot tell where they come from)
• Malignant tumours 


  -Tumours are not surrounded by a capsule and can grow finger like projections into surrounding tissues

  -cells do not produce adhesion molecules, cells can break off these tumours and spread to other parts of the body through the blood stream and lymphatic system- this produces secondary tumours (METASTASIS)
• METASTASIS


  cells break off these tumours and spread to other pars of the body through the bloodstream or lymphatic system forming secondary tumours
• malignant tumours 


  -can secrete chemicals that cause the formation of blood vessels to supply the tumour with nutrients, growth factors and oxygen

  -systematic effect such as weight loss and fatigue

  -abnormal tissues replace normal tissues

  -radiotherapy, chemotherapy, immunotherapy and surgery
• Angiogenesis


  diverts blood to tumours
• Tumour cells differs to normal cells

  -irregular shape

  -different antigens on surface

  -divide by mitosis more frequently
• Epigenetic


  heritable changes in gene functions without changes to the bases sequence of DNA
• methylation of DNA


  methyl groups attach to tumour suppressor genes

  this causes a mutation in the tumour suppressor gene

  transcription of tumour suppressor gene is inhibited

  regulation of transcription cannot occur (protein that prevents cell division is not produced)

  no control of mitosis= uncontrolled cell division