Cancer is a disease characterized by uncontrolled division of body cells. The uncontrolled division of body cells is caused by genetic mutations in the genes coding for proteins that regulate cell growth and apoptosis. Cancerous cells have some unique characteristics like increased rate of cell division, avoidance of cell death, and initiation of angiogenesis. Cancer cells also exhibit altered differentiation, nonresponsiveness to antigrowth factors and contact inhibition and self-sufficiency in growth factors (Connie et al, 2011, pg 39).
Cancerous cells are highly invasive. The ability of the cancerous cells to spread to other regions of the body is called metastasis. The transfer of malignant cells through the lymphatic and circulatory systems enhances metastasis. Connie et al, (2012, pg 44), states that metastasis occurs in a five step process that includes,
1) The penetration and the invasion of normal body tissue neighboring malignant cells through blood and lymph channels
2) The injection of single or lumps of cells into the body circulation
3) The continued survival of neoplastic cells in the body circulation
4) The holding of neoplastic cells in the capillary beds of body organs
5) The penetration of cancerous cells into the lymph and blood vessels and tumor growth
Cancer cells are classified according to their cell of origination. For example, carcinoma refers to cancer from the epithelial cell and Glioma for cancer originating from the brain cells.
Mutations in proto-oncogenes are associated with cancer. Proto-oncogenes are genes that have the ability of changing to oncogenes. Oncogenes are dominant genes that produce excessive amounts of growth promotion proteins causing uncontrolled cell division. Mutations in the recessive tumor repressor genes that produce tumor-inhibiting factors like p53 also result in cancer. Mutations in proto-oncogenes and tumor repression genes are the ones responsible for causing cancer (Connie et al, 2011, pg 47).
Connie Henke et al (2010) Cancer nursing principles and practice. London: John Bartlett
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