Introduction
Inherited disorders or birth deficiencies and other common illnesses like cancer are entails alteration in the DNA i.e. genetic structure of deoxyribonucleic acid. Through principles of inheritance, the cell cycle and also the environmental influences, we are able to understand the crucial process of this disease. Cancer is a disease that is typified by uncontrollable cell growth. There are over hundred dissimilar kinds of cancer and every type is classified by the kind of cell that is originally affected. Cancer damages the body when the harmed cells separate unmanageably to form chunks of tissue known as tumors however in leukemia cancer prevents normal blood functioning by anomalous cell-division in the blood flow. These tumors can multiply and meddle with digestive systems, nervous systems and also the circulatory systems; these tumors can bring about hormones thus changing the normal functioning of the body.
Literature Review
Aberrant Chromosomal Numbers
Inherited disorders to birth sicknesses are very common today than people realize. Many impulsive abortions are as a result of chromosomal defects, even if it is the number or the construction of chromosomes. Down syndrome or trisomy of chromosome 21(3 copies rather than two) is a chromosomal disorder that results in psychological retardation and physical aberration; this is the most widespread chromosomal disorder that takes place during meiosis (Porth, 2007).
Aberrant Chromosomal Structure
Throughout the meiosis process, chromosomes mostly swap DNA blocks or the alleles thus causing deviation in the chromosomes. In cases where this swap or exchange is not accurate, the deviations can be lethal to the gamete. This swap can also take place during mitosis leading to the death of the cell or continuation of mutation in the cell line (Dakubo, 2010). This genetic material’s translocation is drawn in as the reason behind many cancers. One case is Philadelphia chromosome where DNA translocation consisting of chromosome 9 and 22 brings about CML i.e. Chronic myeloid leukemia.
The translocation brings about novel protein-tyrosine kinase that endorses unregulated development of myeloid cells. Medication that is used to treat chronic myeloid leukemia, Gleevec and Novartis particularly obstructs the tyrosine kinase thus slowing the development of the myeloid cells (McCance & Heuther, 2006). Neuroblastoma a cancerous tumor is linked with MYCN gene duplication. This gene is an oncogene, this means that in its non-mutated state, it both directs and controls the propagation of particular cells. In the mutated state, propagation is uncontrolled and as a result it brings about tumors.
Single Gene Mutations
During the processes of mitosis and meiosis, the chromosomes are exactly and accurately copied. If one or more of the bottom pairs in the DNA cycle of a gene is distorted there is a likelihood of a point mutation in this gene. This single malfunctioning gene one a chromosome can bring about grave alterations in the body functioning like Marfan syndrome. This is an autosomal dominant disease that has fifty percent possibility of being spread to progeny. The BRCA1 and BRCA2 genes are autosomal dominant and are associated with the cancer of breast.
BRCA1 can be located on chromosome 17 whereas the BRCA2 can be found in chromosome 13 (Chung, 2010). HER2/neu or Human Epidermal growth factor Receptor 2 gives cancer of breast soaring aggressiveness. This gene brings about unnecessary growth signs to the nucleus. Herceptin (trastuzumab) is a treatment used on women with HER2/neu because it obstructs the receptors for developmental factor. Ras gene mutations thwart the GTP breakdown, this then permits the cytoplasmic signaling molecules to stay active and kindle cell growth improperly. Cancer of blood, lung, colon and ovarian are all connected to the Ras gene (Copstead & Banasik, 2005).
Environmental and Lifestyle Risk Factors
Environmental Risk Factors
With billions and billions of cells replicating, it is amazing that the process does not incur more errors. Environmental influences increase the risk of errors in replication. Known chemical carcinogens include benzopyrene, which is found in foods fried in fat. Nitrosamines found in smoked, salted, and cured foods are also powerful carcinogens. The tars and nicotines in cigarettes are also cancer promoters. In addition, the ultraviolet rays of the sun can cause mutation of the p53 gene, thereby causing squamous cell carcinoma and a mutation in the p16 gene related to melanoma. The UV light also activates tumor necrosis factor-a (TNF-a), which seems to reduce the immune surveillance system (McCance & Heuther, 2006).
Lifestyle Risk Factors
Obesity has been linked to increasing the risk of cancer. The adipose tissue produces enzymes that increase the levels of free estradiol and testosterone. The receptors react to the increased levels by causing cellular proliferation and inhibiting apoptosis (McCance & Huether, 2006), increasing the risk of tumor development. Viruses such as human papillomavirus (HPV), hepatitis B virus, and the Epstein – Barr virus have been associated with cancer. The DNA of HPV becomes incorporated into the nucleus of cervical cells and directs the proliferation of the virus.
Cell Cycle
Now that the chromosomal and gene mutations have been discussed, the process of cell division and growth as it relates to cancer needs to be understood. Cells that replicate have a five-phase cell cycle. During the S phase of the cell cycle, chromosomes are replicated. It is during this phase that environmental factors can affect the exact replication and cause mutations. The end of the G2 phase allows for a quality control check of the replication. Alterations of the kinases that control this checkpoint allow mutations to continue rather than be corrected, increasing the chances of cancer.
Tumor Cell Transformation
Promotion Stage
Once a cell has survived one gene alteration, it must be able to continue to replicate and survive. Promotion is the stage in which the altered cells proliferate. In the progression stage, cancer cells often lose their ability to function and are not like the original tissue cells. These cells are considered anaplastic. Contact inhibition is lost and the cancer cells overwhelm the area in which they began. These malignant cells secrete proteases that destroy healthy cells and allow space for the cancerous cells to grow.
Cancer Cell Growth
Continued growth of the cancer cells depends on an enough blood supply. Tumor cells can secrete vascular endothelial growth factor (VEGF) along with other growth factors that promote angiogenesis. As the blood supply increases to the tumor, the metastatic potential increases. Research is directed toward developing agents that can block the enzymes that support angiogenesis. Without a good blood supply, cancer cells die.
Cancer Expansion
Cells of cancer do not adhere to each other as do the cells in normal tissue. Given a good blood supply or a lymphatic channel, the cancer cells can break away from the primary site and metastasize to other areas in the body. It may take years for the cancer cells to overcome the normal cells in the new site, so they can go undetected.
Cancer Signs and Symptoms
Early Stages
In the early stages of cancer, there are typically not perceptible symptoms. Exhaustion like ache is very subjective and the reason for the fatigue is being researched. Pain is due to inflammation, stretching of visceral surfaces, firmness of nerve endings, and bone metastasis. In addition, pain control is an ongoing problem in treating patients with cancer.
Later Stages
Cachexia or severe malnutrition is found in the later stages of cancer and is often the cause of death. TNF-a produced by macrophages has been implicated as a cause for the depression of protein synthesis and the boost of degradation of protein. Anemia is also a common finding, as are leucopenia and thrombocytopenia due to suppression of the bone marrow.
Cancer Therapy Research
Throughout the lecture, different treatment therapies have been mentioned. Surgical procedure, chemotherapy, and radiation continue as mainstay treatments. Immunomodulation therapy uses interferons, interleukins, monoclonal antibodies, and hematopoietic development factors to destroy cancer cells. The interferons inhibit cancer cell proliferation and stimulate NK cells, T cells, and macrophages. Interleukin 2 stimulates the proliferation of T cells, NK cells, and macrophages, increasing the number available to destroy cancer cells.
Monoclonal antibodies are specific to certain tumor cell receptors blocking growth factors as well as identifying the cell to the NK cells as foreign. The hematopoietic growth factors are used to stimulate production of neutrophils, macrophages, erythrocytes, and platelets in order to support the tissues during the tumor destruction.
Research into gene therapy involves attempting to alter the genetic structure of the tumor cells, making them more susceptible to the immune system, or replacing the missing p53 gene by transporting it into the tumor cell using an inactivated virus. Stem cell transplant involves harvesting stem cells from the bone marrow of a closely matched donor and transplanting the stem cells. The therapy serves to restore the function of the once cancerous bone marrow. In addition, research is being done on vaccines for specific cancers. The HPV vaccination, Gardisil, is a beginning, whereas another area of research is being studied to inhibit the protelytic enzymes that allow the cancer cells to expand and metastasize.
Physiological/psychological side effects of care
Several cancer victims and survivors can possibly experience some degree of sexual dysfunction. This may happen to both men and women. The cancer victims also many experience regular and constant pain after lengthened cancer treatment. Both men and women survivors of cancer may experience sterility/barrenness. These patients may feel always tired without the drive or the vigor to finish simple daily tasks. Depression and stress is mostly experienced by these patients, this is because of the devastating cancer treatment. It is very imperative for cancer survivors to have well-built friendship networks to assist them get over their problems that rises after going through chemotherapies.
Conclusion
Understanding genetics is important for the clinician who works with families who are or wish to become pregnant in order to explain the risks of birth defects and other genetically linked diseases. Every nurse needs to be able to educate patients on the environmental and lifestyle risks associated with cancer along with the genetic link. For those patients who are already being treated for cancer, the nurse should be able to explain how the medications and radiation help treat the disease.
References
Copstead, L. E., & Banasik, J. (2005). Pathophysiology (3rd ed.). St. Louis, MO: Elsevier Saunders.
McCance, K. L., & Huether, S. E. (2006). Pathophysiology: The biological basis for disease in adults and children (5th ed.). St. Louis, MO: Elsevier Mosby.
Porth, C. M. (2007). Essentials of pathophysiology: Concepts of altered health states (2nd ed.). Philadelphia: Lippincott Williams & Wilkins.
Dakubo G. D. (2010). Mitochondrial Genetics and Cancer. New York. Springer
Chung D.C. (2010). Principles of Clinical Cancer Genetics: A Handbook from the Massachusetts General Hospital. Chicago. Springer
