Exploring the Biology of Breast Cancer - Essay Example

The Biology of Breast Cancer Background Body cells divide constantly so as to replenish dead cells and assist in the repair of worn out body tissues such as the lining of the alimentary canal. Cancer may be termed as the uncontrolled proliferation of cells. The cancerous cell may not undergo apoptosis and may keep growing and invading other tissues. The spreading of the tumor from the initial primary lesion to other tissues is referred to as metastasis. Tumors in cancers may be benign or malignant. Benign tumors are not life-threatening since they do not metastasize as in the case of malignant tumors. Incidences of cancer increases with age as DNA repair mechanism and repair mechanism fail. Cancers, including breast cancer, may result from events that allow the inappropriate expression or the activation of genes. In other events the growth of tumors may be as a result of inactivation of genes or gene products. Genes which are activated by mutation are called oncogenes and these genes may be involved in signaling pathways that stimulate proliferations whereas the tumor suppressor genes are those that are inactivated by mutations. Usually suppressor genes are genes which may encode proteins in the check point pathways such as those involved in the programmed cell death (apoptosis). Breast Cancer Breast cancer is a major public health concern especially among women worldwide. Among women, breast is the most prevalent form of cancer and it is ranked second from lung cancer as a leading cause of cancer-related mortality (Harris et al 319). Majority of deaths associated with breast cancer are due to metastasis. This is the spreading of the tumor from its primary location in the breast tissue to other body tissues. As a form of cancer, breast cancer may adopt any of the following pathways in the genesis of the cancerous cell. The cell may overcome the cellular senescence and adopt an infinite proliferative profile or develop refractoriness to apoptosis or even inhibitory signals. In some cases, the initiation of cancerous cell may be due to a development of independence in the growth stimulatory signals. The breast is made up of lobules which are glands that produce milk, ducts which deliver milk to the nipples in addition to fatty and connective tissues, blood vessels and lymph vessels. Most forms of breast cancer are initiated at the lobules or ducts lining. Figure 1: Illustration of the human breast showing the lobules and ducts (adapted American Cancer society (n.d) Pathology of breast cancers: causes and predisposing risks Breast cancers may be divided according to their pathophysiology with in situ carcinomas arising from and becoming confined in the ductal or lobular epithelium. Due to the confinement in this form of breast cancer cases of metastasis are minimized. In infiltrating ductal or lobular carcinoma, the carcinoma extends beyond the basement membrane of the epithelial border. Although breast cancer affects men, majority of the victims are women with the American Cancer Society (6) estimating that over 200,000 new cases of invasive cancer and a further 63, 300 new cases of in situ carcinoma affecting women in the United States in 2012 alone. Possible etiology of breast cancer is not fully established but factors associated with environment, physiology and hormones and genetics factors may contribute to the disease. The major possible cause of breast cancer may be due to mutations in certain genes. Common mutations may include germline mutations in two genes, BRCA1 and BRCA2 in chromosome 17q and 13q respectively has been reported as possible links to female breast cancer (Eston and Peto 395). Mutations in these genes predispose an individual to risks of having breast cancer. Other genes that have been mentioned as possible causes of cancer may include the ataxia telangiectasia (ATM gene) which is associated with rare cases of autosomally inherited cancers. Incidences of breast neoplasm may be lowered due to early pregnancy or oophorectomy if diagnosed early. However late menopause has been associated with a high incidence of breast cancer (World Health Organization 15). Oral contraceptives have also been mentioned as possible predisposing factors in addition to hormone use in menopause (Collaborative Group on Hormonal Factors in Breast Cancer 1714). Environmental factors which may have been reported as a possible risk to breast cancer may include ionizing radiations usually in medical diagnostic or therapeutic procedures (International Agency for Research on Cancer 12). Nutritional conditions such as obesity are a potential risk to increased breast cancer especially in postmenopausal women. In inflammatory breast cancer, there is a rapid progression and aggressive onset of breast cancer. This form of cancer is rare. Albeit the cancer is termed inflammatory, it is not associated with bacterial infections such as mastitis that often present symptoms such as fever and localized pain. Diagnosis of the disease is on the basis of historic evidence in addition to observation of histopathological findings in mammary parenchyma and the overlying skin. Symptoms Symptoms of breast cancer include inflammatory lesions which maybe acute or chronic and mastitis. Benign fibrocystic lesions are also common in breast cancer. These lesions are a result of hormonal imbalances and may rarely develop after postmenopause. In breast cancer, benign breast disease such as fibro adenomas, large duct papilloma and phyllodes tumors may also occur. Diagnosis and treatment Diagnosis of cancer is an important process that is critical in the management of breast neoplasm since it may guarantee better management. Morbidity and mortality due to this form of cancer may be drastically minimized as a result of early diagnosis for breast cancer. Forms of diagnosis may range from self-examination albeit it is dependent on education and outreach especially to the target population, women. Clinical breast examination is also a primary mode of breast cancer diagnosis that also depends on the skill of the medical worker. Mammography as a breast cancer diagnosis tool will depend on the equipment used and the radiologist reading the mammogram. The technique is X-ray based and it is employed for breast lesion examination. Different tissues of the breast will have different absorption of X-rays; these tissues may include fibroglandular tissue, cysts, fat, tumors and calcifications. Other forms of breast cancer screening methods include magnetic resonance imaging (MRI), computed tomogragraphy (CT), ultrasonography, nuclear medicine breast imaging, positron emission tomographic screening (PET) and guided breast biopsy. Successful treatment of breast cancer will depend on early screening of breast cancer. Surgery may also be a remedy in treatment in addition to chemotherapy and radiation procedures. Palliative care and support is essential in making the breast cancer patient come to terms with her conditions and thereby improve the quality of life. In the United States, over 5% of breast cancer patients present with metastatic breast cancer (Jain and Cigler 21). Treatment of metastatic breast cancer is a complex process which attempts to balance between successful treatments with minimal toxicity to the patients. Chemotherapy agents recommended for metastatic breast cancer include capecitabine, ixabepilon and eribulin mesylate. These chemotherapeutic agents are geared towards inhibiting cancerous cell proliferation. For instance, eribulin binds tubulin and destabilizes microtubule dynamics. This leads to sequestration of tubulin to non-functional aggregates thereby causing an irreversible arrest of mitosis at G2-M phase (Jordon et al 1087). Conclusion Early screening is important in guaranteeing proper management of breast cancer, however it should be noted that early screening will just detect lethal cancers earlier or in other cases cancers that are progressing slowly will be diagnosed. Various arguments have persisted in the understanding of breast cancer as whether it can be classified as a systematic disease. This stems from the fact that metastases may be averted through early screening of the cancer. In other cases Harris et al (324) argues that metastasis may occur earlier in breast cancer thereby ruling out its classification as a systemic disease. Although chemotherapy and radiation continues to serve as the primary preventive and treatment modes for breast cancer, it imperative for extra studies to establish novel treatment methods for the patient with the overall objectives of minimizing toxicity in treatment while improving the quality of life in these patients. Work Cited American Cancer Society (n.d). “Breast Cancer Overview” http://www.cancer.org/acs/groups/cid/documents/webcontent/003037-pdf.pdf. Collaborative Group on Hormonal Factors in Breast Cancer. “Breast Cancer and Hormone Replacement Therapy.” Lancet, 1997, 350:1047–1059. Eston, D. and Peto, J. “The Contribution of Inherited Predisposition to Cancer Incidence.” Cancer Surv. 1990: 9(3): 395-416. Harris, J., Lippman, M., Veronesi, U. and Willett, W. “Breast Cancer.” N. Engl. JMed.1992:327:319-479. International Agency for Research on Cancer. “Monographs on the evaluation of carcinogenic risks to humans.” Vol 75. Ionizing radiation, Part 1.Lyon, International Agency for Research on Cancer Press, 2000. Jain, S. and Cigler, T. “Eribulin Mesylate in the Treatment of Metastatic Breast Cancer” Biologics. 2012; 6: 21-29. Jordan, M.A., Kamath, K., and Manna, T. “The Primary Antimitotic Mechanism of Action of the Synthetic Halichondrin E7389 is Suppression of Microtubule Growth.” Mol Cancer Ther. 2005; 4:1086-1095. Read More