Genetic nature of cancer can be analysed from two perspectives: cancer genetics and cancer genomics. Genetic inclination to cancer is stipulated by some inherited genetic defects. Tumor progression is also genetically determined by the accumulation of distinct genetic changes in cells. Such changes are the cause of the tumorigenic properties of cancer cells. The accumulation of genetic abnormalities, which in most cases occurs over a period of years, underlies both the process of tumorigenesis and tumor progression. Most kinds of cancers in humans comprise a vast amount of genetic disorders. Identification of cancer driving disorders has important implications for the new generation of cancer therapies. In clinical cancer care, it is important to understand methods used to diagnose and treat a disease. This study analyzes cancer genetics, its development and treatment.
To understand the role of gens in the etiology of cancer, some basic concepts of human genetics should be observed. It is a well-known fact that DNA that is the main source of genetic information is inherited by a child from his or her parents. DNA comprises of 22 pairs of autosomal chromosomes and chromosomes X and Y that are responsible for sex identification. Each parent donates one copy to every pair. The gen is the main unit of genetic information. Every individual inherits one copy of gene from parents to form his or her own genotype. Disposition to cancer depends on one’s genotype and the penetration of gene.
Schneider assumed that many factors may affect the penetration of a certain gene. As thus, many factors influence the development of different types of cancer. It is estimated that all affected individuals usually have at least one affected parent. Autosomal dominant transmission is the most frequent type of genetic cancer. For example, 50% of the children of the parents with hereditary retinoblastoma eventually develop this rare malignancy. According to the research, 50% percent of children inherit the defective gene from their parents, and 90% percent of them will obtain this type of cancer later in their life.
The disease is a result of the process of mutation of the normal gene. With age mutation increases and leads to hereditary cancer. Genetically susceptible individuals, though normal at birth, are more often subject to different types of cancer. No one knows the real reasons of cancer, but individuals who have genetic adherence should be especially careful and take all protective measures to prevent the disease.
Hereditary Cancer Risk Assessment
Cancer genetics is a rapidly evolving field, which has revolutionized medicine. Scientists have investigated this field and achieved some important results. Thus, genetic testing helps identify individuals at high risk for breast and colon cancers that can be effectively prevented with early screening. Chung & Haber argue that somatically acquired genetic changes such as overexpression of ERBB2 gene in breast cancer and mutations of the KRAS or BRAF genes in colorectal cancer are observed in a significant number of patients. These genetic abnormalities can be effectively treated with antibodies such as trastuzumab and cetuximab. Early treatment of these genetically targeted agents increases patient survival.
Bunz confirmed that while genetic information relates to medical sphere, its uses and abuses may reach beyond the patient to the family and society. For these and other reasons, predictive genetic information was introduced into the practice of clinical oncology as a special case requiring attention. At the time of the first introduction of genetic testing for breast, colon, and ovarian cancer, many experts considered “genetic exceptionalism” as the one that should be introduced because of the exceptional social, psychological and economic consequences of genetic information. Nowadays, most professionals deny the theory of genetic exceptionalism. Moreover, many of them assume that there are more similarities than differences between genetic and non-genetic predictive testing.
Clinical Features of Hereditary Cancer
Many studies have proved that patients who have family cancer history are in the risk category. As a rule, people at risk possess rather early syndromes of different types of cancer. However, the risk increases with age. Schneider reported that genetic cancer occurs in individuals regardless of their race, sex and socioeconomic status. Thus, breast cancer can be inherited from mother to daughter and granddaughters in different geographical locations. The same type of cancer usually clusters in close relatives. Moreover, cancer may occur in many generations of relatives. It is imperative that health care providers become more familiar with the tools to assess a person’s genetic risk of cancer and the process of making decisions about diagnosis and treatment of malignant disorders.
Potential genetic problems may affect family members with different types of cancers such as breast, colorectal, ovarian, endometrial, and prostate cancer. If a mother, for example, had a breast cancer, her daughter would be at double risk. The research asserts that inherited factors play a predominant role in developing cancer. Maternal or paternal lineage may affect their children’s genes and lead to mutation that is the main reason of cancer. Mutant genes extremely influence the high risk of cancer. However, they are less often in the general population than genetically inherited. Fortunately, sustainable progress has been made over the last decades in the identification of the genes that are responsible for major hereditary cancer syndromes. Many of these genes have been cloned or mapped to specific locations within the human genome.
Epidemiological Approaches to Genetic Cancer
Various approaches to studying genetic cancer should be applied in modern medicine. The researchers attempt to investigate genetic factors and their potential interaction with the environmental exposures. The most common studies that identify etiology of genetic cancer are family studies, segregation studies and genetic biomarker studies. Health care professionals use family studies to analyze families’ histories of cancer. Both case-control and cohort studies help to investigate the interaction between familial cancer history and cancer risk. Bunz reported that although epidemiological studies of familial cancer history are the basis for genetic epidemiology, data from these studies is rather difficult to interpret. For instance, certain life style factors and eating habits could be associated with the development of cancer.
Segregation analysis of cancer is practically an extension of the traditional epidemiological approach to family history. Segregation analysis is provided with the aim to determine the way in which the disease was inherited. Family data collected from cancer patients are analyzed to identify the most likely disease transmission pattern in families. The specific patterns of transmission within families vary according to whether the genes are dominant or recessive, X-linked or autosomal, multifactorial or polygenic. The aim of the investigation is to identify the model which best explains the data. However, there are some factors that affect data, such as environmental factors.
Genetic biomarker studies attempt to discover the correlation between specific genetic markers and risk factors. Moreover, they provide direct evidence for the involvement of genetic factors in the etiology of cancer. The most commonly used approach in studying genetic cancer is traditional case-control study. Chung and Haber argued that in order to investigate measures in epidemiological approaches to genetic cancer, investigators used to collect family-based control and apply transmission disequilibrium test statistics.
Genetic Epidemiology of Cancer
The aim of genetic epidemiology is to identify inherited susceptibility factors for prevention of diseases. Cumulative evidence indicates that genetic factors contribute to the development of most cancer cases, including those without a clear familial aggregation. Most hereditary cancer syndromes are caused by the mutation or deletion of a single gene. The critical functions of cells lead to abnormalities of gene. Mutation of genes predetermines the risk of cancer. The majority of the hereditary cancer syndromes include different types of cancers that can affect multiple generations in the future.
The research asserts that ordinary detection of genes is rare in the general population. However, it may occur in the individuals who belong to the genetic risk group. In some cases, coupled with environmental risk factors polymorphic genes may affect the general population as well. Various epidemiological study designs can be used to investigate genetic factors for cancer. The choice of the particular study depends on the frequency of the disease, the frequency of the genetic factors as well as the mechanism of genetic influence on the disease. In the last decades, a substantial progress has occurred in the field of genetic epidemiology of cancer.
Due to the advances in DNA recombinant technology and related techniques in molecular epidemiological studies, much of the progress has been done in the last decades. These techniques in most cases are reliable and efficient. The research asserts that because of the current rate of progress in molecular biology, the human understanding of the genetic basis of cancer will continue to develop finding new methods of prevention and treatment.
Diagnosing and Treatment of Genetic Cancer
Diagnosing and treatment of genetic cancer are rather challenging and complicated. Health care professionals use modern technology to diagnose and treat cancer. According to new research, different types of cancer, breast cancer in particular, could change the way it is diagnosed and treated. Some findings in modern medicine prove that leading technologies and new methods of treatment may decrease side effects. The genomic approach in treatment can review all previous methods that did not prove their validity. The genomic approach can eliminate errors in treatment. Most professionals consider diagnosis that should be provided in the early stages of cancer as the cornerstone of treatment.
Another important aspect is that in recent years clinical laboratory science has been developed by generic molecular genetic technologies. These achievements have enforced patients’ hopes for successful treatment of cancer. Many laboratories that offer diagnostic molecular genetic testing on a routine basis are originated from research-based settings. It is important to increase the number of the laboratories that attempt to reorganize and standardize their methods and procedures. Laboratories need to ensure that all processes are well controlled in terms of quality and use of reference materials.
Schneider assumed that with current approaches and understanding how genetic and genomic factors contribute to the development of genetic cancer, it has become possible to implement new approaches in prevention, diagnosis, treatment and surveillance of the disease. Nowadays, a set of molecular analyses is well implemented in laboratories and covers different aspects. Moreover, recent advances in pharmacogenetics and pharmacogenomics have gradually improved the genetic basis of individual differences in drug responses. New technology and innovative methods of treatment steadily replace old methods of treatment such as chemotherapy.
The analysis of the nature of genetic cancer makes it possible to notice that most types of human cancers comprise a vast amount of genetic disorders. Modern approaches used to study, analyze, prevent and treat cancer give an opportunity to fight this disease in the future. Much of the progress is done due to the advances in DNA recombinant technology and related techniques in molecular epidemiological studies. Cancer genetics is a rapidly evolving field, which has revolutionized the practice of medicine application. Researchers have investigated this field and achieved some important results. Contemporary achievements in diagnosing and treatment ensure patients’ survival in the fight with this dreadful disease. Therefore, the humanity has a chance to prevent and treat genetic cancer more efficiently.