This article needs attention from an expert in Medicine. The specific problem is: Needs to be based on secondary sources (think review articles) not primary sources.(May 2013) |
Lung cancer susceptibility tests suggest the probability or susceptibility an individual may have of getting lung cancer. Lung cancer is a disease characterized by uncontrolled cell growth in the lung tissue. If left untreated, this growth can spread beyond the lungs in a process called metastasis, into nearby tissues or other parts of the body.
Lung cancer is one of the most lethal and common forms of cancer worldwide. Pollution, smoking (active and passive), radiation (in the form of x-rays or gamma rays) [1] and asbestos are risk factors for lung cancer. Symptoms may include persistent cough, chest pain, coughing up blood, fatigue, and swelling of the neck and face. There are different types of lung cancers, which can metastasize. Treatments include chemotherapy, surgery, and radiation. [2] The treatment aimed at killing the cancer can also eliminate functioning lung cells (leukocytes). Specific genetic factors can add to the risk of developing lung cancer. There are regions on chromosomes which are highly susceptible to mutation and, if present, increase the risk of developing lung cancer. These loci are the specific locations of a gene or a DNA sequence on a chromosome. Several loci are associated with an increased risk of developing lung cancer. [2] Approximately 26 different genes can mutate into one type of lung cancer, known as carcinoma. An example is the MAP pathway, which is inhibited by ME (a lung cancer treatment). The risk of developing lung cancer is higher for those with a family history of the disease. A second way the risk could go up is if the individual lives with a smoker.
Many chromosomes are involved in the development of lung cancer, but those that greatly increase one's susceptibility to developing lung cancer are loci 15q25, 5p15, and 6p21. The locus 5p15 spans about 181 million base pairs on the short arm of chromosome 5, which is the largest chromosome. The locus 15q25 on chromosome 15 has genetic variants such as the CHRNA5-CHRNA3 locus, which also increases lung cancer susceptibility. Smoke is one of these risk factors: rs12914385, and rs8042374 are treated in cases where smoking is the known cause of lung cancer. [3] [4]
Abnormal gene expression in chromosome loci, such as 5p15 and 15q25, is strongly linked with the risk for developing lung cancer. Gene expression, or the "turning on" of the gene, can directly affect the chromosome by changing the coding system. The process of lung cancer development transforms healthy cells into cancer cells, which can then metastasize to different parts of the body. [3]
In a large number of cases, the locus in chromosome region 15q25, which is strongly associated with lung cancer risk, was found to account for 14% (attributable risk) of lung cancer cases. Statistically similar risks were observed irrespective of smoking status or of one's propensity for smoking tobacco. The associated region contains several genes, including three that encode nicotinic acetylcholine receptor subunits (CHRNA5, CHRNA3, and CHRNB4). Such subunits are expressed in neurons and other tissues, in particular alveolar epithelial cells, pulmonary endocrine cells, and lung cancer cell lines, and they bind to N'-nitroglycerine and potential lung carcinogens. A non-synonymous variant of CHRNA5, which induces an amino acid substitution (D398N) at a highly conserved site in the second intracellular loop of the protein, is among the markers with the strongest disease associations. [5] [6]
Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged airway cells gain the ability to multiply unchecked, causing the growth of a tumor. Without treatment, tumors spread throughout the lung, damaging lung function. Eventually lung tumors metastasize, spreading to other parts of the body.
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans.
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, are metastases (mets). It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues.
A sarcoma is a malignant tumor, a type of cancer that arises from cells of mesenchymal origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or other structural tissues, and sarcomas can arise in any of these types of tissues. As a result, there are many subtypes of sarcoma, which are classified based on the specific tissue and type of cell from which the tumor originates. Sarcomas are primary connective tissue tumors, meaning that they arise in connective tissues. This is in contrast to secondary connective tissue tumors, which occur when a cancer from elsewhere in the body spreads to the connective tissue. Sarcomas are one of five different types of cancer, classified by the cell type from which they originate. The word sarcoma is derived from the Greek σάρκωμα sarkōma 'fleshy excrescence or substance', itself from σάρξsarx meaning 'flesh'.
Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs. The area most commonly affected is the lining of the lungs and chest wall. Less commonly the lining of the abdomen and rarely the sac surrounding the heart, or the sac surrounding the testis may be affected. Signs and symptoms of mesothelioma may include shortness of breath due to fluid around the lung, a swollen abdomen, chest wall pain, cough, feeling tired, and weight loss. These symptoms typically come on slowly.
Malignancy is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer.
Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Such a gene that exhibits multiple phenotypic expression is called a pleiotropic gene. Mutation in a pleiotropic gene may have an effect on several traits simultaneously, due to the gene coding for a product used by a myriad of cells or different targets that have the same signaling function.
Chromosome 6 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 6 spans more than 172 million base pairs and represents between 5.5 and 6% of the total DNA in cells. It contains the major histocompatibility complex, which contains over 100 genes related to the immune response, and plays a vital role in organ transplantation.
Non-small-cell lung cancer (NSCLC), or non-small-cell lung carcinoma, is any type of epithelial lung cancer other than small-cell lung cancer (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to small-cell carcinoma. When possible, they are primarily treated by surgical resection with curative intent, although chemotherapy has been used increasingly both preoperatively and postoperatively.
Ewing sarcoma is a type of pediatric cancer that forms in bone or soft tissue. Symptoms may include swelling and pain at the site of the tumor, fever, and a bone fracture. The most common areas where it begins are the legs, pelvis, and chest wall. In about 25% of cases, the cancer has already spread to other parts of the body at the time of diagnosis. Complications may include a pleural effusion or paraplegia.
Neuronal acetylcholine receptor subunit alpha-5, also known as nAChRα5, is a protein that in humans is encoded by the CHRNA5 gene. The protein encoded by this gene is a subunit of certain nicotinic acetylcholine receptors (nAchR).
The Interleukin-2 receptor alpha chain is a protein involved in the assembly of the high-affinity Interleukin-2 receptor, consisting of alpha (IL2RA), beta (IL2RB) and the common gamma chain (IL2RG). As the name indicates, this receptor interacts with Interleukin-2, a pleiotropic cytokine which plays an important role in immune homeostasis.
TOX high mobility group box family member 3, also known as TOX3, is a human gene.
Mark Lathrop is a Canadian Biostatistician. He headed the Center for the Study of Human Polymorphisms, but returned to Canada as Scientific Director at McGill University and Genome Quebec's Innovation Centre in 2011.
Cleft lip and palate transmembrane protein 1-like protein, also known as cisplatin resistance-related protein 9 (CRR9p), is a protein that in humans is encoded by the CLPTM1L gene. CRR9p is associated with cisplatin-induced apoptosis. CLPTM1L, which lies within a cancer susceptibility locus on chromosome 5 (5p15.33), has been found to be commonly over-expressed in lung tumors and to confer resistance to apoptosis caused by genotoxic agents in association with up-regulation of the anti-apoptotic protein, Bcl-xL. Inhibition of CLPTM1L has been shown to inhibit oncogenic transformation and tumorigenesis caused by the KRas oncogene partially through the PI3K/Akt survival signaling axis.
A gene is said to be polymorphic if more than one allele occupies that gene's locus within a population. In addition to having more than one allele at a specific locus, each allele must also occur in the population at a rate of at least 1% to generally be considered polymorphic.
Cancer is caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic (non-familial) cancers is DNA damage and genomic instability. A minority of cancers are due to inherited genetic mutations. Most cancers are related to environmental, lifestyle, or behavioral exposures. Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer bacteria. The term "environmental", as used by cancer researchers, refers to everything outside the body that interacts with humans. The environment is not limited to the biophysical environment, but also includes lifestyle and behavioral factors.
Phosphatase and actin regulator 1 (PHACTR1) is a protein that in humans is encoded by the PHACTR1 gene on chromosome 6. It is most significantly expressed in the globus pallidus of the brain. PHACTR1 is an actin and protein phosphatase 1 (PP1) binding protein that binds actin and regulates the reorganization of the actin cytoskeleton. This protein has been associated with coronary artery disease and migraines through genome-wide association studies. The PHACTR1 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.
Joan Ellen Bailey-Wilson is an American statistical geneticist. She is a senior investigator and co-chief of the Computational and Statistical Genomic Branch of the National Human Genome Research Institute.
N-Acetylated Alpha-Linked Acidic Dipeptidase Like 2 (NAALADL2) is a protein, encoded by the gene NAALADL2 in humans. NAALADL2 shares 25%–26% sequence identity and 45% sequence similarity with the glutamate carboxypeptidase II family which includes prostate cancer marker PSMA (FOLH1/NAALAD1). The NAALADL2 gene is a giant gene spanning 1.37 Mb which is approximately 49 times larger than the average gene size of 28 kb. Gene length is correlated with the number of transcript variants of a gene, as such, NAALADL2 undergoes extensive alternative splicing and has 12 splice variants as defined by Ensembl.
{{cite journal}}
: Check |url=
value (help)