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50-443: A growth factor is a naturally occurring substance capable of stimulating cell proliferation , wound healing , and occasionally cellular differentiation . Usually it is a secreted protein or a steroid hormone . Growth factors are important for regulating a variety of cellular processes. Growth factors typically act as signaling molecules between cells. Examples are cytokines and hormones that bind to specific receptors on

100-490: A " great imitator ". People may become anxious or depressed post-diagnosis. The risk of suicide in people with cancer is approximately double. Local symptoms may occur due to the mass of the tumor or its ulceration. For example, mass effects from lung cancer can block the bronchus resulting in cough or pneumonia ; esophageal cancer can cause narrowing of the esophagus , making it difficult or painful to swallow; and colorectal cancer may lead to narrowing or blockages in

150-474: A concern. This includes that studies have not found a consistent link between mobile phone radiation and cancer risk. The vast majority of cancers are non-hereditary (sporadic). Hereditary cancers are primarily caused by an inherited genetic defect. Less than 0.3% of the population are carriers of a genetic mutation that has a large effect on cancer risk and these cause less than 3–10% of cancer. Some of these syndromes include: certain inherited mutations in

200-566: A persistent fever . Shortness of breath, called dyspnea , is a common symptom of cancer and its treatment. The causes of cancer-related dyspnea can include tumors in or around the lung, blocked airways, fluid in the lungs, pneumonia, or treatment reactions including an allergic response . Treatment for dyspnea in patients with advanced cancer can include fans , bilevel ventilation, acupressure / reflexology and multicomponent nonpharmacological interventions . Some systemic symptoms of cancer are caused by hormones or other molecules produced by

250-452: A population is determined by the rate of cell proliferation minus the rate of cell death . Cell size depends on both cell growth and cell division, with a disproportionate increase in the rate of cell growth leading to production of larger cells and a disproportionate increase in the rate of cell division leading to production of many smaller cells. Cell proliferation typically involves balanced cell growth and cell division rates that maintain

300-539: A role. Oncoviruses (viruses that can cause human cancer) include: Bacterial infection may also increase the risk of cancer, as seen in Parasitic infections associated with cancer include: Radiation exposure such as ultraviolet radiation and radioactive material is a risk factor for cancer. Many non-melanoma skin cancers are due to ultraviolet radiation, mostly from sunlight. Sources of ionizing radiation include medical imaging and radon gas. Ionizing radiation

350-408: A roughly constant cell size in the exponentially proliferating population of cells. Cell proliferation occurs by combining cell growth with regular "G1- S - M -G2" cell cycles to produce many diploid cell progeny. In single-celled organisms, cell proliferation is largely responsive to the availability of nutrients in the environment (or laboratory growth medium ). In multicellular organisms,

400-416: Is about 2. The corresponding relative risk is 1.5 for lung cancer, and 1.9 for prostate cancer . For breast cancer, the relative risk is 1.8 with a first-degree relative having developed it at 50 years of age or older, and 3.3 when the relative developed it when being younger than 50 years of age. Taller people have an increased risk of cancer because they have more cells than shorter people. Since height

450-537: Is generally not a transmissible disease . Exceptions include rare transmissions that occur with pregnancies and occasional organ donors . However, transmissible infectious diseases such as hepatitis B , Epstein-Barr virus , Human Papilloma Virus and HIV , can contribute to the development of cancer. Exposure to particular substances have been linked to specific types of cancer. These substances are called carcinogens . Tobacco smoke , for example, causes 90% of lung cancer. Tobacco use can cause cancer throughout

500-413: Is genetically determined to a large extent, taller people have a heritable increase of cancer risk. Some substances cause cancer primarily through their physical, rather than chemical, effects. A prominent example of this is prolonged exposure to asbestos , naturally occurring mineral fibers that are a major cause of mesothelioma (cancer of the serous membrane ) usually the serous membrane surrounding

550-637: Is more common in Japan due to its high-salt diet while colon cancer is more common in the United States. Immigrant cancer profiles mirror those of their new country, often within one generation. Worldwide, approximately 18% of cancer deaths are related to infectious diseases . This proportion ranges from a high of 25% in Africa to less than 10% in the developed world. Viruses are the usual infectious agents that cause cancer but bacteria and parasites may also play

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600-403: Is not inherited , such as lifestyle, economic, and behavioral factors and not merely pollution. Common environmental factors that contribute to cancer death include tobacco use (25–30%), diet and obesity (30–35%), infections (15–20%), radiation (both ionizing and non-ionizing, up to 10%), lack of physical activity , and pollution. Psychological stress does not appear to be a risk factor for

650-474: Is not a particularly strong mutagen . Residential exposure to radon gas, for example, has similar cancer risks as passive smoking . Radiation is a more potent source of cancer when combined with other cancer-causing agents, such as radon plus tobacco smoke. Radiation can cause cancer in most parts of the body, in all animals and at any age. Children are twice as likely to develop radiation-induced leukemia as adults; radiation exposure before birth has ten times

700-427: Is predominantly used in the production of Teflon , is known to cause two kinds of cancer. Chemotherapy drugs such as platinum-based compounds are carcinogens that increase the risk of secondary cancers Azathioprine , an immunosuppressive medication , is a carcinogen that can cause primary tumors to develop. Diet, physical inactivity , and obesity are related to up to 30–35% of cancer deaths. In

750-577: Is sometimes used interchangeably among scientists with the term cytokine . Historically, cytokines were associated with hematopoietic (blood and lymph forming) cells and immune system cells (e.g., lymphocytes and tissue cells from spleen , thymus , and lymph nodes ). For the circulatory system and bone marrow in which cells can occur in a liquid suspension and not bound up in solid tissue , it makes sense for them to communicate by soluble, circulating protein molecules . However, as different lines of research converged, it became clear that some of

800-770: Is the cause of about 22% of cancer deaths. Another 10% are due to obesity , poor diet , lack of physical activity or excessive alcohol consumption . Other factors include certain infections, exposure to ionizing radiation , and environmental pollutants. Infection with specific viruses, bacteria and parasites is an environmental factor causing approximately 16–18% of cancers worldwide. These infectious agents include Helicobacter pylori , hepatitis B , hepatitis C , human papillomavirus infection , Epstein–Barr virus , Human T-lymphotropic virus 1 , Kaposi's sarcoma-associated herpesvirus and Merkel cell polyomavirus . Human immunodeficiency virus (HIV) does not directly cause cancer but it causes immune deficiency that can magnify

850-457: Is then typically further investigated by medical imaging and confirmed by biopsy . The risk of developing certain cancers can be reduced by not smoking, maintaining a healthy weight, limiting alcohol intake, eating plenty of vegetables, fruits, and whole grains , vaccination against certain infectious diseases, limiting consumption of processed meat and red meat , and limiting exposure to direct sunlight. Early detection through screening

900-409: Is useful for cervical and colorectal cancer . The benefits of screening for breast cancer are controversial. Cancer is often treated with some combination of radiation therapy , surgery, chemotherapy and targeted therapy . Pain and symptom management are an important part of care. Palliative care is particularly important in people with advanced disease. The chance of survival depends on

950-495: The Insulin / IGF-1 family, which are also considered growth factors, and that function to promote cell proliferation in cells throughout the body that are capable of doing so. Uncontrolled cell proliferation, leading to an increased proliferation rate, or a failure of cells to arrest their proliferation at the normal time, is a cause of cancer . Cancer Cancer is a group of diseases involving abnormal cell growth with

1000-402: The bowel , affecting bowel habits. Masses in breasts or testicles may produce observable lumps. Ulceration can cause bleeding that can lead to symptoms such as coughing up blood (lung cancer), anemia or rectal bleeding (colon cancer), blood in the urine (bladder cancer), or abnormal vaginal bleeding (endometrial or cervical cancer). Although localized pain may occur in advanced cancer,

1050-584: The immune system and endocrine system . More than half of the effect from the diet is due to overnutrition (eating too much), rather than from eating too few vegetables or other healthful foods. Some specific foods are linked to specific cancers. A high-salt diet is linked to gastric cancer . Aflatoxin B1 , a frequent food contaminant, causes liver cancer. Betel nut chewing can cause oral cancer. National differences in dietary practices may partly explain differences in cancer incidence. For example, gastric cancer

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1100-452: The lungs , liver , brain, and the bones . While some cancers can be cured if detected early, metastatic cancer is more difficult to treat and control. Nevertheless, some recent treatments are demonstrating encouraging results. The majority of cancers, some 90–95% of cases, are due to genetic mutations from environmental and lifestyle factors. The remaining 5–10% are due to inherited genetics . Environmental refers to any cause that

1150-576: The six hallmarks of cancer . These characteristics are required to produce a malignant tumor. They include: The progression from normal cells to cells that can form a detectable mass to cancer involves multiple steps known as malignant progression. When cancer begins, it produces no symptoms. Signs and symptoms appear as the mass grows or ulcerates . The findings that result depend on cancer's type and location. Few symptoms are specific . Many frequently occur in individuals who have other conditions. Cancer can be difficult to diagnose and can be considered

1200-460: The tumor microenvironment . Oncogenes build up an inflammatory pro-tumorigenic microenvironment. Hormones also play a role in the development of cancer by promoting cell proliferation . Insulin-like growth factors and their binding proteins play a key role in cancer cell proliferation, differentiation and apoptosis , suggesting possible involvement in carcinogenesis. Hormones are important agents in sex-related cancers, such as cancer of

1250-745: The United States have mirrored smoking patterns, with increases in smoking followed by dramatic increases in lung cancer death rates and, more recently, decreases in smoking rates since the 1950s followed by decreases in lung cancer death rates in men since 1990. In Western Europe, 10% of cancers in males and 3% of cancers in females are attributed to alcohol exposure, especially liver and digestive tract cancers. Cancer from work-related substance exposures may cause between 2 and 20% of cases, causing at least 200,000 deaths. Cancers such as lung cancer and mesothelioma can come from inhaling tobacco smoke or asbestos fibers, or leukemia from exposure to benzene . Exposure to perfluorooctanoic acid (PFOA), which

1300-479: The United States, excess body weight is associated with the development of many types of cancer and is a factor in 14–20% of cancer deaths. A UK study including data on over 5 million people showed higher body mass index to be related to at least 10 types of cancer and responsible for around 12,000 cases each year in that country. Physical inactivity is believed to contribute to cancer risk, not only through its effect on body weight but also through negative effects on

1350-414: The body (such as through inhalation) and require years of exposure to produce cancer. Physical trauma resulting in cancer is relatively rare. Claims that breaking bones resulted in bone cancer, for example, have not been proven. Similarly, physical trauma is not accepted as a cause for cervical cancer, breast cancer or brain cancer. One accepted source is frequent, long-term application of hot objects to

1400-404: The body including in the mouth and throat, larynx , esophagus , stomach, bladder, kidney, cervix, colon/rectum, liver and pancreas . Tobacco smoke contains over fifty known carcinogens, including nitrosamines and polycyclic aromatic hydrocarbons . Tobacco is responsible for about one in five cancer deaths worldwide and about one in three in the developed world. Lung cancer death rates in

1450-401: The body. It is possible that repeated burns on the same part of the body, such as those produced by kanger and kairo heaters (charcoal hand warmers ), may produce skin cancer, especially if carcinogenic chemicals are also present. Frequent consumption of scalding hot tea may produce esophageal cancer. Generally, it is believed that cancer arises, or a pre-existing cancer is encouraged, during

1500-527: The breast, endometrium , prostate, ovary and testis and also of thyroid cancer and bone cancer . For example, the daughters of women who have breast cancer have significantly higher levels of estrogen and progesterone than the daughters of women without breast cancer. These higher hormone levels may explain their higher risk of breast cancer, even in the absence of a breast-cancer gene. Similarly, men of African ancestry have significantly higher levels of testosterone than men of European ancestry and have

1550-457: The developing world. The global total economic costs of cancer were estimated at US$ 1.16 trillion (equivalent to $ 1.62 trillion in 2023) per year as of 2010 . The word comes from the ancient Greek [καρκίνος] Error: {{Transliteration}}: transliteration text not Latin script ( help ) , meaning 'crab' and 'tumor'. Greek physicians Hippocrates and Galen , among others, noted the similarity of crabs to some tumors with swollen veins. The word

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1600-455: The effect. Medical use of ionizing radiation is a small but growing source of radiation-induced cancers. Ionizing radiation may be used to treat other cancers, but this may, in some cases, induce a second form of cancer. It is also used in some kinds of medical imaging . Prolonged exposure to ultraviolet radiation from the sun can lead to melanoma and other skin malignancies. Clear evidence establishes ultraviolet radiation, especially

1650-445: The genes BRCA1 and BRCA2 with a more than 75% risk of breast cancer and ovarian cancer , and hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome), which is present in about 3% of people with colorectal cancer , among others. Statistically for cancers causing most mortality, the relative risk of developing colorectal cancer when a first-degree relative (parent, sibling or child) has been diagnosed with it

1700-479: The initial tumor is usually painless. Some cancers can cause a buildup of fluid within the chest or abdomen . Systemic symptoms may occur due to the body's response to the cancer. This may include fatigue, unintentional weight loss, or skin changes. Some cancers can cause a systemic inflammatory state that leads to ongoing muscle loss and weakness, known as cachexia . Some cancers, such as Hodgkin's disease , leukemias , and liver or kidney cancers , can cause

1750-481: The last two decades, growth factors have been increasingly used in the treatment of hematologic and oncologic diseases and cardiovascular diseases such as: Cell proliferation Stem cells undergo cell proliferation to produce proliferating "transit amplifying" daughter cells that later differentiate to construct tissues during normal development and tissue growth, during tissue regeneration after damage , or in cancer . The total number of cells in

1800-441: The lungs. Other substances in this category, including both naturally occurring and synthetic asbestos-like fibers, such as wollastonite , attapulgite , glass wool and rock wool , are believed to have similar effects. Non-fibrous particulate materials that cause cancer include powdered metallic cobalt and nickel and crystalline silica ( quartz , cristobalite and tridymite ). Usually, physical carcinogens must get inside

1850-496: The non-ionizing medium wave UVB , as the cause of most non-melanoma skin cancers , which are the most common forms of cancer in the world. Non-ionizing radio frequency radiation from mobile phones, electric power transmission and other similar sources has been described as a possible carcinogen by the World Health Organization 's International Agency for Research on Cancer . Evidence, however, has not supported

1900-462: The onset of cancer, though it may worsen outcomes in those who already have cancer. Environmental or lifestyle factors that caused cancer to develop in an individual can be identified by analyzing mutational signatures from genomic sequencing of tumor DNA. For example, this can reveal if lung cancer was caused by tobacco smoke, if skin cancer was caused by UV radiation, or if secondary cancers were caused by previous chemotherapy treatment. Cancer

1950-425: The original is called the primary tumor. Almost all cancers can metastasize. Most cancer deaths are due to cancer that has metastasized. Metastasis is common in the late stages of cancer and it can occur via the blood or the lymphatic system or both. The typical steps in metastasis are: Different types of cancers tend to metastasize to particular organs. Overall, the most common places for metastases to occur are

2000-404: 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. Tobacco use

2050-869: The previous decade increases of 26% and 21%, respectively. The most common types of cancer in males are lung cancer , prostate cancer , colorectal cancer , and stomach cancer . In females, the most common types are breast cancer , colorectal cancer, lung cancer, and cervical cancer . If skin cancer other than melanoma were included in total new cancer cases each year, it would account for around 40% of cases. In children, acute lymphoblastic leukemia and brain tumors are most common, except in Africa, where non-Hodgkin lymphoma occurs more often. In 2012, about 165,000 children under 15 years of age were diagnosed with cancer. The risk of cancer increases significantly with age, and many cancers occur more commonly in developed countries. Rates are increasing as more people live to an old age and as lifestyle changes occur in

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2100-542: The process of cell proliferation is tightly controlled by gene regulatory networks encoded in the genome and executed mainly by transcription factors including those regulated by signal transduction pathways elicited by growth factors during cell–cell communication in development . Recently it has been also demonstrated that cellular bicarbonate metabolism, which is responsible for cell proliferation, can be regulated by mTORC1 signaling. In addition, intake of nutrients in animals can induce circulating hormones of

2150-403: The process of healing, rather than directly by the trauma. However, repeated injuries to the same tissues might promote excessive cell proliferation, which could then increase the odds of a cancerous mutation. Chronic inflammation has been hypothesized to directly cause mutation. Inflammation can contribute to proliferation, survival, angiogenesis and migration of cancer cells by influencing

2200-618: The risk due to other infections, sometimes up to several thousand fold (in the case of Kaposi's sarcoma ). Importantly, vaccination against hepatitis B and human papillomavirus have been shown to nearly eliminate risk of cancers caused by these viruses in persons successfully vaccinated prior to infection. These environmental factors act, at least partly, by changing the genes of a cell. Typically, many genetic changes are required before cancer develops. Approximately 5–10% of cancers are due to inherited genetic defects. Cancer can be detected by certain signs and symptoms or screening tests. It

2250-670: The same signaling proteins which the hematopoietic and immune systems use were also being used by all sorts of other cells and tissues, during development and in the mature organism. While growth factor implies a positive effect on cell proliferation , cytokine is a neutral term with respect to whether a molecule affects proliferation. While some cytokines can be growth factors, such as G-CSF and GM-CSF , others have an inhibitory effect on cell growth or cell proliferation. Some cytokines, such as Fas ligand , are used as "death" signals; they cause target cells to undergo programmed cell death or apoptosis . The nerve growth factor (NGF)

2300-401: The surface of their target cells . They often promote cell differentiation and maturation, which varies between growth factors. For example, epidermal growth factor (EGF) enhances osteogenic differentiation ( osteogenesis or bone formation), while fibroblast growth factors and vascular endothelial growth factors stimulate blood vessel differentiation ( angiogenesis ). Growth factor

2350-400: The tumor, known as paraneoplastic syndromes . Common paraneoplastic syndromes include hypercalcemia , which can cause altered mental state , constipation and dehydration, or hyponatremia , which can also cause altered mental status, vomiting, headaches, or seizures. Metastasis is the spread of cancer to other locations in the body. The dispersed tumors are called metastatic tumors, while

2400-461: The type of cancer and extent of disease at the start of treatment. In children under 15 at diagnosis, the five-year survival rate in the developed world is on average 80%. For cancer in the United States, the average five-year survival rate is 66% for all ages. In 2015, about 90.5 million people worldwide had cancer. In 2019, annual cancer cases grew by 23.6 million people, and there were 10 million deaths worldwide, representing over

2450-565: Was first discovered by Rita Levi-Montalcini , which won her a Nobel Prize in Physiology or Medicine . Individual growth factor proteins tend to occur as members of larger families of structurally and evolutionarily related proteins. There are many families, some of which are listed below: The alpha granules in blood platelets contain growth factors PDGF, IGF-1, EGF, and TGF-β which begin healing of wounds by attracting and activating macrophages , fibroblasts , and endothelial cells . For

2500-477: Was introduced in English in the modern medical sense around 1600. Cancers comprise a large family of diseases that involve abnormal cell growth with the potential to invade or spread to other parts of the body. They form a subset of neoplasms . A neoplasm or tumor is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely. All tumor cells show

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