Cancer in the context of "List of chemotherapeutic agents"

Preventive healthcare, or prophylaxis, is the application of healthcare measures to prevent diseases. Disease and disability are affected by environmental factors, genetic predisposition, disease agents, and lifestyle choices, and are dynamic processes that begin before individuals realize they are affected. Disease prevention relies on anticipatory actions that can be categorized as primal, primary, secondary, and tertiary prevention.

Each year, millions of people die of preventable causes. A 2004 study showed that about half of all deaths in the United States in 2000 were due to preventable behaviors and exposures. Leading causes included cardiovascular disease, chronic respiratory disease, unintentional injuries, diabetes, and certain infectious diseases. This same study estimates that 400,000 people die each year in the United States due to poor diet and a sedentary lifestyle. According to estimates made by the World Health Organization (WHO), about 55 million people died worldwide in 2011, and two-thirds of these died from non-communicable diseases, including cancer, diabetes, and chronic cardiovascular and lung diseases. This is an increase from the year 2000, during which 60% of deaths were attributed to these diseases.)

Cell biology, cellular biology, or cytology, is the branch of biology that studies the structure, function, and behavior of the cells. All organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of an organism. Cell biology encompasses both prokaryotic and eukaryotic cells, with subtopics including the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition.

The study of cells is performed using microscopy techniques, cell culture, and cell fractionation. These are used for research into how cells function, which ultimately gives insight into larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences and is essential for research in biomedical fields such as cancer, and other diseases. Research in cell biology is interconnected to other fields such as genetics, molecular genetics, molecular biology, medical microbiology, immunology, and cytochemistry.

This is a list of the largest known epidemics and pandemics caused by an infectious disease in humans. Widespread non-communicable diseases such as cardiovascular disease and cancer are not included. An epidemic is the rapid spread of disease to a large number of people in a given population within a short period of time; in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic. Due to the long time spans, the first plague pandemic (6th century – 8th century) and the second plague pandemic (14th century – early 19th century) are shown by individual outbreaks, such as the Plague of Justinian (first pandemic) and the Black Death (second pandemic).

Infectious diseases with high prevalence are listed separately (sometimes in addition to their epidemics), such as malaria, which may have killed 50–60 million people.

Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum (photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. Instead of producing charged ions when passing through matter, non-ionizing electromagnetic radiation has sufficient energy only for excitation (the movement of an electron to a higher energy state). Non-ionizing radiation is not a significant health risk except in circumstances of prolonged exposure to higher frequency non-ionizing radiation or high power densities as may occur in laboratories and industrial workplaces. Non-ionizing radiation is used in various technologies, including radio broadcasting, telecommunications, medical imaging, and heat therapy.

In contrast, ionizing radiation has a higher frequency and shorter wavelength than non-ionizing radiation, and can be a serious health hazard: exposure to it can cause burns, radiation sickness, many kinds of cancer, and genetic damage. Using ionizing radiation requires elaborate radiological protection measures, which in general are not required with non-ionizing radiation.

A gene product is the biochemical material, either RNA or protein, resulting from the expression of a gene. A measurement of the amount of gene product is sometimes used to infer how active a gene is. Abnormal amounts of gene product can be correlated with disease-causing alleles, such as the overactivity of oncogenes, which can cause cancer.A gene is defined as "a hereditary unit of DNA that is required to produce a functional product". Regulatory elements include:

• Promoter region
• TATA box
• Polyadenylation sequences
• Enhancers

These elements work in combination with the open reading frame to create a functional product. This product may be transcribed and be functional as RNA or is translated from mRNA to a protein to be functional in the cell.

In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from substitution, insertion or deletion of segments of DNA due to mobile genetic elements.

Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source of all genetic variation, providing the raw material on which evolutionary forces such as natural selection can act.

Cervical cancer is a type of cancer that develops in the cervix or in any layer of the wall of the cervix. It is due to the abnormal growth of cells that can invade or spread to other parts of the body. Early on, typically no symptoms are seen. Later symptoms may include abnormal vaginal bleeding, pelvic pain or pain during sexual intercourse. While bleeding after sex may not be serious, it may also indicate the presence of cervical cancer.

Virtually all cervical cancer cases (99%) are linked to genital human papillomavirus infection (HPV); most who have had HPV infections, however, do not develop cervical cancer. HPV 16 and 18 strains are responsible for approximately 70% of cervical cancer cases globally and nearly 50% of high-grade cervical pre-cancers. Minor risk factors include smoking, a weak immune system, birth control pills, starting sex at a young age, and having many sexual partners. Genetic factors also contribute to cervical cancer risk. Cervical cancer typically develops from precancerous changes called cervical intraepithelial neoplasia over 10 to 20 years. About 75% of cervical cancers are squamous cell carcinomas, 20-25% are adenocarcinoma, 3% are adenosquamous carcinomas, and less than 1% are small cell neuroendocrine tumors of the cervix. Diagnosis is typically by cervical screening followed by a biopsy. Medical imaging is then done to determine whether or not the cancer has spread beyond the cervix.

Opium (also known as poppy tears, or Lachryma papaveris) is the dried latex obtained from the seed capsules of the opium poppy Papaver somniferum. Approximately 12 percent of opium is made up of the analgesic alkaloid morphine, which is processed chemically to produce heroin and other synthetic opioids for medicinal use and for the illegal drug trade. Opium's main psychoactive alkaloids, primarily morphine, act on μ-opioid receptors, causing analgesia and addiction with long-term use leading to tolerance, dependence, and increased cancer risk. The latex also contains the closely related opiates codeine and thebaine, and non-analgesic alkaloids such as papaverine and noscapine. The traditional, labor-intensive method of obtaining the latex is to scratch ("score") the immature seed pods (fruits) by hand; the latex leaks out and dries to a sticky yellowish residue that is later scraped off and dehydrated.

The English word for opium is borrowed from Latin, which in turn comes from Ancient Greek: ὄπιον (ópion), a diminutive of ὀπός (opós, "juice of a plant"). The word meconium (derived from the Greek for "opium-like", but now used to refer to newborn stools) historically referred to related, weaker preparations made from other parts of the opium poppy or different species of poppies. The Mediterranean region holds the earliest archaeological evidence of human use of opium poppies dating back to before 5000 BCE, with cultivation beginning around 3400 BCE in Mesopotamia. Opium was widely used for food, medicine, ritual, and as a painkiller throughout ancient civilizations including Greece, Egypt, and Islamic societies up to medieval times.

On 11 March 2011, a major nuclear accident started at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The direct cause was the Tōhoku earthquake and tsunami, which resulted in electrical grid failure and damaged nearly all of the power plant's backup energy sources. The subsequent inability to sufficiently cool reactors after shutdown compromised containment and resulted in the release of radioactive contaminants into the surrounding environment. The accident was rated seven (the maximum severity) on the International Nuclear Event Scale by Nuclear and Industrial Safety Agency, following a report by the JNES (Japan Nuclear Energy Safety Organization). It is regarded as the worst nuclear incident since the Chernobyl disaster in 1986, which was also rated a seven on the International Nuclear Event Scale.

According to the United Nations Scientific Committee on the Effects of Atomic Radiation, "no adverse health effects among Fukushima residents have been documented that are directly attributable to radiation exposure from the Fukushima Daiichi nuclear plant accident". Insurance compensation was paid for one death from lung cancer, but this does not prove a causal relationship between radiation and the cancer. Six other persons have been reported as having developed cancer or leukemia. Two workers were hospitalized because of radiation burns, and several other people sustained physical injuries as a consequence of the accident.

Smoking cessation, usually called quitting smoking or stopping smoking, is the process of discontinuing tobacco smoking. Tobacco smoke contains nicotine, which is addictive and can cause dependence. As a result, nicotine withdrawal often makes the process of quitting difficult.

Smoking is the leading cause of preventable death and a global public health concern. Tobacco use leads most commonly to diseases affecting the heart and lungs, with smoking being a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), emphysema, and various types and subtypes of cancers (particularly lung cancer, cancers of the oropharynx, larynx, and mouth, esophageal and pancreatic cancer). Smoking cessation significantly reduces the risk of dying from smoking-related diseases. The risk of heart attack in a smoker decreases by 50% after one year of cessation. Similarly, the risk of lung cancer decreases by 50% in 10 years of cessation

Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess body fat has accumulated to such an extent that it can have negative effects on health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over 30 kg/m; the range 25–30 kg/m is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis.

Obesity has individual, socioeconomic, and environmental causes. Some known causes are diet, low physical activity, automation, urbanization, genetic susceptibility, medications, mental disorders, economic policies, endocrine disorders, and exposure to endocrine-disrupting chemicals.

Liver cancer, also known as hepatic cancer, primary hepatic cancer, or primary hepatic malignancy, is cancer that starts in the liver. Liver cancer can be primary in which the cancer starts in the liver, or it can be liver metastasis, or secondary, in which the cancer spreads from elsewhere in the body to the liver. Liver metastasis is the more common of the two liver cancers. Instances of liver cancer are increasing globally.

Primary liver cancer is globally the sixth-most frequent cancer and the fourth-leading cause of death from cancer. In 2018, it occurred in 841,000 people and resulted in 782,000 deaths globally. Higher rates of liver cancer occur where hepatitis B and C are common, including Asia and sub-Saharan Africa. Males are more often affected with hepatocellular carcinoma (HCC) than females. Diagnosis is most frequent among those 55 to 65 years old.

The Epstein–Barr virus (EBV), also known as human herpesvirus 4 (HHV-4), is one of the nine known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. EBV is a double-stranded DNA virus. EBV is the first identified oncogenic virus, a virus that can cause cancer. EBV establishes a permanent infection in human B cells. It uncommonly causes infectious mononucleosis and is also tightly linked to many malignant diseases (cancers and autoimmune diseases). Various vaccine formulations have been tested in humans and other animals; however, none of them were able to prevent EBV infection, thus, no vaccine has been approved to date.

Infectious mononucleosis ("mono" or "glandular fever"), is characterized by extreme fatigue, fever, sore throat, and swollen lymph nodes. EBV is also associated with various non-malignant, premalignant, and malignant EBV-associated lymphoproliferative diseases such as Burkitt lymphoma, hemophagocytic lymphohistiocytosis, and Hodgkin's lymphoma; non-lymphoid malignancies such as gastric cancer and nasopharyngeal carcinoma; and conditions associated with human immunodeficiency virus such as hairy leukoplakia and central nervous system lymphomas. The virus is also associated with the childhood disorders of Alice in Wonderland syndrome and acute cerebellar ataxia and, by some evidence, higher risks of developing certain autoimmune diseases, especially dermatomyositis, systemic lupus erythematosus, rheumatoid arthritis, and Sjögren's syndrome. About 200,000 cancer cases globally per year are thought to be attributable to EBV. In 2022, a large study following 10 million active US military over 20 years suggested EBV as the leading cause of multiple sclerosis (MS), with a recent EBV infection causing a 32-fold increase in MS risk development.

Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription dietary supplement. As a therapy, it is used to prevent and treat scurvy, a disease caused by vitamin C deficiency.

Vitamin C is an essential nutrient involved in the repair of tissue, the formation of collagen, and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant. Vitamin C may be taken by mouth or by intramuscular, subcutaneous or intravenous injection. Various health claims exist on the supposition that moderate vitamin C deficiency increases disease risk, such as for the common cold, cancer or COVID-19. There are also claims of benefits from vitamin C supplementation in excess of the recommended dietary intake for people who are not considered vitamin C deficient. Vitamin C is generally well tolerated. Large doses may cause gastrointestinal discomfort, headache, trouble sleeping, and flushing of the skin. The United States National Academy of Medicine recommends against consuming large amounts.

Exercise or working out is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardiovascular system, hone athletic skills, improve health, or simply for enjoyment. Many people choose to exercise outdoors where they can congregate in groups, socialize, and improve well-being as well as mental health.

In terms of health benefits, usually, 150 minutes (2 hours and 30 minutes) of moderate-intensity exercise per week is recommended for reducing the risk of health problems. At the same time, even doing a small amount of exercise is healthier than doing none. Only doing an hour and a quarter (11 minutes/day) of exercise could reduce the risk of early death, cardiovascular disease, stroke, and cancer.

Soot (/sʊt/ suut) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. Soot is considered a hazardous substance with carcinogenic properties. Most broadly, the term includes all the particulate matter produced by this process, including black carbon and residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke classified as cokes or char. It can include polycyclic aromatic hydrocarbons and heavy metals like mercury.

Soot causes various types of cancer and lung disease.

A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the immune system to recognize the agent as a threat, destroy it, and recognize further and destroy any of the microorganisms associated with that agent that it may encounter in the future.

Vaccines can be prophylactic (to prevent or alleviate the effects of a future infection by a natural or "wild" pathogen), or therapeutic (to fight a disease that has already occurred, such as cancer). Some vaccines offer full sterilizing immunity, in which infection is prevented.