Self-examinations can be used for cancers of the mouth, breast, skin, and testis.
Cancer has been called "a disease of cell division—a failure of cell division control.
The concept that medications could be used to prevent cancer is an attractive one, and many high-quality clinical trials support the use of such chemoprevention in defined circumstances.
Greater than 30 percent of cancer is preventable via avoiding risk factors including: tobacco, overweight, or obesity, low fruit and vegetable intake, physical inactivity, alcohol, sexually transmitted infections, and air pollution.
The three properties of cancers (uncontrolled growth, invasion, and metastasis) differentiate them from benign tumors and benign neoplasms.
The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease.
Radiation, designed to kill cancer cells, can be applied externally or internally.
Despite this substantial investment, the country has seen a five percent decrease in the cancer death rate (adjusting for size and age of the population) between 1950 and 2005.
Neoplasm is often used interchangeably with words such as tumor and cancer.
Many treatment/management options for cancer exist including: chemotherapy, radiation therapy, surgery, immunotherapy, monoclonal antibody therapy, hormone therapy, and other methods.
Some cancer-promoting genetic abnormalities are inherited, and thus present in all cells from birth, having occurred through errors in DNA replication.
The margin can be as little as 1 mm for basal cell cancer using CCPDMA or Mohs surgery, to several centimeters for aggressive cancers.
Cancers are classified according to the tissue presumed to be the origin of the tumor, based on the resemblance of the tumorous cells to the normal cells in the tissue and the location.
The genetic basis of cancer was recognized in 1902 by the German zoologist Theodor Boveri, professor of zoology at Munich and later in Wьrzburg.
A coronal CT scan showing malignant cancer of the lung sac.
Malignant tumors (cancers) are usually named using -carcinoma, -sarcoma or -blastoma as a suffix, with the Latin or Greek word for the organ of origin as the root.
Glue and varnish workers have an increased incidence of leukemia; PVC manufacturing is linked to liver cancer; and uranium mining and radiology is linked to bone and bone marrow cancer, as well as lung cancer.
Folic acid supplementation has not been found effective in preventing colon cancer and may increase colon polyps.
Any multicellular organism with diverse tissues, even plants, can acquire cancer.
The German professor Wilhelm Fabry believed that breast cancer was caused by a milk clot in a mammary duct.
Early identification of inherited genetic risk for cancer, along with cancer-preventing interventions such as surgery or enhanced surveillance, can be lifesaving for high-risk individuals.
Advances in cancer research have made a vaccine designed to prevent cancer available.
Follow up procedures used to diagnose prostate cancer (prostate biopsy) may cause side effects, including bleeding and infection.
Non-ionizing radio frequency radiation from mobile phones and other similar RF sources has also been proposed as a cause of cancer.
Genetic testing for high-risk individuals is already available for certain cancer-related genetic mutations.
Her ground-breaking work on cancer epidemiology was carried on by Richard Doll and Austin Bradford Hill, who published "Lung Cancer and Other Causes of Death In Relation to Smoking.
The first cause of cancer was identified by British surgeon Percivall Pott, who discovered in 1775 that cancer of the scrotum was a common disease among chimney sweeps.
Less than ten percent of all cancers are considered to purely hereditary.
Every year, at least 200,000 people die worldwide from cancer related to their workplace.
Studies have shown, for example, that the fiber in fruits and vegetables correlates with reduction in the risk of colon cancer.
The American Cancer Society estimates that approximately 40 percent of cancer deaths in 1998 were due to tobacco and excessive alcohol use and another one-third of deaths were related to diet and nutrition.
Chemotherapy—the use of drugs to kill cancer cells—can be used to destroy cancer cells that are hard to detect and that have spread.
Cancer research is the scientific effort to understand disease processes and discover possible therapies.
Experimental and epidemiological data imply a causative role for viruses and they appear to be the second most important risk factor for cancer development in humans, exceeded only by tobacco usage.
Most forms of cancer are sporadic, meaning that there is no inherited cause of the cancer.
Such chemicals may promote cancers through stimulating the rate of cell division rather than mutation.
Despite frequent reports of particular substances and foods having a beneficial or detrimental effect on cancer risk, few of these have an established link to cancer.
The women on the low fat diet were found to have a markedly lower risk of breast cancer recurrence, in the interim report of December, 2006.
The errors which cause cancer are often self-amplifying, eventually compounding at an exponential rate.
Ionizing radiation from nuclear material is another source of cancer.
Similarly, cervical cytology testing (using the Pap smear) leads to the identification and excision of precancerous lesions.
The American Cancer Society reports that over one-third (35 percent) of all cancer deaths in the United States are related to diet and nutrition.
The consensus on diet and cancer is that obesity increases the risk of developing cancer.
Screening for cancer can lead to earlier diagnosis in specific cases.
Cancers essentially are caused by abnormalities in the genetic material of the transformed cells leading to uncontrolled cell growth and invasion of other tissues.
Cancer is thus a progressive disease, and these progressive errors slowly accumulate until a cell begins to act contrary to its function in the organism.
Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy, and radiotherapy.
Particular substances have been linked to specific types of cancer.
Excepting the rare transmissions that occur with pregnancies and only a marginal few organ donors, cancer is generally not a transmissible disease.
Worldwide, liver cancer is one of the most common, and most deadly, cancers due to a huge burden of viral hepatitis transmission and disease.
Tobacco is responsible for about one in three of all cancer deaths in the developed world, and about one in five worldwide.
Cancer can occur in children and adolescents, but it is uncommon (about 150 cases per million in the U.S.), with leukemia the most common.
Through the centuries it was discovered that cancer could occur anywhere in the body, but humor-theory based treatment remained popular until the nineteenth century and the discovery of cells.
The most prominent example is the link between chronic infection of the wall of the stomach with Helicobacter pylori and gastric cancer.
Here, the adjective ductal refers to the appearance of the cancer under the microscope, resembling normal breast ducts.
Research suggests the compounds in medicinal mushrooms most responsible for up-regulating the immune system and providing an anti-cancer effect, are a diverse collection of polysaccharide compounds, particularly beta-glucans.
African-Americans are more likely to develop cancer and die of cancer than whites.
Richard Doll left the London Medical Research Center (MRC), to start the Oxford unit for cancer epidemiology in 1968.
The risk of cancer increases with age, with most cases occurring in people older than 65 years of age.
Many governmental and charitable organizations have been established to help patients cope with cancer.
Most cancers can be treated and some forced into remission, depending on the specific type, location, and stage.
Screening for cancer is controversial in cases when it is not yet known if the test actually saves lives.
Cancer patient treatment and studies were restricted to individual physicians' practices until World War II, when medical research centers discovered that there were large international differences in disease incidence.
Normally, these two divisions of the autonomic nervous systems have opposite but complementary actions, but in the control of saliva they work together.
A number of different screening tests have been developed for different malignancies, including for cancers of the breast, rectum, colon, prostate, testis, tongue, skin, and mouth at early stages.
Testicular self-examination is recommended for men beginning at the age of 15 years to detect testicular cancer.
Carriers of genetic mutations that increase risk for cancer incidence can undergo enhanced surveillance, chemoprevention, or risk-reducing surgery.
Tobacco smoking is associated with many forms of cancer, and causes eighty to ninety percent of lung cancer cases.
Cancer is a diverse class of diseases, which differ widely in their causes and biology.
Complete removal of the cancer without damage to the rest of the body is the goal of treatment.
Some studies have also demonstrated potential links between some forms of cancer and high consumption of refined sugars and other simple carbohydrates.
The human papilloma virus, noted above as an infectious cause of cervical cancer, is sexually transmitted disease.
The excessive consumption of fat, leading to obesity, is linked to cancers of the colon, rectum, pancreas, breast, prostate, ovaries, uterus, and gall bladder.
By definition, cancer is a disease of the genes.
Cancer may be a common or uncommon cause of each item.
Smoking also has been linked, via decades of research, to cancers of the upper respiratory tract, larynx, head, neck, stomach, bladder, kidney, esophagus and pancreas.
Tumor suppressor genes are often disabled by cancer-promoting genetic changes.
Some mushrooms offer an anti-cancer effect, which is thought to be linked to their ability to up-regulate the immune system.
Progressive and disseminated malignant disease has a substantial impact on a cancer patient's quality of life, and many cancer treatments (such as chemotherapy) may have severe side-effects.
Cancer, whether forming or tumor or not, is malignant.
Finasteride, a 5-alpha-reductase inhibitor, has been shown to lower the risk of prostate cancer, though it seems to mostly prevent low-grade tumors.
Counseling can provide emotional support to cancer patients and help them better understand their illness.
A low-fat diet and exercise, which help to control weight, are considered to reduce the risk of breast, colon, and endometrial cancer.
Over time, such testing has been followed by a dramatic reduction of cervical cancer incidence and mortality.
Vaccines are used to boost the bodies immune system and help the immune cells to identify and specifically destroy the cancer cells.
Supported and admired by Louis XIV, Lully often cast the king in his ballets.
Currently, most cancer deaths caused by occupational risk factors occur in the developed world.
Particular dietary practices often explain differences in cancer incidence in different countries (e.g.
Cancer is the second leading cause of death globally, and was responsible for 8.8 million deaths in 2015.
The Dutch professor Francois de la Boe Sylvius, a follower of Descartes, believed that all disease was the outcome of chemical processes, and that acidic lymph fluid was the cause of cancer.
Similarly, for breast cancer, there have been criticisms that breast screening programs in some countries may not be worthwhile overall.
Daily use of tamoxifen, a selective estrogen receptor modulator (SERM), typically for 5 years, has been demonstrated to reduce the risk of developing breast cancer in high-risk women by about fifty percent.
Known as "a disease of the genes," some cancers have an hereditary basis whereby an individual inherits faulty DNA from his or her parents, perhaps due to an error in replication of the DNA.
A cancer may be suspected for a variety of reasons, but the definitive diagnosis of most malignancies must be confirmed by histological examination of the cancerous cells by a pathologist.
Self-examinations can be used for cancers of the mouth, breast, skin, and testis.
Cancer is fundamentally a disease of regulation of tissue growth.
The main use of the term neoplasm is in medical statistics that categorize deaths or other events, in which case neoplasm is typically the category that includes cancer statistics.
Cancer affects people at all ages, with the risk for most types increasing with age.
gastric cancer is more common in Japan, while colon cancer is more common in the United States.).
Cervical cancer screening via the Pap smear has the best cost-benefit profile of all the common forms of cancer screening from a public health perspective.
Surgery is used to remove the visible tumor and is effective when the cancer is small and confined.
Cancer survivors may also be more likely to comply with recommended screening, and thus may be more likely than average to detect cancers.
Cancer screening is an attempt to detect unsuspected cancers in an asymptomatic population.
Cancer involves both "uncontrolled growth" and "invasion," and sometimes "metastasis," whereas a benign neoplasm or benign tumor is self-limited, and does not invade or metastasize.
The use of surgery to treat cancer had poor results due to problems with hygiene.
The vaccine protects against four HPV types, which together cause 70% of cervical cancers and 90% of genital warts.
Local organizations may offer a variety of practical and support services to people with cancer.
Some cancers can be caused by infection, from viruses, bacteria, and parasites.
The controversy arises when it is not clear if the benefits of screening outweigh the risks of follow-up diagnostic tests and cancer treatments.
Excessive alcohol consumption is a risk factor in contracting liver cancer, and in combination with tobacco increases the likelihood of developing mouth, larynx, pharynx, and esophageal cancers.
Among well-known cancers are skin cancer, breast cancer (in women), prostate cancer (in men), colon cancer, and lung cancer.
Many cancers may not exhibit any early symptoms, including breast cancer, showing the importance of routine screening.
The increased incidence of malignancies in HIV patients points to the breakdown of immune surveillance as a possible etiology of cancer.
The branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology.
Proposed dietary interventions for primary cancer risk reduction generally gain support from epidemiological association studies.
Studies have shown that immigrants develop the risk of their new country, often within one generation, suggesting a substantial link between diet and cancer.
Benign tumors (which are not cancers) are named using -oma as a suffix with the organ name as the root.
HIV is associated with a number of malignancies, including Kaposi's sarcoma, non-Hodgkin's lymphoma, and HPV-associated malignancies such as anal cancer and cervical cancer.
Immunotherapy uses substances produced the body's own immune system to destroy cancer cells, such as the use of interferons nd interleukins, and monoclonal antibodies.
The malignant versions do involve the invasion of surrounding tissues and perhaps the spreading to other parts of the body; thus, a malignant tumor or malignant neoplasm is cancer.
Screening for breast cancer with mammograms has been shown to reduce the average stage of diagnosis of breast cancer in a population.
Use of medical imaging to search for cancer in people without clear symptoms is similarly marred with problems.
The width of the free margin depends on the type of the cancer, the method of removal (CCPDMA, Mohs surgery, POMA, etc.).
Working with dye, rubber, and gas has been linked to a higher likelihood of getting cancer of the bladder, while lung and skin cancer is linked to smelters, gold mining, and working with arsenic.
Genetic abnormalities found in cancer typically affect two general classes of genes.
The vast majority of cancer risk factors are environmental or lifestyle-related, leading to the claim that cancer is a largely preventable disease.
Tumor suppressor genes are genes that inhibit cell division, survival, or other properties of cancer cells.
The terms cancer and tumor are not synonymous.
Colorectal cancer can be detected through fecal occult blood testing and colonoscopy, which reduces both colon cancer incidence and mortality, presumably through the detection and removal of pre-malignant polyps.
Substances that cause DNA mutations are known as mutagens, and mutagens that cause cancers are known as carcinogens.
Unfortunately, some cancers also use the -oma suffix, examples being melanoma and seminoma.
Cancer pathogenesis is traceable back to DNA mutations that impact cell growth and metastasis.
Among screening tests recommended by the American Cancer Society are mammography for breast cancer, Pap smear for cervical cancer, sigmoidoscopy for colorectal cancer, and the PSA test for prostate cancer.
Sources of ionizing radiation, such as radon gas, x rays, and sunlight, can cause cancer, with about one to two percent of all cancer deaths linked to radiation.
Overall, about one percent of cancer deaths are estimated to be linked to air, water, and land pollution.
Millions of workers run the risk of developing cancers such as lung cancer and mesothelioma from inhaling asbestos fibers and tobacco smoke, or leukemia from exposure to benzene at their workplaces.
Certain foods are believed to protect against various cancers.
Over the past 50 years, great efforts have been spent on gathering data across medical practice, hospital, provincial, state, and even country boundaries to study the interdependence of environmental and cultural factors on cancer incidence.
Cancer prevention, which is defined as active measures to decrease the incidence of cancer, can have considerable success.
The American Cancer Society reports that over one-third (35 percent) of all cancer deaths in the United States are related to diet and nutrition.
Vitamin D. Low levels of vitamin D is correlated with increased cancer risk.
None of these leads to a definitive diagnosis, which usually requires the opinion of a pathologist, a type of physician (medical doctor) who specializes in the diagnosis of cancer and other diseases.
Several sexual and reproductive behaviors correlated with increased risk of cancer.
Hormone therapy is used to block the product of hormones that may increase the growth of certain cancers, like breast and prostate cancer.
Prostate cancer treatment may cause incontinence (inability to control urine flow) and erectile dysfunction.
People with suspected cancer are investigated via a complete medical history and with medical tests.
Liver cirrhosis, whether from chronic viral hepatitis infection or alcoholism, is associated with the development of liver cancer, and the combination of cirrhosis and viral hepatitis presents the highest risk of liver cancer development.
Industrial waste pollution is linked to cancer and there may be a small increased risk of cancer form chlorination of water.
The improved understanding of molecular biology and cellular biology due to cancer research has led to a number of new, effective treatments for cancer since President Nixon declared "War on Cancer" in 1971.
The oldest known description and surgical treatment of cancer can be found in the Edwin Smith Papyrus, a preserved medical document from ancient Egypt that traces to about the sixteenth to seventeenth century B.C.E.
Other possible symptoms of breast cancer include:Swelling of all or part of a breast (even if no distinct lump is felt)Skin irritation or dimpling (sometimes looking like an orange peel)Breast or nipple pain.Nipple retraction (turning inward)Redness, scaliness, or thickening of the nipple or breast skin.More items...
The average 5-year survival rate for people with breast cancer is 90%. The average 10-year survival rate is 83%. If the cancer is located only in the breast, the 5-year relative survival rate of people with breast cancer is 99%. Sixty-one percent (61%) of cases are diagnosed at this stage.
Women with certain risk factors are more likely than others to develop breast cancer. A risk factor is something that may increase the chance of getting a disease. Some risk factors (such as drinking alcohol) can be avoided. But most risk factors (such as having a family history of breast cancer) can't be avoided.
It is the excessive cell growth that causes cancer. Breast cancer usually starts in the inner lining of milk ducts or the lobules that supply them with milk. From there, it can spread to other parts of the body.Nov 27, 2017
Signs of Inflammatory Breast Cancer. This rare, fast-growing type rarely causes a distinct lump. Instead, breast skin can become thick, red, and look pitted, like an orange peel. The area might also feel warm or tender and have small bumps that look like a rash.Oct 15, 2017
The following are steps you can take to lower your risk:Limit alcohol. The more alcohol you drink, the greater your risk of developing breast cancer. ... Don't smoke. ... Control your weight. ... Be physically active. ... Breast-feed. ... Limit dose and duration of hormone therapy. ... Avoid exposure to radiation and environmental pollution.
The following foods are considered part of a healthful diet in general, and they may help to prevent the development or progression of breast cancer:a wide variety of colorful fruits and vegetables.foods rich in fiber, such as whole grains, beans, and legumes.low-fat milk and dairy products.soybean-based products.More items...
Breast Massages May Prevent Cancer, Study Says. An erotic massage is both healthy and sexy — making it a win for you and your partner. A revelation in science suggests that a simple squeeze of the breasts may help prevent malignant cells from triggering breast cancer.Jun 7, 2013
Cancer is the uncontrolled growth of abnormal cells in the body. ... Cancer develops when the body's normal control mechanism stops working. Old cells do not die and cells grow out of control, forming new, abnormal cells. These extra cells may form a mass of tissue, called a tumor.Nov 1, 2013
The following symptoms may also indicate the presence of some form of cancer:Coughing-up blood.Persistent headaches.Unexplained loss of weight or appetite.Chronic pain in bones.Persistent fatigue, nausea, or vomiting.Persistent low-grade fever, either constant or intermittent.Repeated instances of infection.
Gene mutations that occur after birth. Most gene mutations occur after you're born and aren't inherited. A number of forces can cause gene mutations, such as smoking, radiation, viruses, cancer-causing chemicals (carcinogens), obesity, hormones, chronic inflammation and a lack of exercise.May 23, 2015
They are very emotional and sensitive, and care deeply about matters of the family and their home. Cancer is sympathetic and attached to people they keep close. Those born with their Sun in Cancer are very loyal and able to empathize with other people's pain and suffering.
Cancer, the fourth sign of the zodiac, is all about home. Those born under this sign are 'roots' kinds of people, and take great pleasure in the comforts of home and family. Cancers are maternal, domestic and love to nurture others.Sep 25, 2017
The Cancer horoscope symbol is the Crab. The Crab sign symbol is usually depicted as a very simple graphic meant to resemble a sideways “69” to represent crab claws or a woman's breast. Cancer dates typically fall from June 21 to July 22. ... Cancer is ruled by the moon, which has a symbol of its own.
Cancer & Aries. The impatience of Aries and the slow, emotional serenade of Cancer don't go well together. ... Cancer & Taurus. Taurus and Cancer are the seed of a family, both of them true believers in intimacy. ... Cancer & Gemini. ... Cancer & Cancer. ... Cancer & Leo. ... Cancer & Virgo. ... Cancer & Libra. ... Cancer & Scorpio.More items...
Compatibility: Cancer is most compatible with other water signs: Scorpio, Pisces, and other Cancers. Earth signs, like Taurus, Virgo, and Capricorn, are also very compatible. Incompatibility: Fire signs, like Aries, Leo, and Sagittarius, do not work well; neither do air signs Aquarius, Gemini, and Libra.Jun 16, 2016
The most compatible signs with Cancer are generally considered to be Taurus, Virgo, Scorpio and Pisces. The least compatible signs with Cancer are generally considered to be Aries and Libra. Comparing sun signs can give a good general idea of compatibility.
On average, respondents in this group considered that smoking can cause cancer only if one smokes at least 19.4 cigarettes per day (for an average reported consumption of 5.5 cigarettes per day), and that cancer risk becomes high for a smoking duration of 16.9 years or more (reported average duration: 16.7).
A: While it's true that microwave ovens emit tiny amounts of radiation, studies have shown that they're not nearly enough to cause cancer. A microwave could cause other injuries (like burns or cataracts), but only if it's been damaged and starts leaking large amounts of radiation—an unlikely occurrence.
Learn what it means to be born on the Gemini-Cancer cusp. If you were born on the Gemini-Cancer cusp, from about June 17 to June 23, you're a magical individual! The energies of Gemini and Cancer combine to create truly inspirational human beings -- both lighthearted and fun, but also caring and devoted.Nov 17, 2017
Statistics on the outlook for a certain type and stage of cancer are often given as 5-year survival rates, but many people live longer – often much longer – than 5 years. The 5-year survival rate is the percentage of people who live at least 5 years after being diagnosed with cancer.May 16, 2016
These cancers can't be removed completely by surgery. As with other stages of lung cancer, treatment depends on the patient's overall health. If you are in fairly good health you may be helped by chemotherapy (chemo) combined with radiation therapy. Some people can even be cured with this treatment.Jun 23, 2017
Lung cancers, also known as bronchogenic carcinomas ("carcinoma" is another term for cancer), are broadly classified into two types: small cell lung cancers (SCLC) and non-small cell lung cancers (NSCLC). This classification is based upon the microscopic appearance of the tumor cells.Jan 18, 2016
Lung cancer starts when abnormal cells grow out of control in the lung. They can invade nearby tissues and form tumours. Lung cancer can start anywhere in the lungs and affect any part of the respiratory system. The cancer cells can spread, or metastasize, to the lymph nodes and other parts of the body.
Lung cancer is the uncontrolled growth of abnormal cells in one or both lungs. ... As they grow, the abnormal cells can form tumors and interfere with the functioning of the lung, which provides oxygen to the body via the blood.
Since lung cancer tends to spread or metastasize very early after it forms, it is a very life-threatening cancer and one of the most difficult cancers to treat. ... For example, if prostate cancer spreads via the bloodstream to the lungs, it is metastatic prostate cancer in the lung and is not lung cancer.
If you go to your doctor when you first notice symptoms, your cancer might be diagnosed at an earlier stage, when treatment is more likely to be effective. The most common symptoms of lung cancer are: A cough that does not go away or gets worse. ... Chest pain that is often worse with deep breathing, coughing, or laughing.Feb 22, 2016
When NSCLC has spread outside of the lungs, it can be difficult to treat. The 5-year survival rate for stage IV NSCLC is around 1%. Each year, tens of thousands of people are cured of NSCLC in the United States. And, some patients with advanced lung cancer can live many years after diagnosis.
Small Cell Lung Cancer - The overall 5-year survival rate for both stages of small cell lung cancer (limited stage plus extensive stage) is only about 6 percent. Without treatment, the average life expectancy for extensive disease is 2 to 4 months, and with treatment is 6 to 12 months.
As noted above, when surgery is done at any early stage, has not spread to lymph nodes or blood vessels, doctors may sometimes use the word cure. Surgery may be performed for those with stage 1, stage 2 and stage 3A non-small cell lung cancer.Jan 3, 2018
Cancer (constellation) Best visible at 21:00 (9 p.m.) during the month of March. Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as one.
Under the tropical zodiac, the Sun transits this area on average between June 22 and July 22, and under the sidereal zodiac, the Sun transits this area between approximately July 16 and August 15. In astrology, Cancer is the cardinal sign of the Water trigon, which is made up of Cancer, Pisces, and Scorpio.
When Aries and Cancer come together in a love affair, it's a case of opposites attracting. Aries is rash and brash while Cancer is sensitive and emotional. Aries can certainly be emotional — in a fiery, impetuous way that can completely overwhelm Cancer.
Having asthma doesn't up your odds of getting lung cancer, but if symptoms aren't controlled, it may eventually develop into chronic obstructive pulmonary disease, or COPD. COPD is basically an umbrella term used to describe treatable but irreversible lung conditions such as emphysema and chronic bronchitis.
When white blood cells increase in number, we have a condition called leukocytosis. Causes of leukocytosis include infection, such as tuberculosis or pertussis. It can also be caused by certain cancers and inflammatory conditions. Any of the five types of leukocytes can increase in number.