Tobacco smoking is the main known contributor to urinary bladder cancer; in most populations, smoking is associated with over half of bladder cancer cases in men and one-third of cases among women, however these proportions have reduced over recent years since there are fewer smokers in Europe and North America. There is an almost linear relationship between smoking duration (in years), pack years and bladder cancer risk. A risk plateau at smoking about 15 cigarettes a day can be observed (meaning that those who smoke 15 cigarettes a day are approximately at the same risk as those smoking 30 cigarettes a day). Quitting smoking reduces the risk, however former smokers will most likely always be at a higher risk of bladder cancer compared to never smokers. Passive smoking has not been proven to be involved.

Thirty percent of bladder tumors probably result from occupational exposure in the workplace to carcinogens such as benzidine. 2-Naphthylamine, which is found in cigarette smoke, has also been shown to increase bladder cancer risk. Occupations at risk are bus drivers, rubber workers, motor mechanics, leather (including shoe) workers, blacksmiths, machine setters, and mechanics. Hairdressers are thought to be at risk as well because of their frequent exposure to permanent hair dyes.

In addition to these major risk factors there are also numerous other modifiable factors that are less strongly (i.e. 10–20% risk increase) associated with bladder cancer, for example, obesity. Although these could be considered as minor effects, risk reduction in the general population could still be achieved by reducing the prevalence of a number of smaller risk factor together.

It has been suggested that mutations at HRAS, KRAS2, RB1, and FGFR3 may be associated in some cases.

Compared to other breeds of dog, Scottish terriers have a much increased risk of developing transitional cell carcinoma.

A 2008 study commissioned by the World Health Organisation concluded that "specific fruit and vegetables may act to reduce the risk of bladder cancer." Fruit and yellow-orange vegetables, particularly carrots and those containing selenium, are probably associated with a moderately reduced risk of bladder cancer. Citrus fruits and cruciferous vegetables were also identified as having a possibly protective effect. However an analysis of 47,909 men in the Health Professionals Follow-Up Study showed little correlation between cancer reduction and high consumption of fruits and vegetables overall, or yellow or green leafy vegetables specifically, compared to the statistically significant reduction among those men who consumed large amounts of cruciferous vegetables.

In a 10-year study involving almost 49,000 men, researchers found that men who drank at least 1,44 L of water (around 6 cups) per day had a significantly reduced incidence of bladder cancer when compared with men who drank less. It was also found that: "the risk of bladder cancer decreased by 7% for every 240 mL of fluid added". The authors proposed that bladder cancer might partly be caused by the bladder directly contacting carcinogens that are excreted in urine, although this has not yet been confirmed in other studies.

The two major risk factors for esophageal squamous-cell carcinoma are tobacco (smoking or chewing) and alcohol. The combination of tobacco and alcohol has a strong synergistic effect. Some data suggest that about half of all cases are due to tobacco and about one-third to alcohol, while over three-quarters of the cases in men are due to the combination of smoking and heavy drinking. Risks associated with alcohol appear to be linked to its aldehyde metabolite and to mutations in certain related enzymes. Such metabolic variants are relatively common in Asia.

Other relevant risk factors include regular consumption of very hot drinks (over 65 °C)(149 Fahrenheit) and ingestion of caustic substances. High levels of dietary exposure to nitrosamines (chemical compounds found both in tobacco smoke and certain foodstuffs) also appear to be a relevant risk factor. Unfavorable dietary patterns seem to involve exposure to nitrosamines through processed and barbecued meats, pickled vegetables, etc., and a low intake of fresh foods. Other associated factors include nutritional deficiencies, low socioeconomic status, and poor oral hygiene. Chewing betel nut (areca) is an important risk factor in Asia.

Physical trauma may increase the risk. This may include the drinking of very hot drinks.

Cancer of the stomach, also called gastric cancer, is the fourth-most-common type of cancer and the second-highest cause of cancer death globally. Eastern Asia (China, Japan, Korea, Mongolia) is a high-risk area for gastric cancer, and North America, Australia, New Zealand and western and northern Africa are areas with low risk. The most common type of gastric cancer is adenocarcinoma, which causes about 750,000 deaths each year. Important factors that may contribute to the development of gastric cancer include diet, smoking and alcohol consumption, genetic aspects (including a number of heritable syndromes) and infections (for example, "Helicobacter pylori" or Epstein-Barr virus) and pernicious anemia. Chemotherapy improves survival compared to best supportive care, however the optimal regimen is unclear.

Risk factors for pancreatic adenocarcinoma include:

- Age, gender, and ethnicity; the risk of developing pancreatic cancer increases with age. Most cases occur after age 65, while cases before age 40 are uncommon. The disease is slightly more common in men than women, and in the United States is over 1.5 times more common in African Americans, though incidence in Africa is low.

- Cigarette smoking is the best-established avoidable risk factor for pancreatic cancer, approximately doubling risk among long-term smokers, the risk increasing with the number of cigarettes smoked and the years of smoking. The risk declines slowly after smoking cessation, taking some 20 years to return to almost that of non-smokers.

- Obesity; a BMI greater than 35 increases relative risk by about half.

- Family history; 5–10% of pancreatic cancer cases have an inherited component, where people have a family history of pancreatic cancer. The risk escalates greatly if more than one first-degree relative had the disease, and more modestly if they developed it before the age of 50. Most of the genes involved have not been identified. Hereditary pancreatitis gives a greatly increased lifetime risk of pancreatic cancer of 30–40% to the age of 70. Screening for early pancreatic cancer may be offered to individuals with hereditary pancreatitis on a research basis. Some people may choose to have their pancreas surgically removed to prevent cancer developing in the future.

- Chronic pancreatitis appears to almost triple risk, and as with diabetes, new-onset pancreatitis may be a symptom of a tumor. The risk of pancreatic cancer in individuals with familial pancreatitis is particularly high.

- Diabetes mellitus is a risk factor for pancreatic cancer and (as noted in the Signs and symptoms section) new-onset diabetes may also be an early sign of the disease. People who have been diagnosed with Type 2 diabetes for longer than ten years may have a 50% increased risk, as compared with non-diabetics.

- Specific types of food (as distinct from obesity) have not been clearly shown to increase the risk of pancreatic cancer. Dietary factors for which there is some evidence of slightly increased risk include processed meat, red meat, and meat cooked at very high temperatures (e.g. by frying, broiling or barbecuing).

People with Barrett's esophagus (a change in the cells lining the lower esophagus) are at much higher risk, and may receive regular endoscopic screening for the early signs of cancer. Because the benefit of screening for adenocarcinoma in people without symptoms is unclear, it is not recommended in the United States. Some areas of the world with high rates of squamous-carcinoma have screening programs.

The median overall survival rate is about 50% in 5 years. Worse prognostic factors include the presence of residual tumor at the margin of the resection specimen (R+), invasion of the peritoneum and metastatic disease.

Drinking alcohol excessively is a major cause of chronic pancreatitis, which in turn predisposes to pancreatic cancer. However, considerable research has failed to firmly establish alcohol consumption as a direct risk factor for pancreatic cancer. Overall, the association is consistently weak and the majority of studies have found no association, with smoking a strong confounding factor. The evidence is stronger for a link with heavy drinking, of at least six drinks per day.

Pancreatic cancer is the fifth-most-common cause of cancer deaths in the United States, and the seventh most common in Europe. In 2008, globally there were 280,000 new cases of pancreatic cancer reported and 265,000 deaths. These cancers are classified as endocrine or nonendocrine tumors. The most common is ductal adenocarcinoma. The most significant risk factors for pancreatic cancer are advanced age (over 60) and smoking. Chronic pancreatitis, diabetes or other conditions may also be involved in their development. Early pancreatic cancer does not tend to result in any symptom, but when a tumor is advanced, a patient may experience severe pain in the upper abdomen, possibly radiating to the back. Another symptom might be jaundice, a yellowing of the skin and eyes.

Pancreatic cancer has a poor prognosis, with a five-year survival rate of less than 5%. By the time the cancer is diagnosed, it is usually at an advanced, inoperable stage. Only one in about fifteen to twenty patients is curative surgery attempted. Pancreatic cancer tends to be aggressive, and it resists radiotherapy and chemotherapy.

Because most bladder cancers are invasive into the bladder wall, surgical removal is usually not possible. The majority of transitional cell carcinomas are treated with either traditional chemotherapy or nonsteroidal anti-inflammatory drugs.

Primary signet ring cell carcinoma of the colon and rectum (PSRCCR) is rare, with a reported incidence of less than 1 percent. It has a poor prognosis because symptoms often develop late and it is usually diagnosed at an advanced stage. Five-year survival rates in previous studies ranged from nine to 30 percent. Average survival was between 20 and 45 months. It tends to affect younger adults with higher likelihood of lymphovascular invasion. It is worth noting that the overall survival rate of patients with SRCC was significantly poorer than that of patients with mucinous or poorly differentiated adenocarcinoma.

In advanced gastric cancers, the prognosis for patients with the SRCCs was significantly worse than for the other histological types, which can be explained by the finding that advanced SRCC gastric cancers have a larger tumor size, more lymph node metastasis, a deeper invasive depth and more Borrmann type 4 lesions than other types.

Primary signet-ring cell carcinoma of the urinary bladder is extremely rare and patient survival is very poor and occurs mainly in men ages 38 to 83. However, one such patient treated with a radical cystectomy followed by combined S-1 and Cisplatin adjuvant chemotherapy did demonstrate promising long-term survival of 90 months.

Clear-cell adenocarcinoma is a type of adenocarcinoma that shows clear cells.

Types include:

- Clear-cell adenocarcinoma of the vagina

- Clear-cell ovarian carcinoma

- Uterine clear-cell carcinoma

- Clear-cell adenocarcinoma of the lung (which is a type of Clear-cell carcinoma of the lung)

See also:

- Clear-cell squamous cell carcinoma of the lung

When associated with the lung, it is typically a centrally located large cell cancer (non-small cell lung cancer or NSCLC). It often has a paraneoplastic syndrome causing ectopic production of parathyroid hormone-related protein (PTHrP), resulting in hypercalcemia, however paraneoplastic syndrome is more commonly associated with small cell lung cancer.

It is primarily due to smoking.

Urachal cancer is a very rare type of cancer arising from the urachus or its remnants. The disease might arise from metaplasic glandular epithelium or embryonic epithelial remnants originating from the cloaca region.

It occurs in roughly about one person per 1 million people per year varying on the geographical region. Men are affected slightly more often than women mostly in the 5th decade of life but the disease can occur in also in other age groups.

It can involve the urinary bladder, but is not bladder cancer in the usual sense. Urachal cancer can occur at any site along the urachal tract.

Urachal cancer was mentioned by Hue and Jacquin in 1863 followed by an elaborate work by T. Cullen in 1916 about diseases of the umbilicus, while C. Begg further characterized urachal cancer in the 1930s. Detailed diagnostic and staging schemes were proposed by Sheldon et al in 1984, which remain widely used today.

Human papillomavirus infection (HPV) has been associated with SCC of the oropharynx, lung, fingers and anogenital region.

Hepatoid tumor or hepatoid [adeno]carcinoma are terms for a number of uncommon or rare neoplasms in humans, named for a visual resemblance of the cells under the microscope to those of hepatocellular carcinoma, the most common form of liver cancer. They can arise in several parts of the body, and thus form sub-types of diseases such as stomach cancer and pancreatic cancer. The WHO defines "Hepatoid carcinoma" as "An adenocarcinoma with morphologic characteristics similar to hepatocellular carcinoma , arising from an anatomic site other than the liver".

In dogs it may refer to a Perianal gland tumor, based on a similar resemblance to healthy liver cells.

The overall incidence is 0.5 to 1 cases per 100,000 people per year. It is slightly more common in women than men (male:female ratio = 9:11). The median age at presentation is typically about 50 years with a range of 20–25 years.

Oesophagogastric junctional adenocarcinoma is a cancer of the lower part of the oesophagus, often linked to a Barrett's oesophagus.

The incidence of oesophagogastric junctional adenocarcinoma is rising rapidly in western countries, in contrast to the declining frequency of distal gastric adenocarcinoma. Treatment options for adenocarcinomas involving the oesophagogastric junction are limited and the overall prognosis is extremely poor.

MCACL has a much more favorable prognosis than most other forms of adenocarcinoma and most other NSCLC's. Cases have been documented of continued growth of these lesions over a period of 10 years without symptoms or metastasis. The overall mortality rate appears to be somewhere in the vicinity of 18% to 27%, depending on the criteria that are used to define this entity.

Taken as a class, long-term survival rates in BAC tend to be higher than those of other forms of NSCLC. BAC generally carries a better prognosis than other forms of NSCLC, which can be partially attributed to localized presentation of the disease. Though other factors might play a role. Prognosis of BAC depends upon the histological subtype and extent at presentation but are generally same as other NSCLC.

Recent research has made it clear that nonmucinous and mucinous BACs are very different types of lung cancer. Mucinous BAC is much more likely to present with multiple unilateral tumors and/or in a unilateral or bilateral pneumonic form than nonmucinous BAC. The overall prognosis for patients with mucinous BAC is significantly worse than patients with nonmucinous BAC.

Although data are scarce, some studies suggest that survival rates are even lower in the mixed mucinous/non-mucinous variant than in the monophasic forms.

In non-mucinous BAC, neither Clara cell nor Type II pneumocyte differentiation appears to affect survival or prognosis.

Accurate incidence statistics on MCACL are unavailable. It is a very rare tumor, with only a few dozen cases reported in the literature to date.

In the few cases described in the literature to date, the male-to-female ratio is approximately unity, and right lung lesions occurred twice as commonly as left lung lesions. Approximately 2/3 of cases have been associated with tobacco smoking. Cases have been reported in patients as young as 29.

When BAC recurs after surgery, the recurrences are local in about three-quarters of cases, a rate higher than other forms of NSCLC, which tends to recur distantly.

OGJ adenocarcinoma is a highly mutated and heterogeneous disease. Microsatellite instability (MSI) can be observed and coincides with an elevated number of somatic mutations. Potentially actionable coding mutations have been identified in 67 genes, including those in CR2, HGF, FGFR4 and ESRRB. Numerous genes harbouring somatic coding mutations and copy number changes in the microsatellite stable (MSS) OGJA are also known to be altered with similar predicted functional consequence in other tumour types. TP53, SYNE1, and ARID1A are among the most frequently mutated genes.