Researchers in Ireland found that curcumin can kill esophageal cancer cells. Curcumin is the compound that gives turmeric its characteristic yellow color. The cancer cells used in this investigation were grown in vitro (in glass/petri dishes). The scientists also found that curcumin started killing the malignant cells within 24 hours, while simultaneously digesting themselves.
Dr. O'Sullivan, first author and researcher, had been looking for novel ways of killing resistant esophageal cancer cells. When she began using curcumin, she noted that the cells started dying using a signalling system that did not involve apoptosis or cell suicide, which is the most usual route by which faulty cells die. They concluded that the curcumin killed the tumorigenic cells through another biochemical path.
Rationale for the Investigation
The team launched this research in response to the rising incidence of esophageal cancer. On a global basis, esophageal cancer ranks 6th most common tumor disease. It is characterized by rapid development and fatal prognosis in most cases. The occurrence of this disease increases with age with the highest incidence in the 50-70 year age group. It is diagnosed more frequently in males than females with an approximate ratio of 3 -5:1.
The most frequent histological type is squamous cell carcinoma (malginancy of flat cells like floor tiles). The prognosis of esophageal cancer is generally unfavorable even when the tumor is surgically removed at its early stages and operable stages. The 5-year survival rate is less than 5%.
Causes of Esophageal Cancer
Esophageal cancer is often induced by chronic irritants and genetic inheritance. Elements that include lifestyle and environmental criteria are as follows:
- Smoking. Studies showing people smoking 35 or more cigarettes per day showed the highest esophageal cancer risk.
- Chewing tobacco. In regions where chewing tobacco is popular (Iran, Afghanistan, middle Asia, and China), the incidence of esophageal cancer has been high compared with other areas where the habit is less practiced by the population.
- Ingestion of very hot beverages or food. In some Central American countries where drinking very hot "mate" is practiced, high rates of esophageal and mouth cancers have been noted. Mate is a tea prepared from Ilex paraguayensis.
- Consumption of pickled vegetables. Pickled vegetables are associated with nitroso compounds and mycotoxins. These molecules represent risk factors for oral cancers.
- Infectious agents. Some studies have found the presence of human papilloma virus (HPV) in 20-70% of patients with esophageal cancer, while other trials did not confirm these findings. Fungi-contaminated wheat and maize are suspected to be associated with esophageal carcinoma.
- Physical and chemical factors. Chronic injuries, ionizing radiation, asbestos contamination of food by silica fibers, and traumatic burn to the esophagus results in scar formation and constriction of the esophagus.
- Occupational risk factors. Labourers exposed to combustion and diesel pollutants are at higher risk for oral cancers. Some of these persons include chimney sweeps, persons who work with oil refining, etc. Long-term exposure to berylium also increases the risk of developing esophageal cancer. Oral cancer has also been observed among labourers/farmers working with pesticides.
- Heredity. Tylosis is a genetic disorder characterized by the thickening of the palms and soles, white patches in the mouth predisposes a person to esphageal cancer. Plummer-Vinson Syndrome, a long-term iron deficiency anemia afflicts those with the disorder by making swallowing difficult. It is due to the development of web-like thin growths of tissue that blocks the food tube. Barrett's esophagus is another condition that may induce esophageal cancer. In Barrett's esophagus, the esophageal lining is damaged by stomach acids.
- While genetic predisposition to esophageal cancer exists, its relative risk is smaller (2.69) in comparison with lifestyle related risk factors. Prevention of esophageal cancer should be used on early detection and surveillance of precancerous tissues, particularly in Barrett's esophagus. Interventions should be focused on modification of changeable risk elements including tobacco use, alcohol abuse, ingestion of known carcinogenic foods, and other factors.
References:
McKenna S et al. "Curcumin induces apoptosis independent death in esophageal cancer cells" British J Cancer October 28, 2009
Yao PF et al. "Evidence of human papilloma virus infection and its epidemiology in esophageal squamous cell carcinoma: World J Gasteroenterol 2006;12(9):1352-5
Akbai MR et al. " Familial risks of esophageal cancer among the Turkmen population of the Caspian littoral of Iran" Int J Cancer 2006;119(5):1047-51
Huang HC et al. " Association between diet and esophageal cancer in Taiwan" J Gastroenterol Hepatol 2004;19(6)632-7
Castellsague X et al. "Independent and joint effects of tobacco smoking and alcohol drinking on the risk of esophageal cancer in males and females" Int J Cancer 1999;82(5):65-64
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