By Marc Sorenson, EdD Sunlight Institute
Those of us that understand the importance on regular sun exposure on human health were not surprised by the most recent research by Dr. Pelle Lindqvist and colleagues. It showed that women who had active sun-exposure habits lived longer than those who did not.[1] Over a 20-year period, the study demonstrated that compared to the highest sun-exposure group, life expectancy of sun avoiders was reduced significantly. Much of the reduction in death among the sun-exposed group was due to a lessened risk of cardiovascular disease and non-cancer, non-cardiovascular death. The risk of skin cancer was slightly increased among the sun exposed group, primarily because they lived longer and had more time to contract cancer.
Perhaps the most impressive statement to come out of the research was this: “Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking.”
This newest research is just one of several important contributions by Lindqvist and his group. Other assessments of the 20-year study revealed that the subjects who avoided sun exposure were twice as likely to die of any cause compared to those who had the highest sun exposure, and the researchers made this statement: “In both models the summary sun exposure variables showed a ‘dose-dependent’ inverse relation between sun exposure and all-cause death.”[2]
The research also showed that women with “normal” sun exposure habits were not at significantly increased risk of either melanoma or melanoma-related death. The publication seemed to give vitamin D most of the credit for increased life spans among those who had high sun exposures, but also mentioned the possibility that nitric-oxide production by sun-exposed skin may have been a factor.
If avoiding the sun is as dangerous as smoking cigarettes, why do many dermatologists still try to frighten us to death about soaking up some rays? Will they never learn?
[1] Lindqvist PG, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. 2016 Mar 16. doi: 10.1111/joim.12496. [Epub ahead of print].
[2] Pelle G. Lindqvist, Elisabeth Epstein, Mona Landin-Olsson, Christian Ingvar, Kari Nielsen, Magnus Stenbeck & Håkan Olsson. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86.
By Marc Sorenson, EdD Sunlight Institute…
Leukemia is a cancer of the bone marrow that prevents the normal manufacture of red blood cells, white blood cells and platelets. It can lead to infection, impaired blood clotting and anemia. The good news is that embracing the sun may have a profoundly protective effect against this deadly disease.
Consider this research by Dr. Timo Tomonen and his colleagues that showed a very close relationship between sun deprivation and acute myeloid leukemia.[1] The researchers stated that “During the light season, the incidence decreased by 58% (95% confidence interval, 16–79%) per 1,000 kJ/m2/d increase of solar radiation.” In Finland, It has also been shown that deficiency of sunlight (and perhaps cold weather) was associated with excessive diagnoses when compared to diagnoses in in the sunlit, warm season. Other research has indicated that sun exposure during mothers’ pregnancies reduced the risk of leukemia and other cancers in their children.[2]
Finally, in a laboratory study using UVA irradiation of leukemia cells, it was found that such radiation caused rapid apoptosis (natural cell death) in the exposed cells.[3] UVA, of course, is the major ultraviolet component of the solar radiation that reaches the earth. UVA also has been shown to cause a marked decline in the proliferation of leukemia cells.[4] Proliferation is the process of rapid growth and multiplication of cancer cells. So it appears that sun exposure has two more positive attributes for preventing cancers: it has the ability to hasten the death of cancer cells and to retard the tendency of cancer cells to grow and multiply out-of-control. It is also interesting to note, although the researchers did not mention it, that UVA exposure does not cause the production of vitamin D, which means that some other mechanism of sun exposure was responsible for the positive results. Vitamin D is a wonderful photoproduct of sun exposure, but positive benefits of other photoproducts are available. When we substitute vitamin D supplements for sun exposure we may make a critical mistake and increase our risk of leukemia and other diseases. Nothing is a match for habitual, safe sun exposure, but sun lamps would be a close second.
The sun is a natural protector against leukemia. What more need we say?
[1] Timo Timonen, Simo Näyhä, Tapani Koskela, Eero Pukkala. Are sun deprivation and influenza epidemics associated with the onset of acute leukemia? Haematologica 2007; 92 (11):1553-56.
[2] Christina Lombardi, Julia E. Heck, Myles Cockburn, and Beate Ritz. Solar UV Radiation and Cancer in Young Children. Cancer Epidemiol Biomarkers Prev 2013;22:1118-1128.
[3] Zhuang S, Kochevar IE. Ultraviolet A radiation induces rapid apoptosis of human leukemia cells by Fas ligand-independent activation of the Fas death pathways. Photochem Photobiol. 2003 Jul;78(1):61-7.
[4] Leszczynski D, Fagerholm S, Leszczynski K. The effects of the broadband UVA radiation on myeloid leukemia cells: the possible role of protein kinase C in mediation of UVA-induced effects. Photochem Photobiol. 1996 Dec;64(6):936-42.
By Marc Sorenson, EdD. Sunlight Institute
Part of our brain function is influenced by a naturally produced protein called Brain-Derived Neurotropic Factor (BDNF), part of a cascade of proteins that promotes neuron growth and prevents neuron death.[1] Research shows that BDNF has an influence on processes and behaviors such as depression and brain plasticity and has a seasonal variation in concentration that correlates with the amount of ambient sun;[2] BDNF increases in the spring and summer and decreases in fall and winter. The authors of this research summed up their findings thusly: “This finding is important for our understanding of those factors that regulate BDNF expression and may provide novel avenues to understand seasonal dependent changes in behavior and illness such as depression.”
Correct levels of BDNF, however, have many other important and positive effects in the body,[3] including promoting of long-term memory, regulation of mood and perception of pain, reduction of Alzheimer’s disease and Huntington’s disease, and control of epilepsy, depression, anxiety, bipolar disorders, schizophrenia and addiction. In addition, it has positive effects on type-two diabetes, cardiovascular disease and colorectal cancer.
BDNF has been shown to increase significantly after bright light exposure,[4] and in what I would consider to be a remarkably important study, both light exposure and treadmill exercise increased the expression of BDNF in rats,[5] or as the researchers showed, exercise and/or bright light promoted neurogenesis (new nerve cell growth) in the adult rat brain. How important is this finding for adults who are worried about cognitive decline? We are actually seeing an example of new brain cells being built by bright light and exercise. But the researchers were not through with their recommendations. They stated this in their summary: “In view of these findings, we propose that moderate exercise or exposure to sun during childhood can be beneficial for neural development.”
Other research has also indicated that physical activity is positively associated with BDNF.[6]
Add one more natural chemical that is inversely associated with depression and directly associated with sun exposure. We now have vitamin D, serotonin, endorphins, dopamine and BDNF.
Want to maintain your IQ and other brain functions? Would you rather not take the chance of suffering from Alzheimer’s? Embrace the sun, and move your body! Be careful not to burn. And remember that the use of sunscreens may negate many of the sun’s wholesome effects.
[1] http://scicurious.scientopia.org/2010/12/13/bdnf-and-depression/
[2] Molendijk ML, Haffmans JP, Bus BA, Spinhoven P, Penninx BW, Prickaerts J, Oude Voshaar RC, Elzinga BM. Serum BDNF concentrations show strong seasonal variation and correlations with the amount of ambient sun. PLoS One. 2012;7(11):e48046.
[3] Juzeniene A. Beneficial effects of UV‐radiation unrelated to Vitamin D. Presentation at International Symposium Biological Effects of Light June 11 ‐ 12, 2015 Homborg, Germany.
[4] Tirassa P, Iannitelli A, Sornelli F, Cirulli F, Mazza M, Calza A, Alleva E, Branchi I, Aloe L, Bersani G, Pacitti F. Daily serum and salivary BDNF levels correlate with morning-evening personality type in women and are affected by light therapy. Riv Psichiatr. 2012 Nov-Dec;47(6):527-34.
[5] Kwon SJ, Park J, Park SY, Song KS, Jung ST, Jung SB, Park IR, Choi WS, Kwon SO. Low-intensity treadmill exercise and/or bright light promote neurogenesis in adult rat brain. Neural Regen Res. 2013 Apr 5;8(10):922-9.
[6] Gomes da Silva S, Arida RM. Physical activity and brain development. Expert Rev Neurother. 2015 Aug 9:1-11.
By Marc Sorenson, EdD, Sunlight Institute…
A new investigation from Chinese researchers demonstrates that sun exposure is dramatically protective against Parkinson’s disease (PD).[1] The paper reported a study in which 201 newly diagnosed patients were compared with 199 controls who were free of PD. Data on vitamin D intake, blood vitamin D levels and sun exposure were obtained in both groups by using a self-report questionnaire.
For blood vitamin D levels, those who had the highest levels had a 48% lowered risk of PD; for sun exposure, those receiving the greatest exposure had about 47% reduced risk of PD.
Whereas a significant positive correlation existed between blood levels of vitamin D and sun exposure, vitamin D intake from supplements, food, etc. did not correlate to blood levels of vitamin D.
This is a particularly interesting study in that it demonstrates that vitamin D should be raised by exposure to the sun when possible rather than dietary intake. It appears that dietary intake the amounts most people receive is not effective for raising those levels.
The evidence for a protective effect of sun exposure against PD has been building for some time. In 1988, it was observed that when four northern census regions of the U.S. were compared with three southern regions, death rates for PD were significantly higher in the northern regions,[2] indicating a possible protective effect of sun exposure. Later research corroborated those findings, demonstrating a strong north-south decreasing gradient for PD among whites.[3]
There are several more studies indicative of a positive effect of sun on PD, and these will be included in the book on sunlight that Dr. William Grant and I are writing, and which we hope to have published in May. Stay tuned, and safely embrace the sun!
[1] Juan Wang, Deyu Yang, Yu Yu, Gaohai Shao and Qunbo Wang 2. Vitamin D and Sunlight Exposure in Newly-Diagnosed Parkinson’s Disease. Nutrients 2016;8:142.
[2] Kurtzke JF, Goldberg ID. Parkinsonism death rates by race, sex, and geography. Neurology. 1988 Oct;38(10):1558-61.
[3] Lanska DJ. The geographic distribution of Parkinson’s disease mortality in the United States. J Neurol Sci. 1997 Sep 1;150(1):63-70.
By Marc Sorenson, EdD, Sunlight Institute…
A study from China demonstrates that residents who have the lowest sun exposure also have the highest risk of death.[1] The study obtained overall death rates and incidence rates from cancers per se from a national database during the years from 1998 to 2002) They compared those death rates to the quantity of sun intensity in the areas (263 counties) in which the residents lived.
The results were telling: Overall death risk for all cancers combined, and specifically for cancers of the esophagus, stomach, colon, rectum, liver, lung, breast and bladder were inversely correlated with increasing sun exposure. Lung cancer showed the greatest protection provided by sun exposure, with a 12% decrease in death risk for every 10 mW/(nm m2) increase in UVB irradiance (a measure of intensity of sun exposure).
Incidence rates of several cancers were also inversely correlated to sun exposure, namely cancers of the esophagus, stomach, colon, rectum and cervix. Only nasopharyngeal cancer and cervical cancer increased with sun exposure. The authors suggested the possibility that vitamin D provided the mechanism by which the overall cancer rates were reduced.
Dr. William Grant has confirmed that there are many cancers that correlate to low sun exposure and/or low vitamin D levels,[2] and there are dozens more diseases beyond cancer that have an inverse relationship with sun exposure. Dr. Grant and I will soon release a book that will delve into all of the diseases that sun exposure helps to prevent. Please world, let us back in the sun without making us feel guilty!
[1] Chen W, Clements M, Rahman B, Zhang S, Qiao Y, Armstrong BK. Relationship between cancer mortality/incidence and ambient ultraviolet B irradiance in China. Cancer Causes Control. 2010 Oct;21(10):1701-9.
[2] William B. Grant. Role of solar UVB irradiance and smoking in cancer as inferred from cancer incidence rates by occupation in Nordic countries. Dermato-Endocrinology 4:2, 203–211; April/May/June 2012.
By Marc Sorenson, EdD, Sunlight Institute…
An impressive research paper on colorectal cancer demonstrates that both vitamin D supplementation and ultraviolet-light (UV) exposure are effective in reducing that cancer.[1] To begin the research, mice that are bred to be susceptible to intestinal tumors were put on a vitamin D-deficient diet, which reduced vitamin D levels significantly and spurred the development of non-cancerous tumors. Then, the diseased animals were either supplemented with vitamin D, or exposed to UV radiation. Remember that UV is the type of non-visible radiation produced by the sun.
In both cases (vitamin D supplementation and UV exposure), the area covered by tumors was significantly reduced. However, only UV exposure reduced the progression of the tumors to malignancy (full-fledged cancer).
The authors made the following statement regarding their somewhat surprising finding:
“Mortality from colorectal cancer decreases as ambient levels of UV radiation increase, suggesting that UV exposure is critical to the prevention of the disease. This study demonstrates the biological plausibility in mice of a causal relationship between moderate chronic UV irradiation or vitamin D supplementation and an impairment of outgrowth of primary intestinal cancer. While both UV irradiation and vitamin D supplementation decreased the overall area covered by tumors, only UV exposure inhibited malignant progression” [emphasis mine].
The Garland brothers in 1980 demonstrated that Sun exposure was inversely associated with colon cancer.[2] They assumed that sun-stimulated vitamin D was the mechanism that caused the inverse association, but it now seems that sun exposure has cancer preventive mechanisms beyond vitamin D.
Remember: sunlight alone will always be better than vitamin D alone, because there are many healthful chemicals, beyond vitamin D, that are produced by sun exposure.
[1] Heggert Rebel, Celia Dingemanse-van der Spek, Daniela Salvatori, Johannes P.T.M. van Leeuwen, Els C. Robanus-Maandag and Frank R. de Gruijl. UV exposure inhibits intestinal tumor growth and progression to malignancy in intestine-specific Apc mutant mice kept on low vitamin D diet. Int J Cancer. 2015 Jan 15;136(2):271-7.
[2] Garland CF, Garland FC. Do sunlight and vitamin-D reduce the likelihood of colon cancer? Int J Epidemiol 1980;9:227–31.
By Marc Sorenson, EdD, Sunlight Institute…
In the previous blog, we noted that sun exposure was associated with a reduced risk of the deadly bacterial infection called sepsis. In reality, UV therapy was used to treat many kinds of infections decades ago, when sun exposure was widely known as a bactericide.
Dr. Zane Kime, in his book, Sunlight could Save Your Life, reviewed the results of research conducted between 1886 and 1909 and showed that the following bacteria were killed by ultraviolet light: anthrax, plague, streptococci, tubercle bacillus, cholera, staphylococcus, colon bacillus and dysentery bacillus.[1] Sun was virtually forgotten with the advent of antibiotic drugs, but now the interest has returned.
While watching a newscast, I noticed the news ticker along the bottom of the screen announcing, “Sunshine is the most effective anti-infection therapy.” But is this really news? Dr. Kime cites several early studies on sun and infectious diseases that were performed about the same time as the advent of antibiotics. Reports in the scientific literature in the 1940s showed that sun killed infectious bacteria or viruses. Kime states …“a number of patients, having such various infections and diseases as blood poisoning [septicemia], childbirth infections, peritonitis, viral pneumonia, mumps, and bronchial asthma were treated with ultraviolet light therapy to their blood.”[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] They were, in fact, treated very successfully.
Dr. Kime also cited research showing that UV therapy killed the flu virus outside the body[12] and destroyed cancer-producing viruses.[13] He reported good results in his own practice in treating fungal infections with sun therapy.
The ancients knew of the marvelous healing effects of sun exposure, and Dr. Kime knew even more in 1980 as he reviewed the literature. We need more people who are willing to promulgate the truth about our kindly friend, the sun.
[1] Kime, Z. Sunlight Could Save Your Life. World Health Publications, Penryn, CA 1980 pp 180-81.
[2] Miley, G. The Knott technic of ultraviolet blood irradiation in acute pyogenic infections. New York J Med 1942;42:38.
[3] Miley, G. The Knott technic of ultraviolet blood irradiation in acute pyogenic infections. New York J Med 1942;42:38.
[4] Rebbeck, E. Ultraviolet irradiation of auto-transfused blood in the treatment of puerperal sepsis. Amer J Surg 1941;54:691
[5] Rebbeck, E. Ultraviolet irradiation of autotransfused blood in the treatment of postabortal sepsis. Amer J Surg 1942;55:476.
[6] Rebbeck, E. Ultraviolet irradiation of the blood in the treatment of escherichia coli septicemia. Arch Phys Ther 1943;24:158.
[7] Rebbeck, E. The Knott technic of ultraviolet blood irradiation as a control of infection in peritonitis. Amer J Gastroenterol 1943;10:1-26
[8] Hancock, V. Irradiated blood transfusions in the treatment of infections. Northwest Med 1934;33:200.
[9] Barrett, H. Five years experience with hemo-irradiation according to the Knott technic. Am J Surg 1943;61:42
[10] Barrett, H. The irradiation of auto-transfused blood by ultraviolet spectral energy: results of therapy in 110 cases. Med Clin N Amer 1940;24:723
[11] Miley, G. The present status of ultraviolet blood irradiation. Arch Phys Ther 1944;25:357.
[12] Hollaender, A. The inactivating effect of monochromatic ultraviolet radiation on influenza virus. J Bact 1944;48:447.
[13] Heding LD, Schaller JP, Blakeslee JR, Olsen RG. Inactivation of tumor cell-associated feline oncornavirus for preparation of an infectious virus-free tumor cell immunogen. Cancer Res 1976;36:1647.
By Marc Sorenson, EdD, Sunlight Institute…
Sepsis is a deadly disease, defined as infection of the tissues by bacteria. It can spread throughout the body and blood, where it is known as septicemia. Sepsis accounts for 500,000 emergency-room hospital visits per year in the USA, and the typical stay is nearly five hours.[1] It is one of the most deadly of medical conditions and often results in multiple organ failure.[2] It is, in fact, one of the top-ten causes of death. It is more common than heart attack, and claims more lives than any cancer.[3] Yet, much of the population has never heard of it.
Antibiotics have not been effective against severe sepsis and in some cases may exacerbate the disease.1 Sepsis is also the most common cause of death in critical-care patients in non-coronary intensive care units.[4]
Does regular time in the sun act to protect against this deadly disease? The research indicates that it does. In both the USA and UK, the disease is more common in winter than summer and higher in the Northeast than in the Southwest.
It is likely that vitamin D, produced by sun exposure, is the mechanism by which sepsis risk is decreased in summer.[5] According to Dr. William Grant, reports have shown that vitamin D upregulates human cathelicidin, LL-37, which has antimicrobial as well as anti-endotoxin activity.[6] However, we must never lose sight of the other benefits of sun exposure beyond vitamin D, which is only one of the sun’s beneficial photoproducts. Staying out of the sun—and using deadly chemical sunscreens to block life-giving sun exposure—are two of the biggest blunders ever made in the history of health disasters.
It is also interesting to note that in Australia, melanoma rates skyrocketed between 1980 and 2000.[7] 1980 was the year when a massive anti-sun campaign, called “Slip, Slop, Slap” began. Sepsis rates jumped simultaneously with melanoma and coincided with the widespread use of sunscreens. During this campaign, there was also an increase in viral respiratory infections, most cancers, and congestive heart failure.[8]
Remember that hospitals are not sterile environments. Try to stay away from them except in cases of dire need. Get some moderate, non-burning midday sun exposure instead—without using sunscreens.
[1] Wang, H. et al. National estimates of severe sepsis in United States emergency departments. Crit Care Med 2007;35:2461-2.
[2] Mookherjee, N. et al. Cathelicidins and functional analogues as antisepsis molecules. Expert Opinions on Therapeutic Targets 2007;11:993-1004.
[3] World Sepsis Day web page. September 13, 2015. http://world-sepsis-day.org/?MET=SHOWCONTAINER&vCONTAINERID=11. Accessed February 25, 2016.
[4] Florian B Mayr, Sachin Yende, and Derek C Angus. Epidemiology of severe sepsis. Virulence 2014, 5:1, 4-11.
[5] Karin Amrein, Paul Zajic, Christian Schnedl, Andreas Waltensdorfer, Sonja Fruhwald, Alexander Holl,
Tadeja Urbanic Purkart, Gerit Wünsch, Thomas Valentin, Andrea Grisold, Tatjana Stojakovic, Steven Amrein, Thomas R Pieber and Harald Dobnig. Vitamin D status and its association with season, hospital and sepsis mortality in critical illness. Critical Care 2014, 18:R47
[6] Grant WB Solar ultraviolet-B irradiance and vitamin D may reduce risk of septicemia. Dermatoendocrinol. 2009 Jan;1(1):37-42.
[7] Montague M, et al. Slip! Slop! Slap! and SunSmart, 1980-2000: Skin cancer control and 20 years of population-based campaigning. Health Educ Behav. 2001;28:290–305
[8] Grant WB Solar ultraviolet-B irradiance and vitamin D may reduce risk of septicemia. Dermatoendocrinol. 2009 Jan;1(1):37-42.
By Marc Sorenson, EdD, Sunlight Institute…
Several scientific investigations have linked sunlight deprivation to nearsightedness (myopia), and many of these have been discussed on previous blogs. The latest used rhesus monkeys as subjects.[i] These monkeys were reared either with natural lighting for three hours daily or indoor lighting. As we might expect, those that were raised with indoor lighting developed myopia, whereas those raised with natural lighting did not develop the disorder. The eye dimensions became abnormal in the monkeys that were exposed only to indoor light, and problems with refraction, due to eye elongation, were noted.
There is no doubt that sun deprivation is a factor that leads to blindness. Others obviously feel the same way. Here I quote from Dr. Hobday, writing in Perspectives of Public Health: “A century ago, it was widely believed that high levels of daylight in classrooms could prevent myopia, and as such, education departments built schools with large windows to try to stop children from becoming short-sighted. This practice continued until the 1960s, from which time myopia was believed to be an inherited condition. In the years that followed, less emphasis was placed on preventing myopia. It has since become more common, reaching epidemic levels in East Asia. Recent research strongly suggests that the amount of light children get as they grow determines whether they will develop short sight; however, evidence that daylight in classrooms prevents myopia is lacking. Given the rapid increase in prevalence among school children worldwide, this should be investigated.”[ii]
Others are also concerned and state that eye elongation and progression of myopia decrease in periods with longer days and to increase in periods with shorter days.[iii] According to these researchers, “children should be encouraged to spend more time outside during daytime to prevent myopia.”
[i] Wang Y, Ding H, Stell WK, Liu L, Li S, Liu H, Zhong X. Exposure to sunlight reduces the risk of myopia in rhesus monkeys. PLoS One. 2015 Jun 1;10(6).
[ii] Hobday R. Myopia and daylight in schools: a neglected aspect of public health? Perspect Public Health 2015 Mar 23.
[iii] Cui D, Trier K, Munk Ribel-Madsen S. Effect of day length on eye growth, myopia progression, and change of corneal power in myopic children. Ophthalmology. 2013 May; 120(5):1074-9
By Marc Sorenson, EdD. Sunlight Institute…
Dr. Richard Weller has promoted sun exposure as a method of increasing nitric oxide (NO) in the vascular system, thereby lowering the risk of heart disease.[1] NO is a potent vasodilator that lowers blood pressure, which according to the World Health Organization, is the leading cause of premature death and disease worldwide.1 But NO may have other beneficial effects.
There is also research showing that NO, which is also an oxidant, has the ability to retard or reverse tumor growth, making it a potential anti-cancer therapy.[2] The problem with this of course, is that if it is used as an anticancer treatment, the oxidation has the potential to harm other systems of the body; After all, that is why we use antioxidants. However, the body beautifully controls the natural use of oxidants to specifically target tumors and leave healthy tissue untouched. As one group of researchers states: “…there is considerable controversy and confusion in understanding its role [NO) in cancer biology. It is said to have both tumoricidal as well as tumor promoting effects which depend on its timing, location, and concentration.[3]
The best way to use NO, in my opinion, is to let nature take its course and use sun exposure to produce NO. Then, the body’s natural physical process will use oxidation to destroy tumors and simultaneously reduce the risk of cancer.
Safely enjoy the sun.
[1] Richard B. Weller. Sunlight Has Cardiovascular Benefits Independently of Vitamin D. Blood Purif 2016;41:130–134.
[2] Jordi Muntané and Manuel De la Mata. Nitric oxide and cancer. Nitric Oxide and Cancer. Journal List. World J Hepatolv.2(9); 2010 Sep 27.
[3] Sheetal Korde Choudhari, Minal Chaudhary, Sachin Bagde, Amol R Gadbail, and Vaishali Joshi. Nitric oxide and cancer: a review. World J Surg Oncol. 2013; 11: 118.