Mastic Suppresses Human Leukemia Cells

Mastic—A Weapon for Good Health

Mastic Suppresses
Human Leukemia Cells

It also inhibits the formation of new blood vessels that feed various malignancies
By Richard P. Huemer, M.D.

I don’t know what the hell this ‘logistics’ is that
Marshall is always talking about, but I want some of it.

— Admiral E. J. King

hen Napoleon famously said that an army marches on its stomach, he did not mean to compare his soldiers to a legion of escargots. Instead, he wanted to make a point about logistics: an advancing army must not outpace its supply lines. If the troops cannot be nourished, they will languish, and the invasion will fail.

Like so many of us, Napoleon did not always heed his own wisdom. In 1812, he led a force of 500,000 men to conquer Russia. Seeing the weak link in his logistics, the Russians sequestered most of their local food sources. Napoleon reached Moscow but was then forced to retreat (under brutal winter conditions) because his troops were enfeebled by starvation and cold. Thus was the cancer of continental conquest halted in its tracks.

Cancer’s Conquest Requires Nourishment

It’s fitting to liken military conquest to cancer. Nature created the equivalent of invading hordes, scorched earth, chemical and biological warfare, etc., eons before human beings existed to invent such travesties. Certainly in its later stages, cancer resembles nothing so much as a conquest of the body by overwhelming numbers of invaders (albeit homegrown ones rather than foreigners).

Like Napoleon’s soldiers, cancer cells cannot thrive and conquer without nourishment; figuratively speaking, they march on their stomachs. For example, as solid tumors expand in size, they require ever longer “supply lines” of blood vessels in order to keep growing. That’s where VEGF (vascular endothelial growth factor) comes in—and now would be a good time to read the sidebar “The Trouble with VEGF.”

The Trouble with VEGF

VEGF—sounds wholesome and nutritious, doesn’t it, like something a vegan might eat. But vascular endothelial growth factor has nothing to do with vegetables. It’s a peptide (a small protein) that’s produced mainly in the endothelium, the layer of smooth, flat cells that line the inside of our blood vessels. All endothelial cells manufacture VEGF in order to stimulate the growth of new blood vessels (starting with tiny capillaries), a process called angiogenesis.

Like many natural processes, angiogenesis can be either beneficial or harmful, depending on the circumstances—and so, therefore, can VEGF.

On the plus side, VEGF is released continuously by endothelial cells in order to maintain the microvasculature of our tissues. Additional release of VEGF is triggered when tissues sense that they’re being inadequately nourished—e.g., under conditions of ischemia (low blood flow), hypoxia (low oxygen), and hypoglycemia (low blood sugar)—or when new blood vessels are needed for wound healing. Angiogenesis can help compensate for impaired circulation to the heart or the brain caused by obstructed coronary or cerebral arteries. Networks of blood vessels develop and bypass the obstruction, bringing some nourishment to the starved tissues.

But angiogenesis has a dark side too. It’s stimulated by most tumor cells and plays a key role in the progression of many cancers by providing the needed blood supply. Here VEGF becomes our inborn enemy, because it orchestrates this process by activating several biochemical signaling pathways required for angiogenesis. The signals are transmitted via VEGF receptors in cell walls—large protein molecules that act as “docking stations” for the much smaller VEGF molecule. In so doing, the receptors stimulate molecules inside the cells to respond in specific ways, leading to the desired—no, make that undesired—result.

If you had a cancer, you would want to starve it, not feed it. The same would be true if you had rheumatoid arthritis, a disease in which chronic inflammation results from an imbalance between inducers and inhibitors of angiogenesis. And then there’s age-related macular degeneration, the leading cause of blindness in people over 50. The most destructive form of this disease is the “wet” form, which is characterized by angiogenesis that can lead to hemorrhage in the retina. New hope for controlling wet macular degeneration has been found in a treatment in which genetically engineered VEGF inhibitors are injected directly into the eye. (Ouch! But it’s worth it.)

OK, now that you know all about VEGF, let me tell you a little more about it. It’s vital not only for the growth of solid tumors but also for the development of blood-based malignancies, such as leukemia, which is a cancer (uncontrolled proliferation) of leukocytes, or white blood cells. Like erythrocytes (red blood cells), leukocytes are manufactured in our bone marrow, and if excessive angiogenesis should develop there, caused by excessive release of VEGF, the result can be leukemia (of which there are many varieties).

It sounds as though VEGF, a good guy that can turn bad on us, ought to be made the target of some “chemical warfare” through nutritional supplements. Let’s see what can be done.

Mastic Is Effective Against Various Cancers

On the battlefield, when a logistical failure forces soldiers to improvise, it’s traditional to take credit for repairing some piece of equipment with “chewing gum and baling wire.” Chewing gum can be handy for repairing the body, too. For example, chewing mastic gum can help prevent tooth decay, heal and prevent peptic ulcers; and curb inflammation related to numerous serious diseases.*

*For the stories, see “Chewing Mastic Gum Can Prevent Tooth Decay,” “Mastic and Licorice Are Good for Your Belly,” and “Mastic Helps Curb Inflammation” in the March, June, and September 2006 issues, respectively.

Mastic is a gum resin from the Mediterranean mastic tree (Pistacia lentiscus), whose name derives from the same Greek root as our word masticate. People have been masticating this natural resin for millennia—and they’ve been eating it too. When it’s ingested rather than chewed, mastic is particularly potent in protecting the gastrointestinal tract from gastritis, peptic ulcers, and stomach cancer (see “Mastic Kills the Bugs that Cause Gastritis and Ulcers,” July 2003). And mastic appears to be effective against other cancers as well (see “Mastic Kills Colon Cancer Cells” and “Mastic May Help Against Prostate Cancer” in the September 2005 and July 2006 issues, respectively).

Mastic oil contains dozens of
identified chemical compounds, one
of which has been found in rodent
studies to be effective in preventing
and treating various cancers.

Mastic oil (the oil extracted from the gum resin) contains dozens of identified chemical compounds, one of which, perillyl alcohol, has been found in rodent studies to be effective in both preventing and treating various cancers.1 Although this compound constitutes only about 1% of mastic oil, it appears to be especially potent and is currently in phase I–II clinical trials. Significantly, perillyl alcohol also inhibits angiogenesis (remember cancer’s supply lines?).

Is Whole Mastic Better than “Partial Mastic”?

A Greek research team had discovered perillyl alcohol’s antiangiogenic effect, and they naturally wondered whether using the whole mastic oil would be better than the alcohol alone. In other words, why not seek the maximum potential benefit? Since mastic’s well-known antibacterial action is believed to be the synergistic result of a number of its chemical components working together, it’s reasonable to assume that the same might be true of its antiangiogenic action.2

Same Cancer Rate, but More Survivors

Earlier this year, the nation’s leading cancer organizations issued their “Annual Report to the Nation on the Status of Cancer, 1975–2003, Featuring Cancer among U.S. Hispanic/Latino Populations.”1 Their conclusion: overall, Americans’ risk of dying of cancer continues to decrease, as it has since the early 1990s.

Over the past decade, men’s decrease in cancer mortality has been twice that of women (1.6% per year vs. 0.8 % per year), largely because their rate of smoking has decreased. Nonetheless, the death rate for men remains 46% higher than for women. Death rates decreased for 11 of the 15 most common cancers in men and for 10 of the 15 most common cancers in women.

The decrease in death rates was attributed in part to the declining use of tobacco, earlier detection through screening, and more effective treatments. Still, cancer remains the second leading cause of death in the United States, after heart disease.

By contrast with the declining death rates, the rate of new cancer diagnoses did not change in 2003. Men had decreased incidence rates for colorectal, stomach, oral, and lung cancers, but higher rates for prostate cancer, myeloma, leukemia, and cancers of the liver, kidney, and esophagus. Women developed fewer colorectal, uterine, oral, stomach, and cervical cancers, but they had more lung cancer.

A special feature of the report was a section on cancer in Hispanic (which encompasses Latino) populations, based on 90% of the U.S. Hispanic population. In general, Hispanics had lower incidence rates for most cancers than did non-Hispanic Caucasians, although they were less likely to be diagnosed early for some cancers, and the rates of some childhood cancers were higher.


  1. Fox M. Cancer deaths fall, new diagnoses stable. Reuters Health, Sep. 7, 2006.

This approach comes naturally to holistic physicians and herbalists, and it has obvious practical value—often great value. It’s less appealing, however, to most mainstream physicians and research scientists, who prefer to study things that can be analyzed with much greater precision than chemically “messy” herbal extracts, whose complex compositions can vary significantly—sometimes greatly—from batch to batch.* Their scientific approach may be less practical in the short run, but it promises greater payoffs in the long run, in terms of reliable knowledge that can be generalized and extended to other spheres, both theoretical and practical.

*It’s also useful to remember that many plants are poisonous—natural does not mean safe—and that even some herbal extracts that are otherwise beneficial may contain potentially harmful compounds that should be removed by selective extraction methods. Licorice and cinnamon are two examples.

Why Use Leukemia Cells?

Well, that was a digression. In any case, the Greek researchers did take the holistic approach to see whether mastic oil would suppress tumor-cell growth and angiogenesis.1 Using perillyl alcohol for purposes of comparison, they performed parallel tissue-culture experiments, employing a variety of techniques to measure cell growth and survival, VEGF levels, angiogenesis, and certain chemical signals by which some cells communicate with one another in promoting the growth of tumors and new blood vessels.

The cells they used were of three kinds: certain strains of human leukemia cells and mouse melanoma (skin cancer) cells, and human endothelial cells. But why leukemia cells? After all, unlike solid tumors, which require VEGF-induced vascular supply lines to provide them with the blood they need, most leukemia cells float around in the bloodstream, where there are plenty of nutrients available to them.

As mentioned earlier, however, leukemia cells are closely linked with angiogenesis through their origin in bone marrow. Furthermore, they not only produce VEGF themselves (as do endothelial cells), they also respond to VEGF (via receptors in their cell walls); this allows them to push their own “on” button, so to speak, for cell growth and propagation—which is the last thing you want in cancer cells.

Mastic Inhibits Tumor-Cell Growth and Angiogenesis

Mastic gum
The researchers found that mastic oil significantly inhibited both growth and survival of the human leukemia and mouse melanoma cells; these effects occurred in proportion to the concentration of mastic oil used and the incubation time. Mastic’s action was apparently due primarily to its targeting of VEGF, the levels of which were significantly reduced. Also reduced were the proliferation and differentiation of human endothelial cells, which are key factors in angiogenesis.

The effects of perillyl alcohol in this study were the same as those of mastic oil and were roughly comparable (sometimes greater) in magnitude. But the relative magnitudes of the observed effects depend on the concentrations that were used, and when those were taken into account, the researchers concluded that mastic oil is more potent than perillyl alcohol alone, presumably owing to additive or synergistic effects of its biologically active constituents.

The authors concluded,

. . . our results suggest that mastic oil is a tumor and angiogenesis inhibitor targeting components of critical signaling cascades in both leukemia and ECs [endothelial cells]. If present findings are extended to other malignancies and to in vivo tumor models, they can form the basis for establishing mastic oil as a naturally occurring chemopreventive and antiangiogenic agent.

Doctors Are Not Barbarians

Napoleon must have been a cynical fellow. Among the many aphorisms attributed to him are that war is the business of barbarians, God fights on the side with the heaviest artillery, and women are nothing but machines for producing children. He also said, “Doctors will have more lives to answer for in the next world than even we generals.”

Well, that’s not true anymore. Although they fight many battles, doctors aren’t exactly barbarians, and in any case, they have heavier artillery than they used to. I like to think that mastic and its ilk are harbingers of a new (old) generation of weapons for health—natural and relatively nontoxic substances for targeting the biochemical mechanisms that have gone awry in sick people.


  1. Loutrari H, Magkouta S, Pyriochou A, Koika V, Kolisis FN, Papapetropoulos A, Roussos C. Mastic oil from Pistacia lentiscus var. chia inhibits growth and survival of human K562 leukemia cells and attenuates angiogenesis. Nutr Cancer 2006;55(1):86-93.
  2. Koutsoudaki C, Krsek M, Rodger A. Chemical composition and antibacterial activity of the essential oil and the gum of Pistacia lentiscus var. chia. J Agric Food Chem 2005;53:7681-5.

Dr. Richard P. Huemer received his M.D. from UCLA and did postdoctoral research in cancer immunology at CalTech. He has specialized in orthomolecular medicine for most of his career, has written and lectured extensively on alternative medicine, and has served on the editorial boards of professional journals. His published books include The Roots of Molecular Medicine: A Tribute to Linus Pauling and, with coauthor Jack Challem, The Natural Health Guide to Beating the Supergerms.

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