The first step in the formation of a narrowed artery is the manufacture of cells (smooth muscle cells) which line the inside of the artery. Then cholesterol gets deposited in these cells after they have increased in number. The increased cells together with cholesterol is called a plaque. There is good evidence that these cells come from a single cell, that is, they are cloned from one common cell. Cloning is a form of cancer. (30) This situation can be produced in chickens by feeding. them carcinogens (benzo(a)pyrene and dimethylbenzanthracene), chemical substances that produce cancer. These particular carcinogens cause an increase in the number and rate of formation of plaques without altering the blood level of cholesterol. In humans, these types of carcinogens (hydrocarbons) are carried by certain proteins (low density lipoproteins) which also carry cholesterol. More curiously, an enzyme called aryl hydrocarbon hydroxylase, present in cells of the inner walls of arteries, can activate hydrocarbon carcinogens to start proliferating the lining cells. (31) Therefore, if we eat food contaminated with these hydrocarbons or are otherwise exposed to them so that they get into our bloodstream, atherosclerosis may begin to develop. Of course this is just one of many factors involved in the development of atherosclerosis.

R.W. Pero and colleagues have shown a relationship between high blood pressure and cancer. (32) The study shows that the higher the blood pressure and the older the person, the more alterations of DNA that occur in cells. The more abnormal the DNA content of a cell, the snore often it will lose control and develop into a cancer. There is some evidence that people with high blood pressure have an increased risk of developing breast cancer, (33) colon cancer, lung cancer, and other cancers.

Hormonal Risk Factors
Hormones influence a cell's growth and development, so if there is an excess or deficit of hormones in the body, then cells will not function properly and may grow abnormally or aberrantly and become cancer cells.

Women who have never been pregnant have a higher risk of developing breast cancer than women who do have children; and women who become pregnant before age 20 have a reduced risk. Women whose mothers or other close relatives have breast cancer have three times the normal risk of getting breast cancer. Women who do not menstruate during their lifetime have a three to four times higher risk of developing breast cancer after the age of 55. A lower risk of breast cancer is seen in women whose ovaries cease to function or are removed surgically before age (35).

There has been considerable controversy over whether oral contraceptives can cause breast and liver cancer. Many studies seem to indicate that hormones used in birth control pills are a risk factor for breast or liver cancer. (35,36) Estrogens in these oral contraceptives can cause benign liver growths as well, which can bleed extensively and cause problems related to bleeding.

Daughters of women who received DES (diethylstilbestrol) therapy during pregnancy have developed cancer of the cervix and vagina. Sons of women who took DES have a higher risk of developing cancer of the testicles because DES causes urinary tract abnormalities including undescended testicles, which, if not corrected surgically before age 6, can develop into cancer of the testicles. (37) Furthermore, women exposed to these same synthetic estrogens in adult life have a higher risk of developing cancer of the cells that line the inside of the uterus (endometrial cancer). Male hormones can predispose to both benign and malignant liver tumors.

Obesity is directly correlated with breast cancer (38-41) and endometrial cancer. (42)

Fibrocystic breast disease, a benign disease that affects 50 percent of all women sometime during their lives, probably represents a hormone imbalance. If a woman has had the disease over many years, she is at an increased risk of developing breast cancer. (43,44) Recently, fibrocystic breast disease has appeared to respond to certain nutrients and dietary modification.

Sexual-Social Risk Factors
Cancer of the cervix is associated with having sexual intercourse at an early age and with having multiple male sex partners. The earlier the age of the female when she first has sexual intercourse, and the greater the number of male partners she has, the higher is her risk of getting cancer of the cervix. Sexual intercourse with uncircumcised male partners may also contribute to a woman's risk of developing cervical cancer.

Cancer of the penis is a very rare disease in the United States. There is almost universal agreement that one primary risk factor is responsible for this cancer--poor hygiene, especially in the uncircumcised male. Secretion and different organisms retained under the foreskin produce irritation and infection, which are thought to predispose to cancer cellular changes. (45)

There is an epidemic outbreak of Kaposi's sarcoma in sexually active male homosexuals. (44-48) Kaposi's sarcoma is a cancer of the skin, mucous membranes, and Iymph nodes. Those affected have an acquired immunodeficiency syndrome (AIDS). In addition to Kaposi's sarcoma, male homosexuality is a risk factor for two other cancers: cancer of the anus (49) and cancer of the tongue.

Sexually active male homosexuals in good health can have a normal or abnormal immune system. Many with an abnormal immune system appear quite healthy. Some with a malfunctioning immune system have had Kaposi's sarcoma and/or fatal or life-threatening infections caused by Pneumocystis carinii. (50,51)

The immune impairment from AIDS seen in sexually active male homosexuals, intravenous drug users, prostitutes, and heterosexuals is now clearly related to infection by the HIV virus. Other risk factors leading to human susceptibility to HIV include amyl nitrite, a drug used as a sexual stimulant. Amyl nitrite produces a profound impairment of the immune system, especially the T Iymphocytes. (52) Also, immunological abnormalities are seen more often in homosexuals who have many sexual partners than in those who have only one partner.

Viral Risk Factors
Viruses have been shown to directly cause cancer in fish, birds, frog* and almost every mammal. Over one hundred viruses capable of causing cancer have been identified. Two human cancers, T cell leukemia and T cell Iymphoma, have been shown to be caused directly by viruses. Perhaps all the other white blood cell tumors will also be shown to be caused by viruses.

In the following chapters we will review nutritional risk factors, other risk factors that can lead to the development of cancer, and ways that the risk factors can be modified.

Following are a few examples of persons with various risk factors, their relative degrees of risk for developing cancer, and what they should do to modify those risks and thereby reduce their chance of developing cancer (and/or cardiovascular disease). After each risk factor the score is indicated in parentheses.

Consider Linda, a 56-year-old (C) New Jersey (B) housewife (O). She is 5 feet 5 inches tall, weighs 160 pounds (B), eats red meat daily, eats several eggs per week, drinks milk daily, consumes very little fiber-containing foods, and does not eat a balanced diet (A). She also smokes two packs of cigarettes a day, which has done for over fifteen years (A). Linda drinks socially (0) and has never had cancer (0), but her mother had breast cancer (B). She started having sexual intercourse at age 20 (0), first got pregnant at age 24 (0), has a history of fibrocystic breast disease (C), never had any radiation (0), and is relatively easygoing (0).

SELF-TEST

What is your risk of developing cancer? Take the following Cancer Risk Factor Assessment Test to determine your risk according to your diet, weight, age, lifestyle, and other factors discussed in this chapter. After you assess which factors pose a risk, you can begin to modify them according to my recommendations. Then take the test again to see if your overall risk has been reduced.