Jewish World Review July 26, 2002 / 17 Menachem-Av, 5762

Breast Cancer: Nature vs. Nurture

By Robert A. Wascher, M.D., F.A.C.S. | At the present time, only two gene mutations (BRCA-1 and BRCA-2) have been identified as risk factors for inheritable breast cancer, and only about 10% of all breast cancer tumors have either of these two gene mutations. Therefore, it is assumed that families who have multiple close relatives with breast cancer, and who are all free of BRCA mutations, may have as yet undiscovered genetic mutations in play. A new study in the current issue of the British Journal of Cancer has found evidence, albeit indirectly, of additional inheritable gene mutations in a study of 2310 identical and fraternal (non-identical) twin women.

In this study, fraternal twin sisters of women with breast cancer were found to experience 1.7 times the risk (or a 70% increased risk) of developing breast cancer when compared to a non-twin woman with the same personal and family history risk factors. When the identical twins were assessed, the twin sisters of women with breast cancer were found to be at 4.4 times the risk of developing breast cancer (or a 340% increased risk). Using complex statistical calculations to assess potential known and unknown risk factors, the researchers found that the most likely explanation for these findings was the existence of as yet undiscovered breast cancer susceptibility genes.

As the human genome, or genetic code, is fully unraveled, additional genetic abnormalities that predispose to an increased risk of breast cancer are certain to be found. Understanding the basis of these genetic predispositions offers the best hope of improved screening, diagnosis and treatment of breast cancer.


C-reactive protein (CRP) is a blood marker of inflammation that has been linked to an increased risk of coronary artery disease in a number of research studies. At the same time, it is well-known that increasing levels of cardiorespiratory fitness are associated with a decrease in the risk of coronary artery disease. A new study in the journal Circulation has assessed the relationship between these two "heart health" factors for the first time. A total of 135 women volunteers were assessed for CRP levels in the blood, and for cardiorespiratory fitness through the use of a treadmill exercise test. This study determined that decreasing levels of aerobic fitness were associated with higher levels of CRP in the blood. The authors conclude that higher levels of fitness appear to reduce, by some unknown mechanism, the inflammatory changes that increase CRP production. Thus, this study provides yet more evidence of the pervasive health benefits that arise from regularly engaging in at least moderate exercise!


There are more than 30,000 people in the United States who are currently awaiting the availability of a suitable kidney for transplantation. Just over 10,000 donor kidneys are matched up each year with people who have suffered the irreversible failure of their own kidneys.

Although hemodialysis can prolong the lives of most people with kidney failure, dialysis cannot replace the function of normal kidneys, and is associated with many serious and even life-threatening complications. At the present time, donor kidneys are taken from volunteer "living donors" (usually, but not always, a family member), or from brain-dead volunteer donors with still beating hearts. In the latter case, the kidneys are removed from a person who has no remaining brain function, but whose heart continues to pump blood to the kidneys and other vital organs.

In most cases, brain-dead patients rapidly experience a progressive loss of heart function as well, often within a few hours of losing brain function. This factor often translates into a very brief window of opportunity during which the donor kidney can be recovered and prepared for transplantation.

After the heart has stopped beating, the kidneys begin to deteriorate due to loss of blood flow, and have generally not been considered transplantable at this stage. In this week's issue of the New England Journal of Medicine is a Swiss study that looked at the transplantation of kidneys from donors who had lost all cardiac function as well as brain function.

The authors transplanted 122 kidneys taken from donors with a heartbeat and 122 kidneys from donors without a heartbeat. They then followed both groups of transplant recipients for 15 years. Recipients receiving kidneys from donors without a heartbeat experienced a significant delay in the onset of function by the transplanted kidney in 48% of cases, while the kidneys taken from donors with a heartbeat had delayed function in 24% of cases.

However, and most importantly, the long-term rate of kidney transplant survival was essentially equal in both groups of patients: 79% for the kidneys taken from donors without a heartbeat and 77% for the organs taken from donors with a heartbeat.

This is very good news, indeed, as it has the potential to dramatically increase the number of donor kidneys available for transplant each year. This study, although involving a relatively small number of patients, should have a rapid and dramatic impact on the practice of kidney transplantation. Various other organs used for transplants have different individual tolerances for the duration of blood flow loss.

Therefore, additional research will be necessary to determine whether or not other commonly transplanted organs, such as the liver, heart, pancreas and intestines, can safely endure brief periods of ischemia (loss of blood flow) and still retain their ability to function following transplantation.


All travelers know that flying on an airplane full of sneezing and coughing fellow passengers means that you will likely be reaching for your hankie the following day too. There has been a great deal of controversy over the practice by most major airlines of recirculating cabin air. Since the air at flight altitudes is very cold and very dry, it must be processed for the comfort of airplane passengers, and this costs money in the form of increased fuel consumption.

So, many airlines economize by recirculating up to 50% of the cabin air, and then mix this recirculated air with small volumes of fresh air from outside the aircraft. It has long been assumed that this practice increases the risk of infectious disease transmission due to the decreased number of cabin air exchanges that occur with recirculation, and based upon studies of workers in buildings that also recirculate air.

In this week's Journal of the American Medical Association, 1,100 airplane passengers were asked to complete a questionnaire prior to boarding a flight from San Francisco to Denver, and were again interviewed 5 to 7 days after completing their flight. Recirculated air was present on the flights traveled by 53% of the study volunteers, while 47% of the study participants flew on planes with 100% fresh cabin air.

Basically, the study found no significant difference in the incidence of respiratory infections between either group of travelers. Both groups experienced an approximately 20% incidence of cold symptoms following their flights. While this study does not address other health-related concerns about recirculated airplane cabin air, it does tend to dispel the notion that recirculating virus-ladened air (at least up to the 50% level) increases the risk of upper respiratory disease transmission. It appears more likely now that the factors most responsible for respiratory virus transmission on airplanes include the confinement of large numbers of people within a small space (and for hours at a time), and the transmission of viral particles by person-to-person contact. These are, of course, the same viral transmission risk factors that predominate among earthbound people.

JWR contributor Dr. Robert A. Wascher is a senior research fellow in molecular & surgical oncology at the John Wayne Cancer Institute in Santa Monica, CA. Comment by clicking here.


07/19/02: PCBs & the Gender of Babies; Breastfeeding & the Risk of Breast Cancer; More Bad News About Hormone replacement Therapy

07/12/02: A cancer surgeon's perspective on hormone replacement therapy

07/08/02: Hormone replacement therapy & the risk of disease; more good news about statins; antioxidant vitamins & disease prevention; more

06/28/02: Antioxidants & the Risk of Alzheimer's Disease; Effects of Exercise on the Hearts of Patients with Mild Hypertension; Statins reduce cardiac events following angioplasty; more

06/21/02: Sex & violence and Advertising: Do Advertisers Get What they Pay For?; Don't Drink the Water (or the Salsa Either!); Vasectomy & Prostate Cancer Risk; Update on Smoking & Disease

06/14/02: Young Men, Obesity & Heart Disease; Breastfeeding & Obesity; Irritable Bowel Syndrome & rectal pain threshold; more data on cox-2 inhibitors & cancer; more

06/07/02: New coronary artery stent reduces risk of restenosis; possible cause of Parkinson's Disease identified; more

05/31/02: New biological insights into obesity & weight loss; broccoli kills cancer-causing stomach bug; anti-inflammatory drugs and the risk of heart attack

05/24/02: Molecular detection of tumor cells in the blood & prognosis; Cox-2 & breast/lung cancers; BRCA2 gene mutations & the risk of breast cancer; breast density & the risk of breast cancer

05/19/02: Moderate alcohol intake and blood sugar levels; more good news for tea drinkers; blood potassium levels & the risk of cardiovascular disease; ethnic differences in diabetic complications

05/10/02: Tea drinkers and the risk of death following heart attack; duration of breastfeeding & adult intelligence; abdominal aortic aneurysms: surgery or observation?

05/03/02: Risk of adverse drug reactions from newly released medications; preoperative beta-blockers may reduce heart bypass deaths; shape-shifting plastics may alter surgical practice; weight loss supplement may cause liver damage
04/26/02: Angry young men & risk of premature cardiovascular disease; stay-at-home dads & risk of cardiovascular disease; more on the effects of statins; dairy consumption and the risk of pre-diabetes; smallpox vaccine: good to the last drop?
04/19/02: Change your sex by drinking water?; Anti-inflammatory RXs may reduce growth of breast cancer cells; radiation treatment reduces repeat narrowing of bypass grafts
04/05/02: Fish & Omega-3 fatty acid consumption and cardiac health; news briefs
04/05/02: Can coffee reduce your risk of tooth decay?; exercise & blood pressure; a single high-fat meal reduces coronary artery function
04/01/02: Pre-diabetes: a newly defined category of health risk; teen television viewing and subsequent aggressive behavior; the benefits of strength training in the elderly; more ...
03/22/02: Bacteria, antibiotics & heart disease; mammograms: the debate continues; calcium & the risk of colon cancer ... and more
03/15/02: Mammography debate continues; statins & fracture risk; physical fitness & the risk of death; other intriguing findings
03/08/02: Blows to the chest & sudden cardiac death; air quality & the risk of lung cancer; tomatoes and your prostate
03/01/02: Diet & the risk of ovarian cancer; lifetime risk of developing high blood pressure; Osteoporosis prevention with a once-a-year injection?
02/26/02: The continuing controversy regarding screening mammography
02/22/02: Lowering body temperature after heart attack improves outcome; A silver lining for the chronically sleep-deprived?
02/15/02: Hormone replacement therapy & the risk of breast cancer; use it or lose it: Alzheimer's disease & cognitive stimulation; stress, divorce & death; child daycare, infections & parental guilt
02/08/02: Possible breakthrough in early cancer diagnosis; mammography: the controversy continues; CPR techniques revisited
02/01/02: Antibiotics in livestock feed & human disease; genetic detection of early colon cancer in the stool; genetic analysis of breast cancers may help decide treatment
01/25/02: Drug increases lifespan (if you're a fly...); workplace attitudes and smoking cessation; effects of inadequate sleep on surgeons
01/18/02: Lifelong effects of premature birth; smokers under the knife; aspirin and cardiovascular health
01/11/02: Estrogen levels in the blood & breast cancer risk; Heart attack: sex and survival; dangerous lettuce invaders
01/09/02: Cancer & aging: Two sides of the same coin?
01/04/02: Vitamin a & the risk of hip fracture in postmenopausal women; ovarian cancer risk and oral contraceptives
12/28/01: Magnetic Resonance Imaging (MRI) detects coronary artery disease; new development in obesity research; adverse childhood experiences & the risk of suicide attempts
12/21/01: Vaccination of children controls hepatitis a in the community; a possible cure for sickle cell disease; leptin and the risk of heart attacks
12/14/01: Chernobyl and the Risk of Thyroid Cancer in hildren; children & obesity; gastroesophageal reflux disease update
12/07/01: Update on school shootings; new implantable heart-assist device approved for further evaluation; prevention of fungal infections in pre-term babies
11/30/01: Flu vaccination in asthmatics; low-tar cigarettes are not less harmful; beans and your heart
11/21/01: Modified smallpox vaccine may reduce risk of cervical cancer; New approach to breast cancer diagnosis; New non-invasive prenatal diagnostic test for down's syndrome
11/16/01: Cholesterol-lowering drugs reduce risk of heart attack; supplemental radiation therapy reduces risk of breast cancer recurrence; brains of women may answer age-old questions
11/09/01: Bio-warfare (redux); my gray matter is bigger than yours; mad elk disease?
11/02/01: Making sense of bio-warfare
10/26/01: The impact of mammography on deaths due to breast cancer; diet & exercise may slow cancer cell growth; antidepressants and the risk of heart disease
10/19/01: New insights into autism; the wiley appendix
10/12/01: More bad news about obesity links to other diseases…Hey dad, can I borrow the car keys?
10/05/01: California leads nation in reduction of tobacco-related disease; exercise as an antidepressant?
09/25/01: Advances in the detection of breast cancer; primary care physician awareness of peripheral arterial disease; arsenic in the water
09/17/01: In perspective
09/12/01: Genes may hold secret to long life; men and women: cognitive function in the elderly; physical activity, obesity and the risk of pancreatic cancer
09/05/01: English milk cows prefer Beethoven and Simon & Garfunkel over Bananarama; new prostate cancer prevention study: looking for a few good men; exercise & diet can help prevent diabetes
08/28/01: Arthritis drugs may be linked with increased risk of heart disease; errors in blood clotting tests can be fatal; infant soy formula not associated with reproductive side effects

© 2002, Dr. Robert A. Wascher