Genes could hold key to cure for breast cancer

From genetic testing to mammograms, breast cancer prevention has become a part of global oncology practice. In India, too, a few centres including the Adyar Cancer Institute in Chennai have started counselling healthy women who are genetically prone to breast cancer. The institute’s programme offers free genetic counselling for blood relatives of patients who are diagnosed with breast cancer. Starting with diet and exercise, the prevention program includes a mammogram, biopsy and elective surgery. For high-risk cases, oncologists do recommend removal of breasts before the onset of cancer. If women are disinclined towards breast removal, doctors suggest removing the ovaries, as they produce the hormone oestrogen, which is vital for the growth of new breast cancer cells. Removing ovaries, studies show, reduces the risk of breast cancer by nearly 50%. But more than intrusive procedures, doctors believe that lifestyle changes can also help prevent cancer. Studies have shown that reduced physical exercise, high-fat and low protein diet, smoking and alcoholism increase the risk of breast cancer. Other risk factors include delaying childbirth beyond 30 years and reduced breast feeding. “These factors have well-established links with breast cancer. And fortunately, women can do something about it to prevent or at least delay the onset of breast cancer,” said Dr T Rajkumar, head of molecular oncology, Cancer Research Institute. However, women have no control over other factors like early onset of the first menstrual cycle, late onset of menopause or their genetic makeup. Oncologists say that 10 to 15% of breast cancers are hereditary. Globally, scientists are trying t identify those genes that can cause cancer of the breast in people who don’t have a family history of the disease. Three years ago, the Adyar Cancer Institute studied 200 patients and 400 healthy women for mutations of a dozen genes associated with breast cancer. The study concluded that when there are mutations in three genes—TGFbeta1, P53, C-erB2—the risk of woman getting breast cancer increases nearly three times. But the institute admits that it has to screen more women and more genes to get a better picture. “So, as of now, we are able to help only those with hereditary risks,” Dr Rajkumar said. There is no vaccine or drug proven to prevent breast cancers. In some countries, as a trial, women are prescribed tamoxifen, which has the potential to reduce the chances of getting breast cancer by up to 80% as they starve the new cancer cells of oestrogen. Some doctors in India also prescribe this drug to high-risk, but otherwise healthy patients. This drug, though, comes with sideeffects that include sweating, fatigue and a slight increase in blood pressure. The more serious sideeffects can include joint pain due to osteoporosis and uterine cancer. Some doctors feel that the benefits outweigh the side effects. Tamoxifen is affordable, brings down the risk levels to less than 50% and is the only option available, they say. “Why should we ask women to wait or undergo surgeries when we know there is a drug that can help,” argued Delhibased Dr Puneet Gupta of the Indraprastha Apollo Hospitals. But the cancer institute’s Dr Rajkumar disagrees. “It’s disastrous if you prevent breast cancer and leave them (women) with uterine cancer,” he said. Breast cancer & prevention Genes that cause breast cancer Some of the genes identified are BRCA1 and BRCA2, P53, PTEN, STK11, MSH2 and MLH1. In some cases, changes in C-erbB2 and TGF Beta1 increases the risk threefold in cases where the disease is not hereditary. Mutations: Gene mutations can take place either when a person comes in contact with substances that cause cancer or when cells divide abnormally while copying the genetic code. When these abnormal cells and substances are not destroyed by the body’s immune system they accumulate and turn cancerous. Hereditary factor: Oncologists with the Adyar Cancer Institute in Chennai say that 10-15% of breast cancers are hereditary. According to doctors, you are at risk if more than two of your blood relatives have breast cancer. Early detection: Doctors advise aggressive screening for early detection, especially if the person has a family history of the disease. Screening includes self-examination, a clinical examination twice a year and annual ultrasound or mammogram. For high-risk cases, oncologists recommend removal of breasts before the onset of cancer. If a person is disinclined towards breast removal, doctors suggest removing the ovaries, as they produce the hormone oestrogen, which is vital for the growth of new breast cancer cells. Removing ovaries, studies show, reduces the risk of breast cancer by nearly 50%. Lifestyle matters More than intrusive procedures, doctors believe that lifestyle changes can help prevent breast cancer. Studies show that reduced physical exercise, a high-fat-lowprotein diet, smoking and alcoholism increase the risk. Other risk factors include delaying childbirth and reduced breast feeding. Is prevention the best answer? Preventive medicine has generated a controversy in the breast cancer world. Some specialists question the wisdom of giving medicines to healthy people, particularly a medication that has only been studied for a handful of years. “A person carrying the disease-causing gene does not necessarily get breast cancer. Studies show that 60% of them get the disease. Why give healthy people these drugs without knowing what the side-effects are, especially in the long term?” asked Mumbai-based oncologist Dr S H Advani.