Study: Cigarette Smoke Can Damage Normal Breast Cells (dateline August 31, 2006)
Cigarette smoke can prevent normal breast cells from repairing damage and lead to the development of cancer, according to researchers at the University of Florida. The link between smoking and breast cancer has been controversial. While tobacco contains cancer-causing agents and is known to increase the risk of lung cancer and other illnesses, research has been mixed as to whether smoking increases the risk of breast cancer.
To conduct the current study, lead researcher Satya Narayan, an associate professor of anatomy and cell biology at the University of Florida's College of Medicine, and colleagues exposed normal breast epithelial cells to cigarette smoke condensate-a tar derived from a machine that literally "smokes" a cigarette in the laboratory. They found that the breast cells were altered by the exposure and developed characteristics of cancerous breast cells.
"Our study suggests the mechanism by which this may be happening," said Narayan, in a University of Florida news release. "This is basically the important finding in our case: We are now describing how cigarette smoke condensate, which is a surrogate for cigarette smoke, can cause DNA damage and can block the DNA repair of a cell or compromise the DNA repair capacity of a cell. That can be detrimental for the cell and can lead to transformation or carcinogenesis."
The study, which is published in the journal Oncogene, shows that the body's process of DNA repair appears to be compromised when chemical components of smoke activate a key gene. According to the research, that gene interacts with an enzyme that plays a crucial role in repairing damaged DNA, preventing from repairing the cell, which has the ability to multiply rapidly.
"Its DNA repair machinery can be enhanced and it can fix the damaged DNA and restore genomic stability, or if the DNA repair machinery becomes compromised within the cell, then it can lead to an accumulation of mutations because the DNA is not fixed before the cell begins to divide," Narayan said. "The mutation then becomes a permanent part of the genome and causes genomic instability, and genomic instability can bring about several cellular dysfunctions, and one of them can lead to tumor formation."
The next phase of research will involve exploring ways to manipulate the DNA repair process and prevent the development of tumors. In the meantime, the researchers caution people, particularly teenagers, to not smoke. "Teenagers should realize they are inhaling 4,000 chemicals, and these chemicals can do so much harm in the body, not only posing a breast cancer risk but for so many other things," Narayan said. "The consequence of these chemicals is not apparent in one day or two days or in months; it takes years and years for cancers to develop. Once the gene is damaged and sitting there it's going to provide some harmful effect later on."
Researchers have been examining the possible link between smoking and breast cancer for years. In 2005, the California Air Resources Board's report found that secondhand smoke may increase the risk of breast cancer, particularly in pre-menopausal women. However, the report is controversial because some previous studies have not found an association between secondhand smoke and breast cancer.
Established risk factors for breast cancer include:
However, 80% of women who are diagnosed with breast cancer do not have any identifiable risk factors. Therefore, regular breast cancer screening can help detect the disease in its earliest stages when the chances of successful treatment and survival are the greatest.
Guidelines for early breast cancer detection: