While cigarette smoking’s link to cancer is well-known, the role of nicotine, a non-carcinogenic chemical found in tobacco, in breast-to-lung metastasis is an area where more research is needed. Now, scientists at Wake Forest School of Medicine have found that nicotine promotes the spread of breast cancer cells into the lungs.“Our data shows that nicotine exposure creates an environment in the lungs that is ripe for metastatic growth,” said Kounosuke Watabe, PhD, lead author of the study and professor of cancer biology. The study was published in January in the online edition of Nature Communications.
This environment, called a pre-metastatic niche, attracts pro-tumor neutrophils, a type of immune cells. The pre-metastatic niche releases a protein called STAT3-activated lipocalin 2 (LCN2) from the neutrophils to induce metastatic growth. For the study, Watabe’s team first studied 1,077 breast cancer patients and found that current smokers or former smokers have a higher incidence of lung metastasis compared to patients who never smoked.
Breast cancer is the second most common cancer among women in the United States, and cigarette smoking is associated with a higher incidence of breast cancer spread, or metastasis, lowering the survival rate by 33% at diagnosis.
In research published last year in the Journal of Experimental Medicine, Watabe’s team also found that nicotine promotes the spread of lung cancer cells into the brain. “Based on our findings, we don’t think that nicotine replacement products are the safest way for people with lung cancer to stop smoking,” he said.