Roswell Park Comprehensive Cancer Center researchers announced this week that there is growing evidence women are more susceptible to lung cancer than men, particularly if they smoke.
It remains unclear, however, how sex hormones contribute to lung cancer in both men and women, regardless of their smoking status.
“Our findings suggest that smoking increases an individual’s cancer risk by disrupting important hormone pathways,” said Ting-Yuan “David” Cheng, assistant professor of oncology with the Roswell Park Cancer Prevention and Control team, who also holds a faculty appointment at the University of Florida. “Smoking cessation is therefore important for both women and men in order to preserve the integrity of hormone receptors.”
Cheng is first author of the study, “Smoking, Sex, and Non-Small Cell Lung Cancer: Steroid Hormone Receptors in Tumor Tissue.”
The study recently added support to the estrogen hypothesis of lung cancer development by identifying a link among smoking, sex, and hormones in patients with non-small cell lung cancer. The findings have been published online ahead of print in the Journal of the National Cancer Institute.
The research team collected tumor samples from 813 men and women with non-small cell lung cancer to try to identify the association between both smoking status and sex and the expression of different hormone receptors in the lung.
Researchers found that the expression of estrogen receptor beta, a hormone receptor known to inhibit tumor growth, was lower in women than in men, which supports the idea that women are more susceptible to lung cancer. Levels of this hormone receptor were particularly low in postmenopausal women and in those who had never used hormone therapy, suggesting that a decrease in the amount of circulating estrogen could be responsible. Other studies have suggested that expression of the estrogen receptor in small-cell lung cancer patients is lower in women than men, but the Roswell Park study is the first to confirm this sex difference.
The researchers also found that smoking influences hormone expression in both men and women. Lung tumors of smokers had higher levels of ER-α, which is known to promote tumor growth, than the tumors of nonsmokers. Smokers also tended to have lower expression of progesterone receptors, which contributes to a poorer prognosis, because progesterone can inhibit the growth of cancer cells.
The research team was led by Christine Ambrosone, chair of Roswell Cancer Prevention and Control, The work was supported in part by grants from the National Cancer Institute, the National Institute of Environmental Health Sciences and the Breast Cancer Research Foundation.