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Lutgendorf and Sood's team drew a connection between social support, stress hormones, and a factor called vascular endothelial growth factor, or VEGF, that supports tumor progression. VEGF helps a tumor increase its blood supply and higher levels of VEGF are related to poor survival in women with ovarian cancer.
The researchers found that women with ovarian cancer who reported higher levels of social support had lower levels of VEGF. In contrast, individuals who reported greater distress - feelings of helplessness or worthlessness - had higher VEGF levels.
"This was one of the first clinical findings in humans indicating that behavioral factors may not only be related to the immune response, but also to substances produced by tumors and surrounding cells that promote tumor progression," Lutgendorf said.
The scientists went further and treated two ovarian cancer cell lines with stress hormones, including norepinephrine and epinephrine, at levels similar to those produced by the body during times of stress. The researchers saw a profound increase in VEGF production by the cancer cell lines. Conversely, when they added propranolol, a drug that blocks these stress hormones, VEGF levels did
not increase.
The Iowa team has begun a larger prospective study to see if social support, distress, and VEGF levels are related to ovarian cancer recurrence. If this study supports earlier results, Lutgendorf envisions the use of behavioral interventions to reduce stress in patients in need. Further research may also lead to drugs that block the actions of stress hormones in cancer patients.
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