BACKGROUND: The â2-adrenergic signaling pathway mediates the effects of chronic stress on ovarian cancer progression in mouse models. The relevance of this pathway to human ovarian cancer remains unknown.METHODS: We assessed tumor expression of â2-adrenergic receptor (ADRB2) using tissue microarrays in 237 ovarian cancer cases from the Nurses' Health Studies (NHS/NHSII). Competing risks Cox regression was used to evaluate whether associations of reproductive, hormonal, and psychosocial factors with ovarian cancer risk differed by ADRB2. We also examined the association between tumor ADRB2 expression and ovarian cancer survival.RESULTS: Forty-five (19%) cases were positive for ADRB2 staining. High levels of anxiety symptoms were positively associated with ADRB2-positive tumors (HR, 2.59; 95% confidence interval [CI], 1.15-5.84) but not with ADRB2-negative tumors (HR, 1.16; 95% CI, 0.81-1.66; Pheterogeneity = 0.07). We observed similar results for depression. No associations were observed for job strain, caregiving stress, or widowhood for either positive or negative ADRB2 status. Lifetime ovulatory years were more strongly associated with ADRB2-positive tumors (HR per 5 years, 1.60; 95% CI, 1.15-2.21) compared with ADRB2-negative tumors (HR, 1.11; 95% CI, 0.96-1.27; Pheterogeneity = 0.04). Significant heterogeneity by ADRB2 was also observed for parity (Pheterogeneity = 0.01), oral contraceptive use (Pheterogeneity = 0.03), and age at menopause (Pheterogeneity = 0.04). Tumor expression of ADRB2 was not associated with ovarian cancer mortality (HR, 1.05; 95% CI, 0.69-1.59).CONCLUSIONS: Several stress- and ovulation-related factors were differentially associated with ovarian tumors responsive to â2-adrenergic signaling.IMPACT: Replication in larger studies is warranted to confirm the role of â2-adrenergic signaling in ovarian cancer etiology. Cancer Epidemiol Biomarkers Prev; 25(12); 1587-94. ©2016 AACR.
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