Stress-Related Signaling Pathways in Lethal and Nonlethal Prostate Cancer

Recent data suggest that neuroendocrine signaling may influence progression in some cancers. We aimed to determine whether genes within the five major stress-related signaling pathways are differentially expressed in tumor tissue when comparing prostate cancer patients with lethal and nonlethal disease.

We measured mRNA expression of 51 selected genes involved in predetermined stress-related signaling pathways (adrenergic, glucocorticoid, dopaminergic, serotoninergic, and muscarinic systems) in tumor tissue and normal prostate tissue collected from prostate cancer patients in the Physicians' Health Study (n = 150; n = 82 with normal) and the Health Professionals Follow-Up Study (n = 254; n = 120 with normal). We assessed differences in pathway expression in relation to prostate cancer lethality as the primary outcome and to biomarkers as secondary outcomes.

Differential mRNA expression of genes within the adrenergic (P = 0.001), glucocorticoid (P < 0.0001), serotoninergic (P = 0.0019), and muscarinic (P = 0.0045) pathways in tumor tissue was associated with the risk of lethality. The adrenergic pathway was also statistically significant (P = 0.001) when comparing against differential expression of genes not involved in the pathways. In adjacent normal prostate tissue, none of the pathways was clearly differentially expressed between lethal and nonlethal prostate cancer. The glucocorticoid and adrenergic pathways were associated with cell proliferation, while the glucocorticoid pathway was additionally associated with angiogenesis and perineural invasion.

Our study suggests that stress-related signaling pathways, particularly the adrenergic and glucocorticoid, may be dysregulated in the tumors of men whose prostate cancer proves to be lethal, and motivates further investigation of these pathways in functional studies.