Circadian disruption and biomarkers of tumor progression in breast cancer patients awaiting surgery.

Psychological distress, which can begin with cancer diagnosis and continue with treatment, is linked with circadian and endocrine disruption. In turn, circadian/endocrine factors are potent modulators of cancer progression. We hypothesized that circadian rest-activity rhythm disruption, distress, and diurnal cortisol rhythms would be associated with biomarkers of tumor progression in the peripheral blood of women awaiting breast cancer surgery. Breast cancer patients (n=43) provided actigraphic data on rest-activity rhythm, cancer-specific distress (IES, POMS), saliva samples for assessment of diurnal cortisol rhythm, cortisol awakening response (CAR), and diurnal mean. Ten potential markers of tumor progression were quantified in serum samples and grouped by exploratory factor analysis. Analyses yielded three factors, which appear to include biomarkers reflecting different aspects of tumor progression. Elevated factor scores indicate both high levels and strong clustering among serum signals. Factor 1 included VEGF, MMP-9, and TGF-ß; suggesting tumor invasion/immunosuppression. Factor 2 included IL-1ß, TNF-α, IL-6R, MCP-1; suggesting inflammation/chemotaxis. Factor 3 included IL-6, IL-12, IFN-γ; suggesting inflammation/TH1-type immunity. Hierarchical regressions adjusting age, stage and socioeconomic status examined associations of circadian, distress, and endocrine variables with these three factor scores. Patients with poor circadian coordination as measured by rest-activity rhythms had higher Factor 1 scores (R(2)=.160, p=.038). Patients with elevated CAR also had higher Factor 1 scores (R(2)=.293, p=.020). These relationships appeared to be driven largely by VEGF concentrations. Distress was not related to tumor-relevant biomarkers, and no other significant relationships emerged. Women with strong circadian activity rhythms showed less evidence of tumor promotion and/or progression as indicated by peripheral blood biomarkers. The study was not equipped to discern the cause of these associations. Circadian/endocrine aberrations may be a manifestation of systemic effects of aggressive tumors. Alternatively, these results raise the possibility that, among patients with active breast tumors, disruption of circadian activity rhythms and elevated CAR may facilitate tumor promotion and progression.

Psychoneuroimmune and endocrine pathways in cancer: effects of stress and support.

The bulk of cancer research has productively focused on the pathophysiology of the disease, emphasizing tumor biology, especially tumor characteristics such as DNA ploidy and estrogen/progesterone receptor status as predictors of disease outcome, at the expense of studying the body's psychophysiological reactions to tumor invasion. These reactions are mediated by brain/body mechanisms, including the endocrine, neuroimmune, and autonomic nervous systems. Although a large portion of the variance in any disease outcome is accounted for by the specific local pathophysiology of that disease, some variability must also be explained by 'host resistance' factors, which include the manner of response to the stress of the illness. The evidence of links between social support, stress, emotional state, and immune and endocrine function is growing. Here we examine evidence that 2 especially promising mechanisms, one immune, one endocrine, may mediate the relationship between stress and social support on the one hand and cancer progression on the other. We chose natural killer (NK) cells and cortisol because they are particularly good examples of mediating mechanisms for which there is solid basic and clinical evidence. NK cells are of great interest because they are involved in tumor surveillance, and because their activity can be measured in vitro.

Spiritual expression and immune status in women with metastatic breast cancer: an exploratory study.

This exploratory study examined relationships between spirituality and immune function in 112 women with metastatic breast cancer. Spirituality was assessed by patient reports of frequency of attendance at religious services and importance of religious or spiritual expression. White blood cell counts, absolute numbers of lymphocytes, T-lymphocyte subsets, and natural killer cells were assessed by flow cytometry. Assessments of natural killer cell activity and delayed-type hypersensitivity responses to skin test antigens provided two measures of functional immunity. In analyses controlling for demographic, disease status, and treatment variables, women who rated spiritual expression as more important had greater numbers of circulating white blood cells and total lymphocyte counts. Upon examination of relationships with lymphocyte subsets, both helper and cytotoxic T-cell counts were greater among women reporting greater spirituality.

Social support and salivary cortisol in women with metastatic breast cancer.

OBJECTIVE: This study used a cross-sectional design to examine the relationships between social support, both quantity (number of people) and quality (appraisal, belonging, tangible, and self-esteem), and neuroendocrine function (mean and slope of diurnal salivary cortisol) among women with metastatic breast cancer. METHODS: Participants (N = 103) were drawn from a study (N = 125) of the effects of group therapy on emotional adjustment and health in women with metastatic breast cancer. They completed the Interpersonal Support Evaluation List and the Yale Social Support Index and provided saliva samples for assessment of diurnal cortisol levels on each of 3 consecutive days. Diurnal mean levels were calculated using log-transformed cortisol concentrations, and the slope of diurnal cortisol variation was calculated by regression of log-transformed cortisol concentrations on sample collection time. RESULTS: Mean salivary cortisol was negatively related to the Interpersonal Support Evaluation List subscales of appraisal, belonging, and tangible social support. No association was found between quantitative support or the esteem subscale of the Interpersonal Support Evaluation List and mean salivary cortisol. Measures of qualitative and quantitative social support were not associated with the diurnal cortisol slope. CONCLUSIONS: Results show that greater quality of social support is associated with lower cortisol concentrations in women with metastatic breast cancer, which is indicative of healthier neuroendocrine functioning. These results may have clinical implications in the treatment of breast cancer.

Diurnal cortisol rhythm as a predictor of breast cancer survival.

BACKGROUND: : Abnormal circadian rhythms have been observed in patients with cancer, but the prognostic value of such alterations has not been confirmed. We examined the association between diurnal variation of salivary cortisol in patients with metastatic breast cancer and subsequent survival. We explored relationships between cortisol rhythms, circulating natural killer (NK) cell counts and activity, prognostic indicators, medical treatment, and psychosocial variables. METHODS: Salivary cortisol levels of 104 patients with metastatic breast cancer were assessed at study entry at 0800, 1200, 1700, and 2100 hours on each of 3 consecutive days, and the slope of diurnal cortisol variation was calculated using a regression of log-transformed cortisol concentrations on sample collection time. NK cell numbers were measured by flow cytometry, and NK cell activity was measured by the chromium release assay. The survival analysis was conducted by the Cox proportional hazards regression model with two-sided statistical testing. RESULTS: Cortisol slope predicted subsequent survival up to 7 years later. Earlier mortality occurred among patients with relatively "flat" rhythms, indicating a lack of normal diurnal variation (Cox proportional hazards, P =. 0036). Patients with chest metastases, as opposed to those with visceral or bone metastases, had more rhythmic cortisol profiles. Flattened profiles were linked with low counts and suppressed activity of NK cells. After adjustment for each of these and other factors, the cortisol slope remained a statistically significant, independent predictor of survival time. NK cell count emerged as a secondary predictor of survival. CONCLUSIONS: Patients with metastatic breast cancer whose diurnal cortisol rhythms were flattened or abnormal had earlier mortality. Suppression of NK cell count and NK function may be a mediator or a marker of more rapid disease progression.

Effects of psychosocial treatment in prolonging cancer survival may be mediated by neuroimmune pathways.

Research has provided growing evidence of links between the social environment and cancer progression. Indeed, social support in the form of marriage, frequent daily contact with others, and the presence of a confidant may all have protective value against cancer progression. Furthermore, retrospective data suggest that major stressful life events are more prevalent in patients with relapse or malignancy, and thus may contribute to cancer morbidity. Initial studies of the effects of psychosocial intervention with cancer patients have provided some promising results. In three randomized prospective trials, protective effects of psychosocial interventions on cancer progression have been confirmed, while one matching and one randomized study showed no survival effect after psychosocial treatment. Though more research is clearly needed in this area, this body of evidence suggests that psychosocial factors have potentially powerful modulating effects on the course of disease. Here we review evidence of one possible mechanism whereby psychosocial factors may influence disease-resistance capabilities: the neuroimmune connection. Suppressive effects of stress on immune function are well documented, and these effects have been shown to be modulated by social support. Thus, it is reasonable to hypothesize that supportive social relationships may buffer the effects of cancer-related stress on immunity, and thereby facilitate the recovery of immune mechanisms that may be important for cancer resistance. Data addressing this hypothesis are reviewed.

Effects of prenatal testosterone on sexual behavior, reproductive morphology and LH secretion in the female rat.

Sexual differentiation of many brain structures and functions is dependent on levels of testosterone (T) or its metabolites during certain 'sensitive' developmental periods. If T is present during these perinatal periods, masculinization and defeminization of sexual behavior occur; also, reproductive physiology, and central nervous system morphology and function are altered. The purpose of the present study was to characterize the influence of T at specific prenatal developmental intervals on offspring reproductive morphology, physiology, locomotor activity and sexual behavior during postnatal development. To avoid complications induced by endogenous testicular activity, only females were examined. Free T was used because of its relative short half-life, so that the effects induced by its administration on a specific gestational day (GD) could be evaluated. Pregnant rats received a single subcutaneous injection of either sesame oil (controls) or 5 mg of T on GD 16, 17, 18, 19, 20, 21, or 22. Female offspring of pregnant rats exposed to T displayed significant alterations in morphology and behavior. The anogenital distance, measured at 25 days postbirth, was significantly increased if T was administered on GD 16, 17 or 18. T treatment on GD 16 or each day thereafter through GD 20 significantly delayed the normal occurrence of vaginal opening (controls at 37.5 days vs. T treatment which ranged from 38.5 to 41.4 days). Abnormal vaginal morphology (enlarged clitoris) was also observed when T was injected during a similar prenatal interval (i.e. GD 16 to GD 22). Furthermore, prenatal T treatment on GD 18 (and each day thereafter), until GD 22 significantly decreased lordotic behavior compared to control values. However, exposure to T, on any prenatal GD did not alter the animals' ability to exhibit an induced luteinizing hormone (LH) surge. These results suggest that the onset for altered reproductive morphology occurs at least as early as GD 16, whereas the onset of sexual behavior sensitivity occurs precisely at GD 18, and that the normal pattern of adult LH release in females is not altered by prenatal androgen treatment using this specific paradigm.

Effects of exercise on insulin-induced hypoglycemia.

The purpose of this study was to determine the effect of exercise on the rate of onset of hypoglycemia induced by infusion of excess insulin (0.8 mU.min-1.100 g-1). Rats were either fasted overnight (FS) or fed ad libitum (FD). FS rats were killed after 5, 10, or 15 min of infusion at rest or after running on the treadmill at 21 m/min and 15% grade. FD rats were killed after 10, 20, or 40 min of infusion at rest or after exercise. Rats were also killed 15 min postexercise for FS and 60 or 120 min postexercise for FD with continued insulin infusion. The progressive decline in blood glucose was not altered by exercise in the FS rats. FD rats showed a significant difference due to exercise only after 40 min (rest 4.2 +/- 0.3 mM, exercise 3.2 +/- 0.2 mM). A significant postexercise repletion of glycogen was observed in red vastus and soleus muscles of FD rats despite the decreasing blood glucose values. These data indicate that exercise accelerates the rate of development of hypoglycemia in FD rats. In the FS rats, where the rate of decline in blood glucose was greater, exercise had no effect on the time course of development of hypoglycemia.