Seasonal changes in serum melatonin in women with previous breast cancer

Chronometric Administration of Cyclophosphamide and a Double-Stranded DNA-Mix at Interstrand Crosslinks Repair Timing, Called "Karanahan" Therapy, Is Highly Efficient in a Weakly Immunogenic Lewis Carcinoma Model

Background and Aims: A new technology based on the chronometric administration of cyclophosphamide and complex composite double-stranded DNA-based compound, which is scheduled in strict dependence on interstrand crosslinks repair timing, and named “Karanahan”, has been developed. Being applied, this technology results in the eradication of tumor-initiating stem cells and full-scale apoptosis of committed tumor cells. In the present study, the efficacy of this novel approach has been estimated in the model of Lewis carcinoma.

Methods: To determine the basic indicative parameters for the approach, the duration of DNA repair in tumor cells, as well as their distribution along the cell cycle, have been assessed. Injections were done into one or both tumors in femoral region of the engrafted mice in accordance with the developed regimen. Four series of experiments were carried out at different periods of time. The content of poorly differentiated CD34⁺/TAMRA+ cells in the bone marrow and peripheral blood has been determined. Immunostaining followed by the flow cytometry was used to analyze the subpopulations of immune cells.

Results: The high antitumor efficacy of the new technology against the developed experimental Lewis carcinoma was shown. It was found that the therapy efficacy depended on the number of tumor growth sites, seasonal and annual peculiarities. In some experiments, a long-term remission has been reached in 70% of animals with a single tumor and in 60% with two tumors. In mice with two developed grafts, mobilization capabilities of both poorly differentiated hematopoietic cells of the host and tumor stem-like cells decrease significantly. Being applied, this new technology was shown to activate a specific immune response. There is an increase in the number of NK cell populations in the blood, tumor, and spleen, killer T cells and T helper cells in the tumor and spleen, CD11b+Ly-6C+ and CD11b+Ly-6G+ cells in the tumor. A population of mature dendritic cells is found in the tumor.

Conclusion: The performed experiments indicate the efficacy of the Karanahan approach against incurable Lewis carcinoma. Thus, the discussed therapy is a new approach for treating experimental neoplasms, which has a potential as a personalized anti-tumor therapeutic approach in humans.

Repercussions of melatonin on the risk of breast cancer: a systematic review and meta-analysis

SUMMARY Breast Cancer is common in women, but its etiology is not yet fully understood. Several factors may contribute to its genesis, such as genetics, lifestyle, and the environment. Melatonin may be involved in the process of breast cancer. Therefore, the aim of this study is to evaluate the influence of the levels of melatonin on breast cancer through a systematic review and meta-analysis. We performed a systematic review according to PRISMA recommendations. The primary databases MEDLINE, Embase, and Cochrane were consulted. There was no restriction on the year of publication and language. Data of systematic reviews from April 2017 to September to 2017 were analyzed. The meta-analysis was conducted using RevMan 5.3 software provided by the Cochrane Collaboration. From a total of 570 articles, 9 manuscripts were included in this review. They analy onzed women with breast cancer and control patients, of which 10% and 90% were in the reproductive period and after menopause, respectively. The lowest level of melatonin was found in approximately 55% of studies with breast cancer in post-menopause. The metanalyses of the studies demonstrated low levels of melatonin in breast cancer patients (n=963) compared with control patients (n= 1332), with a mean difference between the studies of −3.54 (CI −6.01, −1.06). Another difference found was in the comparison between smoking patients, with an average difference between 1.80 [0.97-2.63]. Our data suggest that low levels of melatonin might be a risk factor for breast cancer.

The association between birth weight, season of birth and latitude

BACKGROUND

Birth weight is known to fluctuate with month of birth and with latitude; however the mechanisms underlying these gradients remain unclear.

AIM

The study examined within-year fluctuations in birth weight across four regions in Australia.

SUBJECTS AND METHODS

We obtained the birth weight of singleton births of at least 37 weeks gestation from four regions: (a) southeast Queensland, (b) Sydney and surrounding districts, (c) Victoria, and (d) Tasmania. Seasonal fluctuations were examined after long-term trends had been removed. The amplitude, timing and variability of seasonal fluctuations were examined and compared across regions.

RESULTS

Each of the four regions had prominent annual periodicity with the peak birth weight occurring in spring. The amplitude of this signal ranged from 1.4 g (Victoria) to 7.7 g (southeast Queensland). There was no significant correlation between the amplitude of these fluctuations and the latitude of four regions. In addition, a second smaller autumn peak was identified.

CONCLUSION

Environmental factors that have regular within-year variation influence birth weight in Australia. The evidence suggests that at least two distinguishable seasonal processes contribute to the findings. Identifying the factors underlying these seasonal fluctuations could have implications from a public health perspective.

Low melatonin secretion associates with albedo in circumpolar environments

To clarify how seasonal changes of environmental luminosity affect melatonin secretion in human beings, nocturnal urine samples were collected every 2 months throughout the year from 20 outdoor workers living in an area, for which exact data on solar irradiance and temperature were available (67-68 degrees N). Melatonin secretion rates, determined by melatonin-specific radioimmunoassays, were found to be twice as high in December as in April, i.e. 0.88 +/- 0.16 nmol/12 hr (mean +/- S.E.) versus 0.43 +/- 0.09 nmol/12 hr, P < 0.05. Regression analyses showed that melatonin values correlated best inversely with solar irradiance reflected off the ground (albedo). A 10-fold increase in albedo for 1-4 weeks prior to the date of urine sampling was associated with a ca. 50% reduction in melatonin secretion. Association with global irradiance was weaker and did not correlate with temperature. Thus, light reaching the eyes via snow or other reflecting surfaces appears to be most effective. These results assist us in understanding some of the mechanisms involved in certain biological phenomena that exhibit seasonal variations as, for instance, reproduction and self-destructive behavior.

Predictability of monthly and yearly rhythms of breast cancer features

In order to evaluate if breast cancer biological characteristics undergo significant menstrual and seasonal variations, we analysed in a consecutive series of 905 breast cancer patients, steroid receptor level (ER and PgR by DCC assay), proliferative activity (3H-Thymidine Labeling Index, 3H-TLI) and size of primary tumour in relation to calendar date and day of menstrual cycle at the time of the surgical procedure. For data analysis, the method of time series construction and classical spectral analyses with Bartlett Kolmogorov-Smirnov test for white noise (BKS test) was utilised. For what concerns menstrual variations, 3H-TLI showed a significant periodicity (t = 0.3146, p < 0.01 by BKS test) with peaks at day 12nd and day 18th; ER showed a significant periodicity (t = 0.3605, p < 0.01 by BKS test) with more evident peak at day 27th; PgR, a significant periodicity (t = 0.160, p = 0.05 by BKS test) with peaks at day 15th and day 24th, similar to that observed for tumour size (t = 0.19, p < 0.05 by BKS test). With respect to yearly fluctuations, 3H-TLI showed only a trend for a significant rhythm (t = 0.16, p = 0.06 by BKS test) with peaks in May and November; ER a significant periodicity (t = 0.2099, p < 0.05 by BKS test) with two evident peaks in January and April; also for PgR a significant periodicity (t = 0.3161, p < 0.05 by BKS test) was demonstrated with a peak in July; finally, tumour size showed a significant rhythm (t = 0.335, p < 0.01) paralleling 3H-TLI behaviour. Finally, the analysis of variance with interaction of menstrual and seasonal timings showed that only the seasonal timing was able to independently influence the 3H-TLI variations (3H-TLI higher in spring). We confirmed that breast biology has significant menstrual and seasonal variations and that the seasonality is probably the timing factor more relevant in periodicity determination.

Melatonin, immune modulation and aging

Melatonin is a hormone secreted by the pineal gland in response to photoperiods and influences many important biological processes. For one, Melatonin has been shown to produce resistance to cancer and infectious diseases in aged animals. Studies in animals have demonstrated melatonin-related mechanisms of action on immunoregulation. Additionally, melatonin has been successfully used in humans, along with interleukin-2, as a treatment of solid tumors. In vivo and in vitro studies show melatonin enhances both natural and acquired immunity in animals. Despite all of this intriguing evidence, melatonin's mechanism of action on the immune system is only partially defined. It does, however, appear to act through lymphocyte receptors, and perhaps, receptors on other immune tissues, to modulate immune cells. In order to understand immunomodulation and anti-cancer effects, information on melatonin and it's interactions with other endocrine hormones are summarized.

Seasonal fluctuations in the cervical smear detection rates for (pre)malignant changes and for infections

The detection of diseases can exhibit seasonal fluctuations. This can be studied in cervical smears. Over a 9-year observation span (January 1983-January 1992) a series of 504,093 cervical smears obtained from a routine cytology laboratory in The Netherlands were examined for infections (monilia, trichomonas, actinomyces, human papilloma virus [HPV], chlamydia, and herpes) as well as for mild, moderate, and severe dysplasias, carcinoma in situ, and squamous carcinoma. Statistical analysis (principal component analysis) demonstrates clear seasonal rhythms in the detection of infections as well as in precursor lesions. These findings suggest that we are dealing with "true" detection rhythms. For the detection of (pre)malignancy and HPV, yearly fluctuations in women being screened might be the explanation for our observations.

The validity of melatonin as an oncostatic agent

The validity of melatonin as a prominent, naturally occurring oncostatic agent is examined in terms of its putative oncostatic mechanism of action, the correlation between melatonin levels and neoplastic activity, and the outcome of therapeutically administered melatonin in clinical trials. Melatonin's mechanism of action is summarized in a brief analysis of its actions at the cellular level, its antioxidative functions, and its indirect immunostimulatory effects. The difficulties of interpreting melatonin levels as a diagnostic or prognostic aid in cancer is illustrated by referral to breast cancer, the most frequently studied neoplasm in trials regarding melatonin. Trials in which melatonin was used therapeutically are reviewed, i.e., early studies using melatonin alone, trials of melatonin in combination with interleukin-2, and controlled studies comparing routine therapy to therapy in combination with melatonin. A table compiling the studies in which melatonin was used in the treatment of cancer in humans is presented according to the type of neoplasm. Melatonin's suitability in combination chemotherapy, where it augments the anticancer effect of other chemotherapeutic drugs while decreasing some of the toxic side effects, is described. Based on the evidence derived from melatonin's antiproliferative, antioxidative, and immunostimulatory mechanisms of action, from its abnormal levels in cancer patients and from clinical trials in which melatonin was administered, it is concluded that melatonin could indeed be considered a physiological anticancer substance. Further well-controlled trials should, however, be performed in order to find the link between its observed effects and the underlying mechanisms of action and to define its significance as a therapeutic oncostatic agent.

Seasonal variation in the secretion of mammotrophic hormones in normal women and women with previous breast cancer

Hormones such as melatonin whose serum concentrations vary seasonally have been previously implicated in the growth of breast cancer. The present study was undertaken to identify possible seasonal variation in a range of mammotrophic hormones which could exert a chronobiologic influence in women with breast tumours. Fifteen premenopausal women with a history of previous breast cancer (BC subjects) and 10 control women underwent 2-hourly serum sampling for 24 h at both summer and winter solstice for measurement of melatonin, growth hormone (GH), insulin-like growth factor-I (IGF-I), cortisol, prolactin and thyrotrophin (TSH). Hormone secretion at the different seasons was compared by measuring the area under the 24 h serum hormone concentration x time curves and by time series analysis of summer-to-winter differences in hormone concentration. Control women had significantly higher GH and IGF-I levels in summer compared to winter and significantly higher cortisol secretion in winter than summer. In contrast, BC women had no significant seasonal difference in IGF-I concentrations and had a reversal of the normal seasonal pattern of melatonin secretion, although seasonal changes in GH production were similar to controls. Prolactin and TSH showed no significant summer/winter variation in either group. Thus, seasonal variations in hormone secretion seen in normal women were, with exception of GH, absent or reversed in women with a previous history of breast cancer. As a result these individuals may be exposed to an asynchronous hormonal stimulus which could influence tumour growth. These changes could reflect a constitutional abnormality in BC women or may have been induced by the previous breast tumour.

Seasonal trends in the self-detection of breast cancer: indications from the Cancer and Steroid Hormone (CASH) study

Of 2895 women who self-detected an incident breast cancer that required surgery, peaks in month of detection occurred in spring and late autumn (p = 0.012). For the subset of cases for whom receptor status was available, there was a highly significant seasonal variation in detection only for those with ER-negative tumors. Further investigations into seasonality and breast cancer detection may be warranted.

Characteristics of the menstrual cycle at the time of surgery for breast cancer

Hormone measurements during the menstrual cycle were assessed in six premenopausal women undergoing breast cancer surgery and ten controls to determine whether the stress of diagnosis and surgery influenced cycle characteristics. There was hormonal evidence for normal ovulation in all cancer and control women, although the length of the luteal phase of the cycle was prolonged because of a delay in menstruation in two cancer patients. The timing of surgery in the cycle did not influence the hormonal data. The hormonal characteristics of the menstrual cycle thus appear to be normally preserved in women during the month in which breast cancer surgery is performed.

Acknowledging the weather-health link

The impact of weather on health is generally overlooked by physicians. Possible reasons for this include lack of training and insufficient awareness of the significant body of research on human biometeorology. The authors argue that, in the absence of clearly demonstrable causal connections, statistical associations between weather phenomena and health problems should be enough to influence clinical practice. Physicians in Germany make use of daily bulletins from the national weather service to advise patients on the management of common health problems that seem to be exacerbated by certain weather conditions. The authors urge Canadian doctors to follow the lead of their European colleagues by increasing their awareness of the relation between weather and health.