Breast cancer and circadian disruption from electric lighting in the modern world.

Breast cancer is the leading cause of cancer death among women worldwide, and there is only a limited explanation of why. Risk is highest in the most industrialized countries but also is rising rapidly in the developing world. Known risk factors account for only a portion of the incidence in the high-risk populations, and there has been considerable speculation and many false leads on other possibly major determinants of risk, such as dietary fat. A hallmark of industrialization is the increasing use of electricity to light the night, both within the home and without. It has only recently become clear that this evolutionarily new and, thereby, unnatural exposure can disrupt human circadian rhythmicity, of which three salient features are melatonin production, sleep, and the circadian clock. A convergence of research in cells, rodents, and humans suggests that the health consequences of circadian disruption may be substantial. An innovative experimental model has shown that light at night markedly increases the growth of human breast cancer xenografts in rats. In humans, the theory that light exposure at night increases breast cancer risk leads to specific predictions that are being tested epidemiologically: evidence has accumulated on risk in shift workers, risk in blind women, and the impact of sleep duration on risk. If electric light at night does explain a portion of the breast cancer burden, then there are practical interventions that can be implemented, including more selective use of light and the adoption of recent advances in lighting technology and application.

Fecal Microbiota Transplantation for Clostridium difficile Infection: A One-Center Experience.

BACKGROUND: Clostridium difficile is a gram-positive, anaerobic, and spore-forming bacillus, which is responsible for the majority of antibiotic-associated diarrhea and colitis. OBJECTIVE: Determine if fecal microbiota transplantation (FMT) is effective in a population sample from Connecticut. METHODS: We report the clinical experience of 92 consecutive patients from one gastroenterology practice in central Connecticut treated by colonoscopy with FMT for infection with Clostridium difficile from 2012 to 2017. The analyses are based on clinical follow-up up to 3 months after the FMT procedure and on medical chart review. RESULTS: Overall, complete recovery occurred in 86% of patients. As previously reported in a limited number of previous studies, community-acquired cases were more common than hospital-acquired cases, and community-acquired cases were more likely to be female. CONCLUSIONS: Consistent with some previous reports, we found the following: the source of the donor for FMT did not make a difference in recovery: material from nonrelatives was as effective as from close relatives; and the presence of multiple comorbidities did not make a difference in recovery: patients with 2 or more comorbidities did as well as those with one or none.

Rotating Night-Shift Work and the Risk of Breast Cancer in the Nurses' Health Studies.

In 2007, the International Agency for Research on Cancer declared shift work that involved circadian disruption to be a "probable" carcinogen (group 2A), noting that human evidence was limited. Using data from 2 prospective cohort studies, the Nurses' Health Study (1988-2012; n = 78,516) and Nurses' Health Study II (1989-2013; n = 114,559), we examined associations between rotating night-shift work and breast cancer risk. In the 2 cohorts, there were a total of 9,541 incident invasive breast malignancies and 24 years of follow-up. In the Nurses' Health Study, women with 30 years or more of shift work did not have a higher risk of breast cancer (hazard ratio (HR) = 0.95, 95% confidence interval (95% CI): 0.77, 1.17; P for trend = 0.63) compared with those who never did shift work, although follow-up occurred primarily after retirement from shift work. Among participants in the Nurses' Health Study II, who were younger than participants in the other cohort, the risk of breast cancer was significantly higher in women with 20 years or more of shift work at baseline, reflecting young-adult exposure (HR = 2.15, 95% CI: 1.23, 3.73; P for trend = 0.23), and was marginally significantly higher for women with 20 years or more of cumulative shift work when we used updated exposure information (HR = 1.40, 95% CI: 1.00, 1.97; P for trend = 0.74). In conclusion, long-term rotating night-shift work was associated with a higher risk of breast cancer, particularly among women who performed shift work during young adulthood. Further studies should explore the role of shift work timing on breast cancer risk.

Metformin Use in Practice: Compliance With Guidelines for Patients With Diabetes and Preserved Renal Function.

IN BRIEF Several contraindications limit the use of metformin, most notably the risk of lactic acidosis. This article reports on an examination of a population of patients with diabetes with preserved renal function to evaluate provider compliance with guidelines on metformin use and to identify factors that contributed when practice diverged from recommendations. It found that metformin was withheld from approximately one-third of these patients because of 1) an existent contraindication to metformin, 2) patient behavior or preference, or 3) provider preference or bias based on patient or personal factors. Although providers generally follow current recommendations for the use of metformin, deviations from guidelines in practice are common.

Colorectal polyp prevention by daily aspirin use is abrogated among active smokers.

PURPOSE: Based on suggestive findings from a recent study of high-risk Japanese patients, we sought to determine whether the risk of colorectal polyps associated with smoking may be modified by daily use of aspirin in an analysis of a large US screening population. METHODS: This is a cross-sectional study of 2,918 consecutive colonoscopy patients at a university hospital over a 30-month period. Data were abstracted from electronic medical records. Multivariate models of polyp counts were used to examine the competing risks of smoking and aspirin use. Models were further stratified by polyp location (proximal vs. distal) and pathologic subtype (dysplastic vs. serrated). RESULTS: Incidental rate of polyps was higher among active smokers [incidence rate ratio (IRR) 1.72; 95 % confidence interval (CI) 1.46-2.02] and lower among daily aspirin users (IRR 0.73; 95 % CI 0.61-0.86) compared to those who used neither. Smoking interacts significantly with aspirin use resulting in loss of aspirin protection (IRR 1.69; 95 % CI 1.28-2.24). Stratified analyses demonstrate that aspirin specifically reduces the risk of traditional dysplastic adenomas (IRR 0.72; 95 % CI 0.61-0.86) not serrated/hyperplastic polyps (IRR 0.92; 95 % CI 0.72-1.17) and that the modification of aspirin protection by smoking is primarily observed within the distal colorectum (p < 0.03). CONCLUSIONS: We report for the first time, in a typical risk US clinical population, a lack of protective association of aspirin for polyps among active smokers. Future prospective studies are recommended to confirm this mitigating effect in order to improve the precision of the growing evidence base about the chemopreventive benefit of aspirin in colorectal cancer.

Mortality risk from comorbidities independent of triple-negative breast cancer status: NCI-SEER-based cohort analysis.

PURPOSE: A comparatively high prevalence of comorbidities among African-American/Blacks (AA/B) has been implicated in disparate survival in breast cancer. There is a scarcity of data, however, if this effect persists when accounting for the adverse triple-negative breast cancer (TNBC) subtype which occurs at threefold the rate in AA/B compared to white breast cancer patients. METHODS: We reviewed charts of 214 white and 202 AA/B breast cancer patients in the NCI-SEER Connecticut Tumor Registry who were diagnosed in 2000-2007. We employed the Charlson Co-Morbidity Index (CCI), a weighted 17-item tool to predict risk of death in cancer populations. Cox survival analyses estimated hazard ratios (HRs) for all-cause mortality in relation to TNBC and CCI adjusting for clinicopathological factors. RESULTS: Among patients with SEER local stage, TNBC increased the risk of death (HR 2.18, 95 % CI 1.14-4.16), which was attenuated when the CCI score was added to the model (Adj. HR 1.50, 95 % CI 0.74-3.01). Conversely, the adverse impact of the CCI score persisted when controlling for TNBC (Adj. HR 1.49, 95 % CI 1.29-1.71; per one point increase). Similar patterns were observed in SEER regional stage, but estimated HRs were lower. AA/B patients with a CCI score of ≥3 had a significantly higher risk of death compared to AA/B patients without comorbidities (Adj. HR 5.65, 95 % CI 2.90-11.02). A lower and nonsignificant effect was observed for whites with a CCI of ≥3 (Adj. HR 1.90, 95 % CI 0.68-5.29). CONCLUSIONS: comorbidities at diagnosis increase risk of death independent of TNBC, and AA/B patients may be disproportionately at risk.

Aberrant methylation of miR-34b is associated with long-term shiftwork: a potential mechanism for increased breast cancer susceptibility.

PURPOSE: Although the evidence linking exposure to light at night (LAN) and breast cancer risk continues to accumulate, the molecular mechanisms driving this association remain to be fully elucidated. We have previously suggested that long-term exposure to LAN through shiftwork may result in dysregulated patterns of methylation genome-wide. In this study, we investigate the link between miR-34b, a miRNA suggested to be an important tumor suppressor, and shiftwork-related breast cancer. METHODS: Methylation states in the miR-34b promoter region were previously compared between 10 female long-term shiftworkers and 10 folate intake- and age-matched female dayworkers participating in the Danish "Diet, Cancer and Health" prospective cohort study. In order to further explore the functional role of miR-34b in breast tumorigenesis, a genome-wide expression microarray was carried out in miR-34b-overexpressed MCF-7 breast cancer cells and the identified transcripts were further analyzed for network and functional interrelatedness using Ingenuity Pathway Analysis software. RESULTS: We observed a 49.1 % increase in miR-34b promoter methylation among shiftworkers at a CpG site in this region (p = 0.016). Transfection of the miR-34b mimic in an MCF-7 breast cancer cell line induced differential expression of 230 transcripts that are involved in the interferon-mediated antiviral response as well as apoptotic and antiproliferative gene networks. CONCLUSIONS: Together, our results suggest that long-term shiftwork may increase the risk of breast cancer via methylation-based suppression of miR-34b and a consequent reduction in immunomediated anti-tumor capacity and support our previous findings that LAN may induce epigenetic alteration of cancer-relevant microRNAs.

Adverse events in cancer patients with sickle cell trait or disease: case reports.

PURPOSE: Given the relatively high prevalence of sickle cell trait and disease among African Americans and established racial disparities in cancer outcomes, we reviewed the literature regarding adverse events in cancer patients with these hematologic genotypes. Erythrocyte sickling can result from extreme hypoxia and other physiologic stressors, as might occur during cancer therapy. Further, tumoral hypoxia, a poor prognostic and predictive factor, could lead to a cycle of local sickling and increased hypoxia. METHODS: A search of PubMed produced 150 publications, most of which were excluded because of incidental relevance. Eleven case reports of patients diagnosed from 1993 to 2013 were reviewed. RESULTS: Two reports of patients with sickle cell trait describe an abundance of sickled erythrocytes within tumors, and a third report describes sickling-related events requiring multiday hospitalization. Eight reports of patients with sickle cell disease delineated multiorgan failure, vaso-occlusive crises, and rapid renal deterioration. Hypothesized triggers are delayed clearance of anticancer agents attributable to baseline kidney damage, activation of vasoadherent neutrophils from treatment to counter chemotherapy-induced neutropenia, hypoxia from general anesthesia, and intratumoral hypoxia. CONCLUSION: Clinical implications include pretreatment genotyping for prophylaxis, dose adjustment, and enhanced patient monitoring. With the current lack of high-quality evidence, however, the scope of poor outcomes remains unknown.

Baseline serum C-reactive protein and death from colorectal cancer in the NHANES III cohort.

Several prospective studies suggest that C-reactive protein (CRP), a nonspecific serologic marker of inflammation, might be linked to risk of colorectal cancer (CRC), whereas others have reported null or protective effects. We analyzed data from 7,072 participants (50-85 years) in the U.S. National Health and Nutrition Examination Survey III (1988-1994), a nationally representative cohort (n = 33,994; 2 months-85 years) with vital status follow-up to 2000. Hazard ratios (HRs) for mortality associated with baseline clinically raised (≥1.00 mg/dL) and intermediate (≥0.22-0.99 mg/dL) CRP levels were estimated using Cox proportional hazards regression controlling for CRC risk factors. There were 59 deaths from CRC, 106 from other obesity-related cancers (other-ORCs) and 1,130 from cardiovascular disease (CVD). Participants with clinically raised CRP at baseline were found to have a statistically significant greater risk of CRC death (HRs = 2.36-2.47) in comparison to persons with undetected levels. HRs were lower for death from other-ORC and CVD (1.82, 95% CI 1.05-3.15; 1.53, 95% CI 1.29-1.81, respectively). Intermediate CRP level was associated with a nonsignificant 10-21% increased risk for CRC death. HR for CRC death was higher among persons with a normal BMI (2.16, 95% 0.96-4.87, p = 0.06) compared to those who were overweight (1.22, 95% CI 0.53-2.78) or obese (1.23, 95% CI, 0.37-4.08). A similar pattern was observed for waist circumference. This effect modification suggests that the impact of chronic inflammation may be independent of excess body fat. Future research is recommended to confirm emerging data that elevated serologic CRP might reflect underlying colonic inflammation.

Invited commentary: validity of case-control studies of sleep duration and breast cancer.

The light-at-night theory of breast cancer causation states that a portion of the high breast cancer risk in the industrialized world, and of the rising risk in the developing word, is due to the introduction and increasing use of electricity to light the night. It is difficult to test this idea in human populations, partly because almost everyone in the modern world uses electric lighting after the sun sets. Specific hypotheses that have been tested include the notions that shift workers should be at higher risk, blind women should be at lower risk, and reported sleep duration should be inversely associated with risk. Girschik et al. (Am J Epidemiol. 2013;177(4):316-327) have tested the latter in a case-control study. Although the case-control design is useful for many questions, it is probably not useful for studies of sleep duration and health.

Genetic and epigenetic associations of circadian gene TIMELESS and breast cancer risk.

Results from recent molecular epidemiologic studies suggest that the core circadian genes play a role in breast tumorigenesis, possibly by influencing hormone regulation or other pathways relevant to cancer. In order to further evaluate this hypothesis, we conducted a genetic and epigenetic association study of the circadian regulator TIMELESS in breast carcinogenesis. We detected significant associations between two tagging SNPs (rs2291738 and rs7302060) in the TIMELESS gene and breast cancer among 441 breast cancer cases and 479 cancer-free controls, with apparent effect modification by ER/PR status. The presence of the C allele of rs7302060 was found to be associated with reduced breast cancer risk (OR, 0.54; 95% CI, 0.54-0.99). In addition, both the G/G genotype of rs2291738 and the C/C genotype of rs7302060 were associated with reduced risk of breast cancer among ER- or PR-positive breast cancer cases (OR, 0.46; 95% CI, 0.22-0.97 and OR, 0.36; 95% CI, 0.17-0.78, respectively). We also observed a significant association between stage II, III, and IV breast cancers and TIMELESS promoter hypomethylation in peripheral blood lymphocytes (OR, 0.35; 95% CI, 0.13-0.96) in 80 breast cancer cases and 80 age-matched controls, which is corroborated by documented overexpression of TIMELESS in breast tumor tissue compared to adjacent normal tissue. Our findings support the hypothesized role of circadian genes in breast tumorigenesis, and identify a set of circadian biomarkers for breast cancer susceptibility.

Body iron stores and breast cancer risk in female atomic bomb survivors.

Iron can be a potent pro-oxidant and, on this basis, elevated body iron may increase the risk of cancer. Although epidemiological evidence is mixed, there is overall support for this possibility. In addition, because of this same oxidative capacity, body iron levels may alter radiation sensitivity. In the present study, a nested case-control study of breast cancer was conducted in Japanese atomic bomb survivors. Stored serum samples from the Adult Health Study cohort were assayed for ferritin levels and joint statistical analyses were conducted of ferritin and radiation dose on the risk of breast cancer. Serum ferritin is the best feasible indicator of body iron levels in otherwise healthy people. A total of 107 cases and 212 controls were available for analysis. The relative risk (RR) of breast cancer for a 1 log unit increase in ferritin was 1.4 (95% confidence interval 1.1-1.8). This translates to an RR of 1.64 comparing high and low values of the interquartile range among controls (58 and 13.2 ng/mL, respectively). The results support the hypothesis that elevated body iron stores increase the risk of breast cancer. However, the study was inconclusive regarding the question of whether body iron alters radiation-induced breast cancer risk.

Night work and breast cancer risk among Norwegian nurses: assessment by different exposure metrics.

Associations between night work and breast cancer risk were investigated in a nested case-control study within a cohort of 49,402 Norwegian nurses. A total of 699 (74%) of the live cases diagnosed in 1990-2007 and 895 (65%) controls, cancer free at the time of sampling, were interviewed about work history and potential risk factors. The odds ratios for risk of breast cancer in relation to different exposure metrics were estimated by multivariate unconditional logistic regression models. No increase of risk was found after long duration of work by nurses working ≥3 night shifts per month. Small, nonsignificantly increased risks were observed for exposure to ≥30 years in hospitals or other institutions (odds ratio (OR) = 1.1), ≥12 years in schedules including night work (OR = 1.3), ≥1,007 night shifts during the lifetime (OR = 1.2), and lifetime average number of ≥4 night shifts per month (OR = 1.2). Nonsignificantly increased risks of breast cancer were observed in nurses who worked ≥5 years with ≥4 (OR = 1.4) and ≥5 (OR = 1.6) consecutive night shifts. Significantly increased risks were seen in nurses who worked ≥5 years with ≥6 consecutive night shifts (OR = 1.8, 95% confidence interval: 1.1, 2.8). The results suggest that risk may be related to number of consecutive night shifts.

Considerations of circadian impact for defining 'shift work' in cancer studies: IARC Working Group Report.

Based on the idea that electric light at night might account for a portion of the high and rising risk of breast cancer worldwide, it was predicted long ago that women working a non-day shift would be at higher risk compared with day-working women. This hypothesis has been extended more recently to prostate cancer. On the basis of limited human evidence and sufficient evidence in experimental animals, in 2007 the International Agency for Research on Cancer (IARC) classified 'shift work that involves circadian disruption' as a probable human carcinogen, group 2A. A limitation of the epidemiological studies carried out to date is in the definition of 'shift work.' IARC convened a workshop in April 2009 to consider how 'shift work' should be assessed and what domains of occupational history need to be quantified for more valid studies of shift work and cancer in the future. The working group identified several major domains of non-day shifts and shift schedules that should be captured in future studies: (1) shift system (start time of shift, number of hours per day, rotating or permanent, speed and direction of a rotating system, regular or irregular); (2) years on a particular non-day shift schedule (and cumulative exposure to the shift system over the subject's working life); and (3) shift intensity (time off between successive work days on the shift schedule). The group also recognised that for further domains to be identified, more research needs to be conducted on the impact of various shift schedules and routines on physiological and circadian rhythms of workers in real-world environments.

Nighttime light level co-distributes with breast cancer incidence worldwide.

Breast cancer incidence varies widely among countries of the world for largely unknown reasons. We investigated whether country-level light at night (LAN) is associated with incidence. We compared incidence rates of five common cancers in women (breast, lung, colorectal, larynx, and liver), observed in 164 countries of the world from the GLOBOCAN database, with population-weighted country-level LAN, and with several developmental and environmental indicators, including fertility rate, per capita income, percent of urban population, and electricity consumption. Two types of regression models were used in the analysis: Ordinary Least Squares and Spatial Errors. We found a significant positive association between population LAN level and incidence rates of breast cancer. There was no such an association between LAN level and colorectal, larynx, liver, and lung cancers. A sensitivity test, holding other variables at their average values, yielded a 30-50% higher risk of breast cancer in the highest LAN exposed countries compared to the lowest LAN exposed countries. The possibility that under-reporting from the registries in the low-resource, and also low-LAN, countries created a spurious association was evaluated in several ways and shown not to account for the results. These findings provide coherence of the previously reported case-control and cohort studies with the co-distribution of LAN and breast cancer in entire populations.

Phenotypic effects of the circadian gene Cryptochrome 2 on cancer-related pathways.

BACKGROUND: Circadian genes continue to gain attention as important transcriptional regulators with the potential to influence a variety of biological pathways, including many cancer-related processes. The core circadian gene cryptochrome 2 (CRY2) is essential for proper circadian timing, and is a key component of the negative arm of the circadian feedback loop. As such, aberrant expression of CRY2 may influence carcinogenic processes and thereby impact cancer susceptibility. METHODS: We silenced CRY2 in breast cancer cell lines (MCF-7) using small-interfering oligos (siRNA) and measured the impact of CRY2 knockdown on a number of cancer-relevant parameters. Cell cycle distribution, cell viability, and apoptotic response were measured in CRY2 knockdown (CRY2-) and normal (CRY2+) cell populations using flow cytometry in cells with and without exposure to a mutagen challenge. DNA damage accumulation was measured using the single cell gel electrophoresis (comet) assay, and damage was quantified using the Olive tail moment, which considers the amount and distance of DNA migration away from the nucleus, indicative of DNA strand breaks. Expression changes in cancer-relevant transcripts were measured by whole genome microarray. The Student's t-test was used for statistical comparisons, and P-values obtained from the microarray were adjusted for multiple comparisons using the false discovery rate correction, in order to obtain an adjusted Q-value for each observation. RESULTS: The comet assay results indicated that upon exposure to the same dose of chemical mutagen, CRY2- cells accumulate significantly more unrepaired DNA damage than CRY2+ cells (P = 0.040), suggesting that CRY2 may be important for DNA repair. In addition, a number of transcripts with relevance for DNA damage repair displayed altered expression following CRY2 silencing. These included BCCIP (Q = 0.002), BCL2 (Q = 0.049), CCND1 (Q = 0.009), CDKN1A (Q < 0.001), GADD45A (Q = 0.002), HERC5 (Q < 0.001), MCM5 (Q = 0.042), PPP1R15A (Q < 0.001), SUMO1 (Q < 0.001), and UBA1 (Q = 0.023). However, no significant influence of CRY2 knockdown on cell cycle distributions, cell cycle checkpoints in response to mutagen challenge, or apoptotic response was detected. CONCLUSIONS: In total, these data suggest a limited, but potentially important role for CRY2 in the regulation of DNA damage repair and the maintenance of genomic stability. Future investigations may focus on identifying the mechanisms by which CRY2 may regulate the expression of transcripts with known relevance for carcinogenesis.

Total visual blindness is protective against breast cancer.

OBJECTIVE: Observational data, though sparse and based on small studies with limited ability to control for known breast cancer risk factors, support a lower risk of breast cancer in blind women compared to sighted women. Mechanisms influenced by ocular light perception, such as melatonin or circadian synchronization, are thought to account for this lower risk. METHODS: To evaluate whether blind women with no perception of light (NPL) have a lower prevalence of breast cancer compared to blind women with light perception (LP), we surveyed a cohort of 1,392 blind women living in North America (66 breast cancer cases). RESULTS: In multivariate-logistic regression models controlling for breast cancer risk factors, women with NPL had a significantly lower prevalence of breast cancer than women with LP (odds ratio, 0.43; 95% confidence interval, 0.21-0.85). We observed little difference in these associations when restricting to postmenopausal women, non-shift workers or when excluding women diagnosed with breast cancer within 2 or 4 years of onset of blindness. Blind women with NPL appear to have a lower risk of breast cancer, compared to blind women with LP. More research is needed to elucidate the impact of LP on circadian coordination and melatonin production in the blind and how these factors may relate to breast cancer risk.

Number of aberrant crypt foci associated with adiposity and IGF1 bioavailability.

BACKGROUND: Dysregulation of the insulin-like growth factor (IGF) system, a common consequence of adiposity-induced insulin resistance, may be a key underlying mechanism linking excess body weight with colon cancer. Evidence has been derived from studies of cancer and polyps. Supporting data about aberrant crypt foci (ACF), putative pre-polyp changes, have been generated only from animal studies to date. METHODS: We randomly selected 26 patients with sex-specific elevated waist-hip-ratio (WHR) and 26 with normal values from a series of 150 patients seeking routine colonoscopy at the University of Connecticut Health Center. Cross-sectional analyses were performed of ACF number (<5, > or = 5) in relation to total IGF1, IGF-binding protein-3 (IGFBP3), insulin, body mass index (BMI), WHR and waist circumference (WC). Visualized ACF in the 20 cm of the distal colon were counted using advanced endoscopic imaging. RESULTS: Patients with > or = 5 ACF had higher BMI, WHR, and WC compared with patients with >5 ACF (p = 0.04, p = 0.03, and p = 0.01, respectively). IGFBP3 was reduced (p = 0.02) and IGF1:IGFBP3 molar ratio was greater (p = 0.03) in patients with > or = 5 ACF. We did not observe significant associations between ACF number and insulin or total IGF1. CONCLUSIONS: Our study provides the first report in humans of a possible association of ACF prevalence and IGF1 bioavailability as characterized by IGF1:IGFBP3 molar ratio and IGFBP3 level. More research is needed to determine whether this relationship is varied by ACF features (e.g., size, dysplasia, molecular changes), synchronous cancer and polyps, and is modified by colon cancer risk factors.

Electric light causes cancer? Surely you're joking, Mr. Stevens.

Night is no longer dark in the modern world, and the Milky Way has disappeared. Electric light has benefits but there are also a few detriments. These are (1) loss of the night sky, (2) wasted energy, (3) harm to animal and plant life, (4) and perhaps increases in some severe human maladies such as cancers of breast and prostate. The science on phototransduction for the circadian system and on clock gene function is evolving rapidly, and it provides a rationale for the idea that circadian disruption from light at night could cause disease. Direct evidence from humans and rodent models has also accumulated to the point where the idea is no longer fanciful. Although it may seem logical now, the journey on the path from electric light to breast cancer has been a tortuous one, at least for me.