Obesity, weight gain, and ovarian cancer risk in African American women

Host obesity alters the ovarian tumor immune microenvironment and impacts response to standard of care chemotherapy

BACKGROUND

The majority of women with epithelial ovarian cancer (OvCa) are diagnosed with metastatic disease, resulting in a poor 5-year survival of 31%. Obesity is a recognized non-infectious pandemic that increases OvCa incidence, enhances metastatic success and reduces survival. We have previously demonstrated a link between obesity and OvCa metastatic success in a diet-induced obesity mouse model wherein a significantly enhanced tumor burden was associated with a decreased M1/M2 tumor-associated macrophage ratio (Liu Y et al. Can, Res. 2015; 75:5046-57).

METHODS

The objective of this study was to use pre-clinical murine models of diet-induced obesity to evaluate the effect of a high fat diet (HFD) on response to standard of care chemotherapy and to assess obesity-associated changes in the tumor microenvironment. Archived tumor tissues from ovarian cancer patients of defined body mass index (BMI) were also evaluated using multiplexed immunofluorescence analysis of immune markers.

RESULTS

We observed a significantly diminished response to standard of care paclitaxel/carboplatin chemotherapy in HFD mice relative to low fat diet (LFD) controls. A corresponding decrease in the M1/M2 macrophage ratio and enhanced tumor fibrosis were observed both in murine DIO studies and in human tumors from women with BMI > 30.

CONCLUSIONS

Our data suggest that the reported negative impact of obesity on OvCa patient survival may be due in part to the effect of the altered M1/M2 tumor-associated macrophage ratio and enhanced fibrosis on chemosensitivity. These data demonstrate a contribution of host obesity to ovarian tumor progression and therapeutic response and support future combination strategies targeting macrophage polarization and/or fibrosis in the obese host.

Metabolic dependencies and targets in ovarian cancer

Reprogramming of cellular metabolism is a hallmark of cancer. Cancer cells undergo metabolic adaptations to maintain tumorigenicity and survive under the attack of immune cells and chemotherapy in the tumor microenvironment. Metabolic alterations in ovarian cancer in part overlap with findings from other solid tumors and in part reflect unique traits. Altered metabolic pathways not only facilitate ovarian cancer cells' survival and proliferation but also endow them to metastasize, acquire resistance to chemotherapy, maintain cancer stem cell phenotype and escape the effects of anti-tumor immune defense. In this review, we comprehensively review the metabolic signatures of ovarian cancer and their impact on cancer initiation, progression, and resistance to treatment. We highlight novel therapeutic strategies targeting metabolic pathways under development.

Management of obesity across women's life course: FIGO Best Practice Advice

Obesity is a chronic, progressive, relapsing, and treatable multifactorial, neurobehavioral disease. According to the World Health Organization, obesity affects 15% of women and has long-term effects on women's health. The focus of care in patients with obesity should be on optimizing health outcomes rather than on weight loss. Appropriate and common language, considering cultural sensitivity and trauma-informed care, is needed to discuss obesity. Pregnancy is a time of significant physiological change. Pre-, ante-, and postpartum clinical encounters provide opportunities for health optimization for parents with obesity in terms of, but not limited to, fertility and breastfeeding. Pre-existing conditions may also be identified and managed. Beyond pregnancy, women with obesity are at an increased risk for gastrointestinal and liver diseases, impaired kidney function, obstructive sleep apnea, and venous thromboembolism. Gynecological and reproductive health of women living with obesity cannot be dismissed, with accommodations needed for preventive health screenings and consideration of increased risk for gynecologic malignancies. Mental wellness, specifically depression, should be screened and managed appropriately. Obesity is a complex condition and is increasing in prevalence with failure of public health interventions to achieve significant decrease. Future research efforts should focus on interprofessional care and discovering effective interventions for health optimization.

Racial differences in the association of body mass index and ovarian cancer risk in the OCWAA Consortium

BACKGROUND

Obesity disproportionately affects African American (AA) women and has been shown to increase ovarian cancer risk, with some suggestions that the association may differ by race.

METHODS

We evaluated body mass index (BMI) and invasive epithelial ovarian cancer (EOC) risk in a pooled study of case-control and nested case-control studies including AA and White women. We evaluated both young adult and recent BMI (within the last 5 years). Associations were estimated using multi-level and multinomial logistic regression models.

RESULTS

The sample included 1078 AA cases, 2582 AA controls, 3240 White cases and 9851 White controls. We observed a higher risk for the non-high-grade serous (NHGS) histotypes for AA women with obesity (ORBMI 30+= 1.62, 95% CI: 1.16, 2.26) and White women with obesity (ORBMI 30+= 1.20, 95% CI: 1.02, 2.42) compared to non-obese. Obesity was associated with higher NHGS risk in White women who never used HT (ORBMI 30+= 1.40, 95% CI: 1.08, 1.82). Higher NHGS ovarian cancer risk was observed for AA women who ever used HT (ORBMI 30+= 2.66, 95% CI: 1.15, 6.13), while in White women, there was an inverse association between recent BMI and risk of EOC and HGS in ever-HT users (EOC ORBMI 30+= 0.81, 95% CI: 0.69, 0.95, HGS ORBMI 30+= 0.73, 95% CI: 0.61, 0.88).

CONCLUSION

Obesity contributes to NHGS EOC risk in AA and White women, but risk across racial groups studied differs by HT use and histotype.

Leptin Protein Expression and Promoter Methylation in Ovarian Cancer: A Strong Prognostic Value with Theranostic Promises

Ovarian cancer (OC) is the deadliest among all gynecological cancers. Epidemiological studies showed that obesity might influence many cancers including OC. One of the key factors that may link obesity and OC is leptin (LEP), known as an adipokine with pleiotropic effects on body homeostasis. This study aims to investigate the expression pattern of LEP, assess the methylation profiles of LEP and their associations with clinicopathological features including survival outcomes of OC patients. The protein expression of LEP was evaluated in 208 samples using both tissue microarray and immunohistochemistry techniques. The methylation profiles of LEP were measured in 63 formalin-fixed, paraffin-embedded tumor tissues by quantitative polymerase chain reaction using a MethyLight assay. Our results showed a significant association of LEP protein overexpression with several clinicopathological variables, mainly tumor subtype, LVI, age of menarche, tumor size and stage (p < 0.04). Kaplan-Meier analysis (using low expression versus high expression as a discriminator) indicated that LEP protein overexpression is a powerful positive prognosticator of both OC recurrence (DFS) and disease-specific survival (DSS) in our OC cohort (log-rank p = 0.01 and p = 0.002, respectively). This implies that patients with high LEP expression profiles live longer with less recurrence rates. Methylation analysis results demonstrated a clear association between no/low LEP protein expression pattern (38%) and LEP promoter CpG island hypermethylation (43%). Results of this study suggest that LEP is a powerful prognosticator of OC recurrence and DSS. LEP expression in OC seems to be regulated by its promoter hypermethylation through gene partial/total silencing. Further multi-institutional studies using larger cohorts are required to demystify the intricate molecular functions of this leptin-driven effects in OC pathophysiology and to accurately assess its theranostic potential and validate its prognostic/predictive power in OC onset, progression towards more effective and personalized management of OC patients.

Disease Burden and Attributable Risk Factors of Ovarian Cancer From 1990 to 2017: Findings From the Global Burden of Disease Study 2017

Aim: We aimed to estimate the disease burden and risk factors attributable to ovarian cancer, and epidemiological trends at global, regional, and national levels.

Methods: We described ovarian cancer data on incidence, mortality, and disability-adjusted life-years as well as age-standardized rates from 1990 to 2017 from the Global Health Data Exchange database. We also estimated the risk factors attributable to ovarian cancer deaths and disability-adjusted life-years. Measures were stratified by region, country, age, and socio-demographic index. The estimated annual percentage changes and age-standardized rates were calculated to evaluate temporal trends.

Results: Globally, ovarian cancer incident, death cases, and disability-adjusted life-years increased by 88.01, 84.20, and 78.00%, respectively. However, all the corresponding age-standardized rates showed downward trends with an estimated annual percentage change of −0.10 (−0.03 to 0.16), −0.33 (−0.38 to −0.27), and −0.38 (−0.32 to 0.25), respectively. South and East Asia and Western Europe carried the heaviest disease burden. The highest incidence, deaths, and disability-adjusted life-years were mainly in people aged 50–69 years from 1990 to 2017. High fasting plasma glucose level was the greatest contributor in age-standardized disability-adjusted life-years rate globally as well as in all socio-demographic index quintiles and most Global Disease Burden regions. Other important factors were high body mass index and occupational exposure to asbestos.

Conclusion: Our study provides valuable information on patterns and trends of disease burden and risk factors attributable to ovarian cancer across age, socio-demographic index, region, and country, which may help improve the rational allocation of health resources as well as inform health policies.

A Review of Research on Disparities in the Care of Black and White Patients With Cancer in Detroit

Racial disparities in cancer incidence and outcomes are well-documented in the US, with Black people having higher incidence rates and worse outcomes than White people. In this review, we present a summary of almost 30 years of research conducted by investigators at the Karmanos Cancer Institute's (KCI's) Population Studies and Disparities Research (PSDR) Program focusing on Black-White disparities in cancer incidence, care, and outcomes. The studies in the review focus on individuals diagnosed with cancer from the Detroit Metropolitan area, but also includes individuals included in national databases. Using an organizational framework of three generations of studies on racial disparities, this review describes racial disparities by primary cancer site, disparities associated with the presence or absence of comorbid medical conditions, disparities in treatment, and disparities in physician-patient communication, all of which contribute to poorer outcomes for Black cancer patients. While socio-demographic and clinical differences account for some of the noted disparities, further work is needed to unravel the influence of systemic effects of racism against Black people, which is argued to be the major contributor to disparate outcomes between Black and White patients with cancer. This review highlights evidence-based strategies that have the potential to help mitigate disparities, improve care for vulnerable populations, and build an equitable healthcare system. Lessons learned can also inform a more equitable response to other health conditions and crises.

Invited Commentary: Relationship Between Ovulation and Markers of Systemic Inflammation Versus Markers of Localized Inflammation

In this issue of the American Journal of Epidemiology, Huang et al. (Am J Epidemiol. 2020;189(7):660-670) report an inverse relationship between lifetime ovulatory years (LOY) and circulating levels of C-reactive protein (CRP), counter to their hypothesis. CRP is a nonspecific systemic marker of chronic inflammation, and there is evidence that there are other drivers of systemic inflammation as measured by CRP. There also is a body of evidence supporting the possibility that ovulation may be responsible for a localized inflammatory response. Because ovarian cancer is the fifth most common cause of cancer death in women, preventive strategies are urgently needed. The findings of this report underscore the need for new research initiatives to determine the relationship between incessant ovulation and ovarian cancer risk in order to identify mechanisms of carcinogenesis.

African American women with advanced-stage ovarian cancer have worse outcomes regardless of treatment type

OBJECTIVE

There has been an increase in the use of neoadjuvant chemotherapy in recent years. Our objective was to determine if African American women are more likely to receive neoadjuvant chemotherapy than primary debulking surgery, when compared to their Caucasian counterparts, and the impact of such an approach on oncologic outcomes.

METHODS

A retrospective cohort study was performed using the National Cancer Database (NCDB). Women aged 18-90 years, diagnosed with stage IIIC or IV epithelial ovarian cancer between January 2010 through December 2014 were included. Women with unknown treatment or treatments outside of neoadjuvant chemotherapy or primary debulking surgery were excluded. Only women of Caucasian, African American, or Hispanic origin who received either neoadjuvant chemotherapy or primary debulking surgery were included; all other races were excluded. Descriptive statistics were computed, and continuous variables were assessed for normality. Groups were compared using ANOVA or non-parametric medians tests for continuous variables, and chi-squared tests were used for dichotomous or categorical variables. Logistic regression was used to identify predictors of treatment. A p value of 0.05 was considered statistically significant.

RESULTS

A total of 19 838 women with stage IIIC and IV epithelial ovarian cancer met the inclusion criteria. A total of 14 988 (75.6%) were treated with primary debulking surgery, while 4850 women (24.4%) were treated with neoadjuvant chemotherapy. Of those treated with neoadjuvant chemotherapy, 24.5% were white, 27.0% were African American, and 22.1% were Hispanic (p=0.005), and when adjusted for confounders, being African American was a predictor of receiving neoadjuvant chemotherapy (adjusted odds ratio (aOR) 1.29, 95% CI 1.10 to 1.51). Ninety-day mortality rates were higher in African American women compared with Caucasian and Hispanic women (2.9% vs 2.0% vs 1.6%, p=0.013). There were no differences in 30-day mortality, 90-day mortality, or status at last contact in African American women, when comparing neoadjuvant chemotherapy and primary debulking surgery. In Caucasian women, outcomes were worse in women receiving neoadjuvant chemotherapy.

CONCLUSIONS

Compared to other races, African American women with advanced ovarian cancer are more likely to receive neoadjuvant chemotherapy than primary debulking surgery and had a higher 90-day mortality rate. In African American women there was no difference in outcomes based on treatment type.

Ovarian Cancer in Women of African Ancestry (OCWAA) consortium: a resource of harmonized data from eight epidemiologic studies of African American and white women

PURPOSE

Although the incidence rate of epithelial ovarian cancer (EOC) is somewhat lower in African American (AA) than white women, survival is worse. The Ovarian Cancer in Women of African Ancestry (OCWAA) consortium will overcome small, study-specific sample sizes to better understand racial differences in EOC risk and outcomes.

METHODS

We harmonized risk factors and prognostic characteristics from eight U.S.

STUDIES

the North Carolina Ovarian Cancer Study (NCOCS), the Los Angeles County Ovarian Cancer Study (LACOCS), the African American Cancer Epidemiology Study (AACES), the Cook County Case-Control Study (CCCCS), the Black Women's Health Study (BWHS), the Women's Health Initiative (WHI), the Multiethnic Cohort Study (MEC), and the Southern Community Cohort Study (SCCS).

RESULTS

Determinants of disparities for risk and survival in 1,146 AA EOC cases and 2,922 AA controls will be compared to 3,368 white EOC cases and 10,270 white controls. Analyses include estimation of population-attributable risk percent (PAR%) by race.

CONCLUSION

OCWAA is uniquely positioned to study the epidemiology of EOC in AA women compared with white women to address disparities. Studies of EOC have been underpowered to address factors that may explain AA-white differences in the incidence and survival. OCWAA promises to provide novel insight into disparities in ovarian cancer.

Obesity and Risk for Second Malignant Neoplasms in Childhood Cancer Survivors: A Case-Control Study Utilizing the California Cancer Registry

BACKGROUND

Obesity is a known modifiable risk factor associated with adverse outcomes in children with cancer. We sought to determine whether obesity during childhood cancer treatment increases risk for second malignant neoplasms (SMN).

METHODS

In this case-control study, cases (with SMN) and controls (with a single-primary cancer) were selected from the California Cancer Registry who had primary cancer diagnosed <21 years treated at Children's Hospital Los Angeles between 1988 and 2014. Controls were matched 3:1 to cases at the registry level by clinical factors. Medical records were abstracted for cancer treatment exposures, cancer predisposition syndrome, body mass index (BMI), BMI Z-score, and BMI category at diagnosis and end of therapy (EOT).

RESULTS

A total of 59 cases and 130 controls were included. Median age at primary cancer diagnosis was 6 years, 64.5% were male, median time from primary cancer to SMN was 7.5 years, and 31.7% were obese or overweight. In matched multivariable analyses, there were elevated but nonsignificant associations between SMN and higher BMI Z-score at diagnosis [OR 1.27 (0.99-1.63)] and higher BMI categories at diagnosis [adjusted OR (aOR) overweight, 1.25 (0.55-2.52); aOR obese, 2.51 (1.00-6.29)]. There was a significantly increased risk for SMN among patients who were obese at both diagnosis and EOT [aOR, 4.44 (1.37-14.34)].

CONCLUSIONS

This study suggests that obesity during childhood cancer treatment may be associated with increased risk for SMNs, particularly among those obese throughout therapy.

IMPACT

Additional studies to confirm these findings and to develop interventions have the potential to impact SMN development in children with cancer.

Evaluation of vitamin D biosynthesis and pathway target genes reveals UGT2A1/2 and EGFR polymorphisms associated with epithelial ovarian cancer in African American Women

An association between genetic variants in the vitamin D receptor (VDR) gene and epithelial ovarian cancer (EOC) was previously reported in women of African ancestry (AA). We sought to examine associations between genetic variants in VDR and additional genes from vitamin D biosynthesis and pathway targets (EGFR, UGT1A, UGT2A1/2, UGT2B, CYP3A4/5, CYP2R1, CYP27B1, CYP24A1, CYP11A1, and GC). Genotyping was performed using the custom-designed 533,631 SNP Illumina OncoArray with imputation to the 1,000 Genomes Phase 3 v5 reference set in 755 EOC cases, including 537 high-grade serous (HGSOC), and 1,235 controls. All subjects are of African ancestry (AA). Logistic regression was performed to estimate odds ratios (OR) and 95% confidence intervals (CI). We further evaluated statistical significance of selected SNPs using the Bayesian False Discovery Probability (BFDP). A significant association with EOC was identified in the UGT2A1/2 region for the SNP rs10017134 (per allele OR = 1.4, 95% CI = 1.2-1.7, P = 1.2 × 10-6 , BFDP = 0.02); and an association with HGSOC was identified in the EGFR region for the SNP rs114972508 (per allele OR = 2.3, 95% CI = 1.6-3.4, P = 1.6 × 10-5 , BFDP = 0.29) and in the UGT2A1/2 region again for rs1017134 (per allele OR = 1.4, 95% CI = 1.2-1.7, P = 2.3 × 10-5 , BFDP = 0.23). Genetic variants in the EGFR and UGT2A1/2 may increase susceptibility of EOC in AA women. Future studies to validate these findings are warranted. Alterations in EGFR and UGT2A1/2 could perturb enzyme efficacy, proliferation in ovaries, impact and mark susceptibility to EOC.

A review of the effects of healthcare disparities on the experience and survival of ovarian cancer patients of different racial and ethnic backgrounds

Ovarian cancer (OC) is a serious condition that often presents at advanced stages and has high mortality rates, with the current mode of early-stage screening lacking sensitivity and specificity. OC often presents asymptomatically, which renders early diagnosis difficult. Furthermore, many patients lack significant risk factors or family history of the disease. Five-year survival rates differ between patients with OC among racial, ethnic, and social groups as a result of different social barriers. This review article aims to present the currently existing data regarding health care disparities among OC patients of different ethnic, demographic, and socioeconomic backgrounds, and what next steps should be taken to better understand and eventually eliminate these potentially devastating health care disparities. Increasing data support the notion that a combination of genomic, socioeconomic status, social factors, and cultural differences lead to differential treatments and therefore health care disparities. While genomic and biological factors are important, language barriers, geographic and travel barriers, differences in comorbidity likelihood between populations, and different treatment plans seem to have a greater impact on 5-year survival rates of patients from diverse backgrounds. Language barriers limit a shared-decision model of care. Transportation limitations and geographic differences can lead to limited follow-up and insufficient care in resource and equipment restrictive settings. Patients with these barriers also tend to have a higher incidence of comorbidities that raise the mortality rate of OC. Further research needs to explore effective solutions to bridge health care disparities and understand why they occur.

Anaplastic carcinoma in ovarian seromucinous cystic tumor of borderline malignancy

Background

The mortality rate of ovarian cancer is the highest among all gynecological malignancies in Japan. Ovarian tumors are classified as benign, borderline malignant, or malignant. Anticipating the histological subtype with imaging only is often difficult because of several histological subtypes of epithelial ovarian tumors (such as serous, mucinous, endometrioid, clear cell, and Brenner tumors). In addition, the majority of mucinous tumors in the ovary are metastatic. Furthermore, mucinous tumors belong to one of the two different subclasses (i.e., intestinal and seromucinous types). Ovarian seromucinous cystic tumors of borderline malignancy are infrequent and only rarely coexist with other malignant tumors.

Case presentation

We have reported a 53-year-old Japanese woman with anaplastic carcinoma in an ovarian seromucinous cystic tumor of borderline malignancy. Her MRI and CT analysis revealed an ovarian tumor with a mural nodule, ascites, and peritoneal dissemination. Enhanced MRI revealed that the mural nodule was enhanced. Enhanced CT analysis revealed that the lymph nodes were not swollen. Intriguingly, the mural nodule crossed the cyst wall into the cavity and onto the surface. Her laboratory data revealed high serum CA 125 level. Cumulatively, these results suggested ovarian malignancy. The patient underwent hysterectomy with bilateral salpingo-oophorectomy, omentectomy, and resection of the disseminated lesions. Lymph node biopsy was omitted because of the suggestion of enhanced CT image findings and palpation during surgery. Her postoperative specimen examination determined FIGO at least stage IIIB, and accordingly, adjuvant chemotherapy was prescribed. After 3 years of the operation, the patient is presently alive without clinical tumor recurrences.

Conclusion

Imaging studies with pathognomonic findings contributed to ovarian cancer diagnosis in this case. To the best of our knowledge, this is the first study in English literature to report detailed classification of mucinous borderline malignancy, seromucinous cystic, and anaplastic carcinoma in an ovarian seromucinous cystic tumor of borderline malignancy.

Anthropometric characteristics and ovarian cancer risk and survival

PURPOSE

Multiple studies have examined the role of anthropometric characteristics in ovarian cancer risk and survival; however, their results have been conflicting. We investigated the associations between weight change, height and height change and risk and outcome of ovarian cancer using data from a large population-based case-control study.

METHODS

Data from 699 ovarian cancer cases and 1,802 controls who participated in the HOPE study were included. We used unconditional logistic regression adjusted for age, race, number of pregnancies, use of oral contraceptives, and family history of breast or ovarian cancer to examine the associations between self-reported height and weight and height change with ovarian cancer risk. Cox proportional hazards regression models adjusted for age and stage were used to examine the association between the exposure variables and overall and progression-free survival among ovarian cancer cases.

RESULTS

We observed an increased risk of ovarian cancer mortality and progression for gaining more than 20 pounds between ages 18-30, HR 1.36; 95% CI 1.05-1.76, and HR 1.31; 95% CI 1.04-1.66, respectively. Losing weight and gaining it back multiple times was inversely associated with both ovarian cancer risk, OR 0.78; 95% CI 0.63-0.97 for 1-4 times and OR 0.73; 95% CI 0.54-0.99 for 5-9 times, and mortality, HR 0.63; 95% CI 0.40-0.99 for 10-14 times. Finally, being taller during adolescence and adulthood was associated with increased risk of mortality. Taller stature and weight gain over lifetime were not related to ovarian cancer risk.

CONCLUSIONS

Our results suggest that height and weight and their change over time may influence ovarian cancer risk and survival. These findings suggest that biological mechanisms underlying these associations may be hormone driven and may play an important role in relation to ovarian carcinogenesis and tumor progression.

Current Gaps in Ovarian Cancer Epidemiology: The Need for New Population-Based Research

With recent ovarian cancer screening studies showing no clinically significant mortality benefit, preventing this disease, identifying high-risk populations, and extending survival remain priorities. However, several challenges are impeding progress in ovarian cancer research. With most studies capturing exposure information from 10 or more years ago, evaluation of how changing patterns of exposures, such as new oral contraceptive formulations and increased intrauterine device use, might influence ovarian cancer risk and survival is difficult. Risk factors for ovarian cancer should be evaluated in the context of tumor histotypes, which have unique molecular features and cells of origin; this is a task that requires large collaborative studies to achieve meaningful sample sizes. Importantly, identification of novel modifiable risk factors, in addition to those currently known to reduce risk (eg, childbearing, tubal ligation, oral contraceptive use), is needed; this is not feasibly implemented at a population level. In this Commentary, we describe important gaps in knowledge and propose new approaches to advance epidemiologic research to improve ovarian cancer prevention and survival, including updated classification of tumors, collection of data on changing and novel exposures, longer follow-up on existing studies, evaluation of diverse populations, development of better risk prediction models, and collaborating prospectively with consortia to develop protocols for new studies that will allow seamless integration for future pooled analyses.

Racial health disparities in ovarian cancer: not just black and white

Ovarian cancer (OC) is the most lethal gynecological malignancy, which disproportionately affects African American (AA) women. Lack of awareness and socioeconomic factors are considered important players in OC racial health disparity, while at the same time, some recent studies have brought focus on the genetic basis of disparity as well. Differential polymorphisms, mutations and expressions of genes have been reported in OC patients of diverse racial and ethnic backgrounds. Combined, it appears that neither genetic nor the socioeconomic factors alone might explain the observed racially disparate health outcomes among OC patients. Rather, a more logical explanation would be the one that takes into consideration the combination and/or the interplay of these factors, perhaps even including some environmental ones. Hence, in this article, we attempt to review the available information on OC racial health disparity, and provide an overview of socioeconomic, environmental and genetic factors, as well as the epigenetic changes that can act as a liaison between the three. A better understanding of these underlying causes will help further research on effective cancer management among diverse patient population and ultimately narrow health disparity gaps.

Tubal ligation and ovarian cancer risk in African American women

PURPOSE

Tubal ligation has been associated with reduced risk of epithelial ovarian cancer (EOC) in studies of primarily white women, but less is known about the association in African American (AA) women. We sought to evaluate the associations among 597 invasive ovarian cancer cases and 742 controls of AA descent recruited from the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US.

METHODS

Multivariable logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potentially confounding factors.

RESULTS

An inverse association between tubal ligation and EOC was observed that was not statistically significant (OR 0.88, 95% CI 0.68-1.14). However, an inverse association with EOC risk was observed among women who had a tubal ligation at age 35 years or older (OR 0.64; 95% CI 0.41-0.98), but not among those who had a tubal ligation before age 35 (OR 0.98; 95% CI 0.74-1.29) (p for interaction = 0.08). The association also varied considerably by tumor subtype. A strong inverse association was observed for endometrioid tumors (OR 0.31, 95% CI 0.14-0.70), whereas associations with mucinous (OR 0.87, 95% CI 0.36-2.12) and serous (OR 0.94, 95% CI 0.71-1.24) tumors were weaker and not statistically significant. A statistically non-significant positive association for clear cell tumors (OR 1.84, 95% CI 0.58-5.82) was based on a low number of cases.

CONCLUSIONS

Our findings show that tubal ligation may confer a reduced risk for EOC among AA women that is comparable to the associations that have been previously observed in primarily white populations.

Obesity and ovarian cancer risk: A systematic review

The association between obesity and ovarian cancer risk has been extensively investigated, but studies have yielded inconsistent findings. This review aims to summarise and discuss the evidence generated to date. Articles published in English prior to August 2016 were retrieved from PubMed. Keywords included obesity, overweight, body size, body mass index, waist-hip ratio, waist circumference, body weight, ovarian cancer, ovarian carcinoma, ovarian neoplasm, and ovarian tumour. Eligible studies compared two or more groups of women, with at least one group in the overweight or obese category and one comprising normal weight controls. Summary data in the form of relative risk, hazard ratio, or odds ratio for each comparison group from individual studies were collated and reviewed. Forty-three studies were included in the final analysis, with a total of 3,491,943 participants. All studies included body mass index as an exposure measure, and a majority relied on self-reported measures from participants; 14 studies found a statistically significant positive association between ovarian cancer risk and higher body mass index, 26 studies found no significant association, and 3 studies found a negative association between ovarian cancer risk and higher body mass index. This review concludes that there is limited, inconsistent evidence of a positive association between obesity and ovarian cancer risk.

Cholesterol Synthetase DHCR24 Induced by Insulin Aggravates Cancer Invasion and Progesterone Resistance in Endometrial Carcinoma

3β-Hydroxysteroid-Δ24 reductase (DHCR24), the final enzyme of the cholesterol biosynthetic pathway, has been associated with urogenital neoplasms. However, the function of DHCR24 in endometrial cancer (EC) remains largely elusive. Here, we analyzed the expression profile of DHCR24 and the progesterone receptor (PGR) in our tissue microarray of EC (n = 258), the existing EC database in GEO (Gene Expression Omnibus), and TCGA (The Cancer Genome Atlas). We found that DHCR24 was significantly elevated in patients with EC, and that the up-regulation of DHCR24 was associated with advanced clinical stage, histological grading, vascular invasion, lymphatic metastasis, and reduced overall survival. In addition, DHCR24 expression could be induced by insulin though STAT3, which directly binds to the promoter elements of DHCR24, as demonstrated by ChIP-PCR and luciferase assays. Furthermore, genetically silencing DHCR24 inhibited the metastatic ability of endometrial cancer cells and up-regulated PGR expression, which made cells more sensitive to progestin. Taken together, we have demonstrated for the first time the crucial role of the insulin/STAT3/DHCR24/PGR axis in the progression of EC by modulating the metastasis and progesterone response, which could serve as potential therapeutic targets for the treatment of EC with progesterone receptor loss.