Hormonal and reproductive risk factors of papillary thyroid cancer: A population-based case-control study in France

Exploring the Correlation Between Papillary Thyroid Carcinoma (PTC) and the Usage of Oral Contraceptive Pills Among Affected Females

BACKGROUND

The increasing incidence of papillary thyroid carcinoma (PTC), particularly among women, has prompted an investigation into possible associated factors. The effect of oral contraceptive pill (OCP) usage is debatable, with varying and often conflicting results. It is not confirmed whether OCPs have a protective effect against thyroid cancer or an increased risk.

OBJECTIVE

The objective of this study is to investigate the prevalence of OCP usage among females diagnosed with PTC at a tertiary hospital in Saudi Arabia.

METHODS

The study included females aged 18 and above diagnosed with PTC. An OCP user was defined as a female exposed to OCPs for at least one month. Data collection involved chart reviews and phone interviews, and statistical analyses were conducted using Excel and SPSS.

RESULTS

Among 58 female patients diagnosed with PTC, 29.3% (n=17) reported using OCPs, and 70.7% (n=41) were non-users. The ages of OCP users ranged from 26 to 56 years, with a median age of 44 years. The duration of OCP usage varied from 1 to 72 months, with a median duration of seven months. Additionally, for the non-users of OCPs, the age range was from 21 to 85 years, with a mean age of 46.4 years. The median ages for the total sample, OCP users, and non-users were 43.5, 44, and 43 years respectively. The timing of OCP usage among users varied from 1 to 35, with a mean timing of 13.

CONCLUSION

The study found about one-third 29.3% (n=17) of patients diagnosed with PTC reported using OCPs. These results contribute to the ongoing debate within epidemiological studies regarding the association between PTC and various reproductive factors, including OCP use. Further research is needed to clarify this relationship and its implications on public health.

Secular Increasing Trends in Female Thyroid Cancer Incidence in Taiwan

BACKGROUND

Thyroid cancer incidence has increased globally in recent decades, especially in females, although its trends in Taiwan have not been studied extensively. This study aimed to investigate changes in female incidence and possible causes of thyroid cancer in Taiwan.

METHODS

Using the Taiwan Cancer Registry (TCR) Database, age-standardized incidence rates, age-specific incidence rates and birth cohorts were calculated. Correlation between female thyroid cancer incidence and cohort fertility rates were examined.

RESULTS

Thyroid cancer incidence increased in Taiwanese female, with age-adjusted rates per 100,000 people increasing from 7.37 during 1995-1999 to 20.53 during 2015-2019; the annual percentage change (APC) was 5.9% (95% CI, 5.3-6.5). Age-specific incidence rates increased with age, with peak rates occurring at younger ages. The APCs in the 50-54 age group were the highest (6.8%, 95% CI, 6.1-7.5). Incidence rates also increased with later birth cohorts. We observed a significant negative correlation between thyroid cancer incidence and fertility rates in the same birth cohort.

CONCLUSIONS

We hypothesize that overdiagnosis may be a main reason for the rapidly increasing thyroid cancer incidence in Taiwanese females. Notably, we observed a strong negative correlation between fertility and thyroid cancer incidence. However, our study is limited by the absence of individual-level cancer data in the TCR database. These associations with fertility will be an important subject for future thyroid cancer research.

Hormonal Contraceptive Use Is Associated With a Decreased Incidence of Hypothyroidism

OBJECTIVE

Hypothyroidism is one of the most common endocrine disorders affecting 5 to 10 times more women than men. Given this higher incidence in women, it is possible that hormonal differences or medications more commonly used by women may play a role in the risk of developing hypothyroidism. We hypothesized that hormonal contraception affects the risk of developing hypothyroidism.

METHODS

Using the TriNetX database, we developed a case-control study and identified women aged 18 to 45 years in 4 distinct groups: (1) estrogen-progestin contraceptive (EPC) use, (2) progestin-only contraceptive (POC) use, (3) progestin-containing intrauterine device (IUD) use, and (4) controls. For each group, we ascertained data including the diagnosis of hypothyroidism, alcohol use, tobacco use, and body mass index.

RESULTS

We identified 18 578 patients with sufficient data: EPC use, n = 5849; POC use, n = 5052; IUD use, n = 1000; and controls, n = 6677. A total of 118 individuals (1.8%) in the control group and 165 individuals (1.4%) who received hormonal contraception developed hypothyroidism. After using a logistic model to account for cofounding variables, all forms of hormonal contraception (EPC, POC, and IUD) had a protective effect against the diagnosis of hypothyroidism. POC and IUD uses had the greatest protective effect, with odds ratios of 0.14 and 0.12, respectively. EPC had a less pronounced but still significant effect, with an odds ratio of 0.30 (P < .001).

CONCLUSION

This study of >18 000 women and the risk of developing hypothyroidism demonstrates a protective effect of hormonal contraceptive use. Our data, both unadjusted and adjusted using a logistic model to account for cofounding variables, suggest that the use of hormonal contraception, in any form, decreases the risk of developing hypothyroidism.

Rotating Night Shift Work, Sleep, and Thyroid Cancer Risk in the Nurses' Health Study 2

Night shift work has been associated with breast, prostate, and colorectal cancer, but evidence on other types of cancer is limited. We prospectively evaluated the association of rotating night shift work, sleep duration, and sleep difficulty with thyroid cancer risk in the Nurses' Health Study 2 (NHS2). We assessed rotating night shift work duration (years) at baseline and throughout follow-up (1989-2015) and sleep characteristics in 2001. Cox proportional hazard models, adjusted for potential confounders, were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for (a) shift work duration, (b) sleep duration, and (c) difficulty falling or staying asleep. We stratified the analyses of night shift work by sleep duration and sleep difficulty. Over 26 years of follow-up, 588 incident cases were identified among 114,534 women in the NHS2 cohort. We observed no association between night shift work and the risk of thyroid cancer. Difficulty falling or staying asleep was suggestively associated with a higher incidence of thyroid cancer when reported sometimes (HR 1.26, 95% CI 0.95, 1.66) and all or most of the time (HR 1.35, 95% CI 1.00, 1.81). Night shift workers (10+ years) with sleep difficulty all or most of the time (HR 1.47; 0.58-3.73) or with >7 h of sleep duration (HR 2.17; 95% CI, 1.21-3.92) had a higher risk of thyroid cancer. We found modest evidence for an increased risk of thyroid cancer in relation to sleep difficulty, which was more pronounced among night shift workers.

Women consuming oral contraceptives containing cyproterone acetate and ethinylestradiol show a higher risk of thyroid cancer than nonusers

This study explored whether the risk of thyroid cancer in Asian women is associated with consumption of oral contraceptives (Diane-35). We conducted a population-based, retrospective cohort study using the Taiwan National Health Insurance Research Database. From the database, 9865 women aged 18 to 65 years who were prescribed Diane-35 between 2000 and 2012 were included in the Diane-35 group, and 39,460 women who were not prescribed Diane-35 were included in the comparison group and were frequency-matched by age and index year. Both groups were followed until 2013 to calculate the incidence of thyroid cancer. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazard model. The median (standard deviation) follow-up duration was 7.08 (3.63) and 7.04 (3.64) years in the Diane-35 and the comparison group, respectively. The incidence of thyroid cancer was 1.80-fold higher in the Diane-35 group than in the comparison group (2.72 vs 1.51 per 10,000 person-years). The cumulative incidence of thyroid cancer was significantly higher in the Diane-35 group than in the comparison group (log-rank test, P = .03). An elevated hazard ratio of thyroid cancer was observed in the Diane-35 group than in the comparison group (HR: 1.91, 95% CI: 1.10-3.30). In subgroup analysis, patients aged 30 to 39 years showed a higher hazard ratio of developing thyroid cancer after consuming Diane-35 than those in the comparison group (HR: 5.58, 95% CI: 1.84-16.91). The study provides evidence that women aged 30 to 39 years consuming Diane-35 are at increased risk of thyroid cancer. Nevertheless, a larger population with a longer follow-up may be necessary to confirm causality.

A protective factor against lymph node metastasis of papillary thyroid cancer: Female gender

OBJECTIVE

Papillary thyroid carcinoma (PTC) is the most common pathological type of thyroid cancer, with good prognosis, but the rate of lymph node metastasis (LNM) is high, and the difference between men and women is significant. Therefore, the related risk factors for LNM of PTC based on gender were examined in this study in order to draw attention to gender factor in PTC.

METHODS

We retrospectively analyzed the clinicopathological data of 2103 patients with surgically confirmed PTC at the Fourth affiliated Hospital of Hebei Medical University West Side between January 2016 and December 2019.

RESULTS

LNM was detected in 1124 of the 2103 cases of PTC. Logistic regression analysis showed that LNM was associated with age (p < 0.001, OR:0.547), gender (p < 0.001, OR:2.609), tumor diameter (p < 0.001, OR:2.995), bilaterality (p=0.003, OR:1.683), and extrathyroid extension (p < 0.001, OR:1.657). After propensity score matching, female gender (p < 0.001, OR: 0.393) remained an independent factor of LNM in patients with PTC. LNM in men was only associated with diameter (p < 0.001, OR: 3.246). LNM in woman was associated with menopausal history (p = 0.012, OR=0.684), reproductive history (p < 0.001, OR=0.360), abortion history (p = 0.011, OR=0.725), tumor diameter >1 cm (p < 0.001, OR=2.807), bilaterality (p =0.006, OR:1.728), and extrathyroid extension (p < 0.001, OR=1.879).

CONCLUSION

Although the invasion is high in female patients, the rate of LNM is significantly reduced due to the influence of sex hormones and reproductive factors. For female patients of childbearing age who were not pregnant and did not have children, it is suggested to take a positive attitude towards their lymph nodes.

Adapted dietary inflammatory index and differentiated thyroid carcinoma risk in two French population-based case-control studies

PURPOSE

Thyroid cancer is the most common endocrine cancer and its etiology is still not well understood. The aim of the present study was to assess the association between an adapted dietary inflammatory index and differentiated thyroid cancer (DTC) risk in two population-based case-control studies (CATHY and YOUNG-THYR) conducted in France.

METHODS

These studies included a total of 1321 DTC cases and 1502 controls, for which an adapted dietary inflammatory index (ADII) was computed based on food frequency questionnaires in each study separately. The association between ADII and thyroid cancer risk was assessed using logistic regression models controlling for potential confounders.

RESULTS

Higher ADII scores, corresponding to a higher pro-inflammatory potential of the diet, were associated with higher DTC risk (odds ratio (OR) for 1 standard deviation (SD) increase: 1.09, 95% confidence interval (CI): 1.01, 1.18, P: 0.03). Associations were stronger in analyses restricted to women (OR for 1-SD increase: 1.14, 95% CI 1.04, 1.25, P: 0.005), as well as in women with lower education level, current smoking, or high body mass index.

CONCLUSION

Our study suggests that a pro-inflammatory diet is associated with an increased risk of DTC, especially when combined with other inflammatory conditions such as tobacco smoking or overweight. Our findings will help better understand the role of diet-induced inflammation in DTC etiology.

Multiethnic genome-wide association study of differentiated thyroid cancer in the EPITHYR consortium

Incidence of differentiated thyroid carcinoma (DTC) varies considerably between ethnic groups, with particularly high incidence rates in Pacific Islanders. DTC is one of the cancers with the highest familial risk suggesting a major role of genetic risk factors, but only few susceptibility loci were identified so far. In order to assess the contribution of known DTC susceptibility loci and to identify new ones, we conducted a multiethnic genome-wide association study (GWAS) in individuals of European ancestry and of Oceanian ancestry from Pacific Islands. Our study included 1554 cases/1973 controls of European ancestry and 301 cases/348 controls of Oceanian ancestry from seven population-based case-control studies participating to the EPITHYR consortium. All participants were genotyped using the OncoArray-500K Beadchip (Illumina). We confirmed the association with the known DTC susceptibility loci at 2q35, 8p12, 9q22.33 and 14q13.3 in the European ancestry population and suggested two novel signals at 1p31.3 and 16q23.2, which were associated with thyroid-stimulating hormone levels in previous GWAS. We additionally replicated an association with 5p15.33 reported previously in Chinese and European populations. Except at 1p31.3, all associations were in the same direction in the population of Oceanian ancestry. We also observed that the frequencies of risk alleles at 2q35, 5p15.33 and 16q23.2 were significantly higher in Oceanians than in Europeans. However, additional GWAS and epidemiological studies in Oceanian populations are needed to fully understand the highest incidence observed in these populations.

Reproductive and menstrual factors for papillary thyroid cancer risk: A case-control study in Chinese women

BACKGROUND

Thyroid cancer (TC) is threefold more common in women than men. Reproductive and menstrual factors may be related to the onset of papillary thyroid cancer (PTC). This study aims to determine the association of reproductive and menstrual factors with PTC in Chinese females.

METHODS

A total of 335 histologically confirmed cases of PTC were recruited in this case-control study. The controls were matched for age with a deviation of ± 2 years, which conducted from September 2016 to February 2019. Logistic regression models were applied to identify the association of reproductive and menstrual factors with PTC.

RESULTS

After adjustment by some variables, early menarche age (OR ≤ 13 years vs. > 13years = 2.40, 95 % CI 1.12-5.13) and shorter lifetime breastfeeding (OR <6 months vs. ≥ 6 months = 1.99, 95 % CI 1.11-3.55) significantly increased the risk of PTC, whereas younger age at first pregnancy had a protective effect against PTC (OR ≤ 24years vs. > 24 years = 0.66, 95 % CI 0.44-0.98). There was a positive correlation between premenopausal and PTC in the lower age group (OR _{premenopausal vs. Menopause by natural} =2.34, 95 %CI 1.03-5.28).

CONCLUSIONS

Early menarche age, abortion, shorter breastfeeding duration and premenopausal may be related to the occurrence of PTC. Early age at first pregnancy and larger number of full-time pregnancies were possible to decrease the risk of PTC.

Role of DNA Repair Variants and Diagnostic Radiology Exams in Differentiated Thyroid Cancer Risk: A Pooled Analysis of Two Case-Control Studies

BACKGROUND

Given the increased use and diversity of diagnostic procedures, it is important to understand genetic susceptibility to radiation-induced thyroid cancer.

METHODS

On the basis of self-declared diagnostic radiology examination records in addition to existing literature, we estimated the radiation dose delivered to the thyroid gland from diagnostic procedures during childhood and adulthood in two case-control studies conducted in France. A total of 1,071 differentiated thyroid cancer (DTC) cases and 1,188 controls from the combined studies were genotyped using a custom-made Illumina OncoArray DNA chip. We focused our analysis on variants in genes involved in DNA damage response and repair pathways, representing a total of 5,817 SNPs in 571 genes. We estimated the OR per milli-Gray (OR/mGy) of the radiation dose delivered to the thyroid gland using conditional logistic regression. We then used an unconditional logistic regression model to assess the association between DNA repair gene variants and DTC risk. We performed a meta-analysis of the two studies.

RESULTS

The OR/mGy was 1.02 (95% confidence interval, 1.00-1.03). We found significant associations between DTC and rs7164173 in CHD2 (P = 5.79 × 10-5), rs6067822 in NFATc2 (P = 9.26 × 10-5), rs1059394 and rs699517 both in ENOSF1/THYS, rs12702628 in RPA3, and an interaction between rs7068306 in MGMT and thyroid radiation doses (P = 3.40 × 10-4).

CONCLUSIONS

Our results suggest a role for variants in CDH2, NFATc2, ENOSF1/THYS, RPA3, and MGMT in DTC risk.

IMPACT

CDH2, NFATc2, ENOSF1/THYS, and RPA3 have not previously been shown to be associated with DTC risk.

Reproductive Factors and Risk of Thyroid Cancer in Women: An Analysis in the Nurses' Health Study II

BACKGROUND

The incidence of thyroid cancer in women is increasing at an alarming rate, with greatest risk in the reproductive years. Establishing relationships of hormonally related reproductive factors with thyroid cancer has been difficult. We aimed to elucidate potential risk factors for thyroid cancer in a large cohort of women.

METHODS

Among 116,228 women in the Nurses' Health Study II followed from 1989 to 2013, 620 cases of thyroid cancer were identified. We examined reproductive and hormone-related factors, including age at menarche, age at menopause, parity, oral contraceptive use, and postmenopausal hormone therapy use. Pregnancy, reproductive years, and months of breastfeeding were used as surrogate markers for exposure to endogenous reproductive hormones. We used multivariable Cox models to calculate relative risks and 95% confidence intervals for the associations between these factors and risk of thyroid cancer.

RESULTS

Number of reproductive years of 41 years or more was associated with more than double the risk of thyroid cancer compared with 30 years or fewer (relative risk, 2.20; 95% confidence interval, 1.19-4.06). The other variables analyzed (parity number, months of breastfeeding, age at menarche, menopausal status, and postmenopausal hormone therapy) were not associated with the risk of thyroid cancer. Women who entered menopause at age 45 years or older had a higher risk of thyroid cancer compared with women who entered menopause at a younger age. This result did not reach statistical significance; however, there was a linear trend between later age at menopause and increased risk of thyroid cancer (p_trend = .009).

CONCLUSIONS

This study used a unique large, longitudinal dataset to assess thyroid cancer risk factors and potential confounders over an extended time frame. Our key finding suggests increased risk of thyroid cancer may be associated with a variety of indicators of longer reproductive years. The Nurses' Health Study II has provided new insights into the hormonal risks associated with thyroid cancer.

Gene network and biological pathways associated with susceptibility to differentiated thyroid carcinoma

Variants identified in earlier genome-wide association studies (GWAS) on differentiated thyroid carcinoma (DTC) explain about 10% of the overall estimated genetic contribution and could not provide complete insights into biological mechanisms involved in DTC susceptibility. Integrating systems biology information from model organisms, genome-wide expression data from tumor and matched normal tissue and GWAS data could help identifying DTC-associated genes, and pathways or functional networks in which they are involved. We performed data mining of GWAS data of the EPITHYR consortium (1551 cases and 1957 controls) using various pathways and protein-protein interaction (PPI) annotation databases and gene expression data from The Cancer Genome Atlas. We identified eight DTC-associated genes at known loci 2q35 (DIRC3), 8p12 (NRG1), 9q22 (FOXE1, TRMO, HEMGN, ANP32B, NANS) and 14q13 (MBIP). Using the EW_dmGWAS approach we found that gene networks related to glycogenolysis, glycogen metabolism, insulin metabolism and signal transduction pathways associated with muscle contraction were overrepresented with association signals (false discovery rate adjusted p-value < 0.05). Additionally, suggestive association of 21 KEGG and 75 REACTOME pathways with DTC indicate a link between DTC susceptibility and functions related to metabolism of cholesterol, amino sugar and nucleotide sugar metabolism, steroid biosynthesis, and downregulation of ERBB2 signaling pathways. Together, our results provide novel insights into biological mechanisms contributing to DTC risk.

Risk of thyroid cancer following hysterectomy

BACKGROUND

Hysterectomy has been associated with increased thyroid cancer risk but whether this reflects a biological link or increased diagnosis of indolent cancers due to greater medical contact remains unclear.

METHODS

We recruited 730 women diagnosed with thyroid cancer and 785 age-matched population controls. Multivariable logistic regression was used to assess the association overall, and by tumour BRAF mutational status as a marker of potentially higher-risk cancers. We used causal mediation analysis to investigate potential mediation of the association by healthcare service use.

RESULTS

Having had a hysterectomy was associated with an increased risk of thyroid cancer (odds ratio [OR] = 1.45, 95 % confidence interval [CI] 1.07-1.96). When stratified by indication for hysterectomy, the risk appeared stronger for those who had a hysterectomy for menstrual disorders (OR = 1.67, 95 % CI 1.17-2.37) but did not differ by tumour BRAF status. Approximately 20 % of the association between hysterectomy and thyroid cancer may be mediated by more frequent use of healthcare services.

CONCLUSIONS

The observed increased risk of thyroid cancer among those with hysterectomy may be driven, at least partly, by an altered sex steroid hormone milieu. More frequent healthcare service use by women with hysterectomy accounts for only a small proportion of the association.

Fine-mapping of two differentiated thyroid carcinoma susceptibility loci at 2q35 and 8p12 in Europeans, Melanesians and Polynesians

Differentiated thyroid carcinoma (DTC) incidence is characterized by wide ethnic and geographic variations, with high incidence rates observed in Oceanian populations. Genome-wide association studies (GWAS) identified mainly four DTC susceptibility loci at 9q22.33, 14q13.3, 2q35 and 8p12. Here we performed fine-mapping of the 2q35 and 8p12 loci in the population of the EPITHYR consortium that includes Europeans, Melanesians and Polynesians to identify likely causal variants for DTC risk. We conducted a colocalization analysis using eQTLs data to determine the SNPs with the highest probability of causality. At 2q35, we highlighted rs16857609 located in DIRC3. This SNP has a high probability of causality in the three populations, and a significant association in Europeans (OR = 1.4, p = 1.9 x 10-10). It is also associated with expression of DIRC3 and of the nearby gene IGFBP5 in thyroid tumour cells. At 8p12, we identified rs7844425 which was significantly associated with DTC in Europeans (OR = 1.32, p = 7.6 x 10-8) and rs2439304, which was highlighted by the colocalization analysis but only moderately associated with DTC in our dataset (OR = 1.2, p = 0.001). These SNPs are linked to the expression of NRG1 in thyroid tissue. Hence, our study identified novel variants at 2q35 and 8p12 to be prioritized for further functional studies.

Menstrual, reproductive and hormonal factors and thyroid cancer: a hospital-based case-control study in China

BACKGROUND

There have been considerable studies on the effects of reproductive factors on thyroid cancer risk, while findings are inconsistent. In this analysis, we aimed to investigate the associations between menstrual, reproductive and hormonal factors with thyroid cancer occurrence in a population of Chinese women.

METHODS

Using data from a 1:1 matched case-control study performed between 2015 and 2017 in Zhejiang Province of China, a second analysis of 2261 pairs of female subjects was conducted. The possible effects for thyroid cancer were evaluated in logistic regression models by odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Later age at first pregnancy (for > 25 vs. ≦ 20 years, OR: 0.47, 95% CI 0.23-0.96) and longer duration of breast feeding (for 6-12 vs. ≦ 6 months, OR: 0.49, 95% CI 0.24-0.98) were significantly associated with decreased occurrence of thyroid cancer, while no trend was observed. Stratified by age at enrollment, only the association with duration of breast feeding remained significant, but limited to younger women (≦ 50 years).

CONCLUSIONS

Our results suggested that women with later age at first pregnancy or longer breast feeding duration were less likely to have thyroid cancer. These findings supported an influence role of reproductive factors in thyroid cancer risk.

Bayesian meta-analysis models for cross cancer genomic investigation of pleiotropic effects using group structure

An increasing number of genome-wide association studies (GWAS) summary statistics is made available to the scientific community. Exploiting these results from multiple phenotypes would permit identification of novel pleiotropic associations. In addition, incorporating prior biological information in GWAS such as group structure information (gene or pathway) has shown some success in classical GWAS approaches. However, this has not been widely explored in the context of pleiotropy. We propose a Bayesian meta-analysis approach (termed GCPBayes) that uses summary-level GWAS data across multiple phenotypes to detect pleiotropy at both group-level (gene or pathway) and within group (eg, at the SNP level). We consider both continuous and Dirac spike and slab priors for group selection. We also use a Bayesian sparse group selection approach with hierarchical spike and slab priors that enables us to select important variables both at the group level and within group. GCPBayes uses a Bayesian statistical framework based on Markov chain Monte Carlo (MCMC) Gibbs sampling. It can be applied to multiple types of phenotypes for studies with overlapping or nonoverlapping subjects, and takes into account heterogeneity in the effect size and allows for the opposite direction of the genetic effects across traits. Simulations show that the proposed methods outperform benchmark approaches such as ASSET and CPBayes in the ability to retrieve pleiotropic associations at both SNP and gene-levels. To illustrate the GCPBayes method, we investigate the shared genetic effects between thyroid cancer and breast cancer in candidate pathways.

circFAT1(e2) Promotes Papillary Thyroid Cancer Proliferation, Migration, and Invasion via the miRNA-873/ZEB1 Axis

Circular RNAs (circRNAs) play an extremely important regulatory role in the occurrence and development of various malignant tumors including papillary thyroid cancer (PTC). circFAT1(e2) is a new type of circRNA derived from exon 2 of the FAT1 gene, which is distributed in the cytoplasm and nucleus of PTC cells. However, so far, the role of circFAT1(e2) in PTC is still unclear. In this study, circFAT1(e2) was found to be highly expressed in PTC cell lines and tissues. circFAT1(e2) knockdown suppressed PTC cell growth, migration, and invasion. Also, circFAT1(e2) acted as a sponge for potential microRNAs (miRNAs) to modulate cancer progression. A potential miRNA target was discovered to be miR-873 which was targeted by circFAT1(e2) in PTC. The dual-luciferase assay conducted later also confirmed that there was indeed a direct interaction between circFAT1(e2) and miR-873. This study also confirmed that circFAT1(e2) inhibited the miR-873 expression and thus promoted the ZEB1 expression, thus affecting the proliferation, metastasis, and invasion of PTC cells. In conclusion, the results of this study indicated that circFAT1(e2) played a carcinogenic role by targeting the miR-873/ZEB1 axis to promote PTC invasion and metastasis, which might become a potential novel target for therapy of PTC.

The Sex Bias of Cancer

In hormone-dependent organs, sex hormones and dysregulated hormone signaling have well-documented roles in cancers of the breast and female reproductive organs including endometrium and ovary, as well as in prostate and testicular cancers in males. Strikingly, epidemiological data highlight significant differences between the sexes in the incidence of various cancers in nonreproductive organs, where the role of sex hormones has been less well studied. In an era when personalized medicine is gaining recognition, understanding the molecular, cellular, and biological differences between men and women is timely for developing more appropriate therapeutic interventions according to gender. We review evidence that sex hormones also shape many of the dysregulated cellular and molecular pathways that lead to cell proliferation and cancer in nonreproductive organs.

Role of GSTM1 and GSTT1 genotypes in differentiated thyroid cancer and interaction with lifestyle factors: Results from case-control studies in France and New Caledonia

Background

GSTM1 and GSTT1 are involved in detoxification of xenobiotics, products of oxidative stress and in steroid hormones metabolism. We investigated whether GSTM1 and GSTT1 gene deletion was associated with DTC risk and explored interaction with non-genetic risk factors of DTC.

Methods

The study included 661 DTC cases and 736 controls from two case-control studies conducted in France and New Caledonia. Odds ratios (OR) and their confidence interval (CI) for DTC associated with GST genotypes, alcohol drinking, tobacco smoking, body mass index and hormonal factors were calculated using logistic regression models.

Results

Results are presented for Europeans and Melanesians combined, as no heterogeneity between groups was detected. We found that DTC risk increased with obesity and decrease with alcohol drinking. After stratification by gene deletion status, the OR for obesity was 5.75, (95%CI 2.25–14.7) among individuals with GSTT1 and GSTM1-deleted genotype, and 1.26, (95%CI 0.89–1.77) in carriers of both genes (p-interaction = 0.02). The OR for drinking ≥1 glass/week was 0.33 (95%CI 0.15–0.74) in GSTT1-null individuals while it was 1.01 (95%CI 0.67–1.52) in non-null carriers of the gene (p-interaction = 0.01). No interaction between GST genotypes and other non-genetic risk factors was detected.

Conclusion

GSTM1 and GSTT1 genotypes may modulate the DTC risk associated with BMI and alcohol consumption.

Reproductive factors and thyroid cancer risk: Meta-analysis

BACKGROUND

Assessed pooled risk on reproductive factors and oral contraceptives (OC) on thyroid cancer (TC) using published studies (1996-2017).

METHODS

Summary odds ratio (OR) for case-control studies (n = 10) and risk ratio (RR) for cohort studies (n = 9) was done.

RESULTS

OR was 1.43 (95% CI: 1.16-1.77) for age at menarche >14 years, 1.49 (95% CI: 1.19-1.86) for parity >2, 1.38 (95% CI: 1.18-1.61) for miscarriage/abortion, and 2.05 (95% CI: 1.39-3.01) for artificial menopause. A protective effect (ORs: 0.85; 95% CI: 0.72-0.99) on TC was observed for prolonged use of OCs. RR was 1.17 (95% CI: 0.90-1.57) for age at menarche >14 years, 1.10 (95% CI: 0.94-1.27) for parity >2, 1.20 (95% CI: 1.03-1.40) for miscarriage/abortion, and 2.16 (95% CI: 1.41-3.31) for artificial menopause and protective effect (RR: 0.78; 95% CI: 0.65-0.92) for prolonged use of OCs.

CONCLUSIONS

This meta-analysis supports an association due to changes in female hormones during menstrual cycle and pregnancy with the risk of TC and explains female preponderance.

The Relationship Between Human Development Index and Its Components with Thyroid Cancer Incidence and Mortality: Using the Decomposition Approach

BACKGROUND

The link between age specific-rates of thyroid cancer (TC) and human development index (HDI) and also its components can be a new direction for planning by policy makers.

OBJECTIVES

This study aimed at identifying the relationship between TC rates by gender, and HDI and its components in different regions of the world.

METHODS

An ecological study was conducted; the data was obtained from the GLOBOCAN project in 2012. Inequality in TC estimates (age-specific incidence and mortality rates), according to the HDI and its components was calculated. Concentration index (CI) was used to estimate inequality and CI was decomposed to determine contribution of HDI and its components in inequality.

RESULTS

The inequality index (CI) was 0.29 (95% CI: 0.21 - 0.38) and -0.15 (95% CI: -0.23 - 0.06) for incidence and mortality of TC by HDI, respectively. The important contributors in inequality for incidence rates of TC were life expectancy at birth (0.30), mean years of schooling (0.26), and expected years of schooling (0.18). The important contributors in inequality of mortality rates were mean years of schooling (0.19), expected years of schooling (0.17), and urbanization (0.17).

CONCLUSIONS

According to the findings of this study, global inequalities exist in the TC incidence and mortality rates; incidence rates of TC are more concentrated in countries with high HDI, yet inequality index showed that deaths occurred more in disadvantaged countries.

Menstrual and reproductive factors and lung cancer risk: A pooled analysis from the international lung cancer consortium

Many clinical features of lung cancer are different in women and men. Sex steroid hormones exert effects in nonreproductive organs, such as the lungs. The association between menstrual and childbearing factors and the risk of lung cancer among women is still debated. We performed a pooled analysis of eight studies contributing to the International Lung Cancer Consortium (4,386 cases and 4,177 controls). Pooled associations between menstrual or reproductive factors and lung cancer were estimated using multivariable unconditional logistic regression. Subgroup analyses were done for menopause status, smoking habits and histology. We found no strong support for an association of age at menarche and at menopause with lung cancer, but peri/postmenopausal women were at higher risk compared to premenopausal (OR 1.47, 95% CI 1.11-1.93). Premenopausal women showed increased risks associated with parity (OR 1.74, 95% CI 1.03-2.93) and number of children (OR 2.88, 95% CI 1.21-6.93 for more than 3 children; p for trend 0.01) and decreased with breastfeeding (OR 0.54, 95% CI 0.30-0.98). In contrast, peri/postmenopausal subjects had ORs around unity for the same exposures. No major effect modification was exerted by smoking status or cancer histology. Menstrual and reproductive factors may play a role in the genesis of lung cancer, yet the mechanisms are unclear, and smoking remains the most important modifiable risk factor. More investigations in large well-designed studies are needed to confirm these findings and to clarify the underlying mechanisms of gender differences in lung cancer risk.