The impact of obesity and insulin resistance on thyroid cancer: A systematic review

Exploring the Link between BMI and Aggressive Histopathological Subtypes in Differentiated Thyroid Carcinoma-Insights from a Multicentre Retrospective Study

Obesity's role in thyroid cancer development is still debated, as well as its association with aggressive histopathological subtypes (AHSs). To clarify the link between Body Mass Index (BMI) and AHS of differentiated thyroid carcinoma (DTC), we evaluated patients who underwent thyroidectomy for DTC from 2020 to 2022 at four European referral centres for endocrine surgery. Based on BMI, patients were classified as normal-underweight, overweight, or obese. AHSs were defined according to 2022 WHO guidelines. Among 3868 patients included, 34.5% were overweight and 19.6% obese. Histological diagnoses were: 93.6% papillary (PTC), 4.8% follicular (FTC), and 1.6% Hürthle cell (HCC) thyroid carcinoma. Obese and overweight patients with PTC had a higher rate of AHSs (p = 0.03), bilateral, multifocal tumours (p = 0.014, 0.049), and larger nodal metastases (p = 0.017). In a multivariate analysis, BMI was an independent predictor of AHS of PTC, irrespective of gender (p = 0.028). In younger patients (<55 years old) with PTC > 1 cm, BMI predicted a higher ATA risk class (p = 0.036). Overweight and obese patients with FTC had larger tumours (p = 0.036). No difference was found in terms of AHS of FTC and HCC based on BMI category. Overweight and obese patients with PTC appear to be at an increased risk for AHS and aggressive clinico-pathological characteristics.

Insulin Resistance: The Increased Risk of Cancers

Insulin resistance, also known as impaired insulin sensitivity, is the result of a decreased reaction of insulin signaling to blood glucose levels. This state is observed when muscle cells, adipose tissue, and liver cells, improperly respond to a particular concentration of insulin. Insulin resistance and related increased plasma insulin levels (hyperinsulinemia) may cause metabolic impairments, which are pathological states observed in obesity and type 2 diabetes mellitus. Observations of cancer patients confirm that hyperinsulinemia is a major factor influencing obesity, type 2 diabetes, and cancer. Obesity and diabetes have been reported as risks of the initiation, progression, and metastasis of several cancers. However, both of the aforementioned pathologies may independently and additionally increase the cancer risk. The state of metabolic disorders observed in cancer patients is associated with poor outcomes of cancer treatment. For example, patients suffering from metabolic disorders have higher cancer recurrence rates and their overall survival is reduced. In these associations between insulin resistance and cancer risk, an overview of the various pathogenic mechanisms that play a role in the development of cancer is discussed.

Thyroid cancer and insulin resistance

Thyroid cancer has shown a parallel increase with diabetes in the last few years. This narrative review aims to explain the association between these two entities, focusing on insulin resistance as the mediator and exploring the effects of antidiabetic agents on thyroid cancer incidence and progression.We searched Pubmed for English-written articles on insulin resistance, diabetes, antidiabetic treatments, and thyroid cancer reported from January 2019 to April 2023. Exclusion criteria were preclinical and clinical studies involving a population with thyroid dysfunction, benign nodular goiter, or those that only analyzed thyroid cancer's association with obesity.The results of the narrative literature review revealed 96 articles. Additionally, four studies from a manual search were retrieved. After the exclusion criteria were applied, we included 20 studies. Out of 8 studies on insulin-resistant or Metabolic Syndrome patients, all suggest a positive association with thyroid cancer. At the same time, for diabetes, four out of five publications support a link with thyroid cancer. The seven remaining studies on antidiabetics suggest that metformin might benefit thyroid cancer. In contrast, the evidence for an association between Glucagon-like peptide-1 receptor agonists (GLP-1 RA) and increased thyroid cancer findings is limited.In conclusion, the association between thyroid cancer and diabetes may be explained by insulin resistance, as shown in observational studies. However, the causal role is yet to be defined. Although the wide use of different antidiabetic agents has been related to thyroid cancer prevalence and progression, future research with drugs such as metformin or GLP-1 RA is still needed.

Thyroid nodule malignancy is associated with increased non-invasive hepatic fibrosis scores in metabolic subjects

Introduction

Thyroid cancer incidence is increasing, and adiposity-related conditions are gaining space in its pathogenesis. In this study, we aimed to detect any anthropometric, biohumoral, and clinical features that might be associated with thyroid nodule malignancy, potentially representing novel non-invasive markers of thyroid cancer.

Materials and methods

The study was conducted in a group of 142 consecutive outpatients (47 men and 95 women) who underwent fine-needle aspiration biopsy/cytology (FNAB/C) due to suspicion of malignancy from January 2018 to September 2022. We compared lipid and glycemic blood profiles as well as non-invasive liver fibrosis indexes such as aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (AAR), AST to platelet ratio index (APRI), and fibrosis index based on four factors (FIB-4) between patients with benign and malignant newly diagnosed nodules. Then, we performed receiver operating characteristic (ROC) analysis to assess their best cutoff values for discrimination of malignant nodules and chi-squared test to evaluate the association of specific dysmetabolic conditions with malignancy. To understand whether and to what degree dysmetabolic conditions increased the risk of thyroid nodule malignancy, we also calculated the odds ratio (OR) of the main biomarkers.

Results

After FNAB/C, 121 (85%) patients were diagnosed with benign thyroid nodules, while 21 (15%) individuals were diagnosed with thyroid cancer. Comparing patients with benign and malignant nodules, we found that individuals with thyroid cancer exhibited increased body mass index (BMI) (p = 0.048) and fasting plasma glucose (p = 0.046). Intriguingly, considering non-invasive scores for liver fibrosis, subjects with thyroid cancer presented increased AAR (p < 0.001) and APRI (p = 0.007), and these scores were associated with malignancy (p < 0.005) with OR = 7.1 and OR = 5, respectively. Moreover, we showed that only in the cancer group, low levels of vitamin D correlated with stigmata of impaired metabolism.

Discussion

In our study, AAR and APRI scores were associated with thyroid nodule malignancy and could be used to predict it and to speed up the diagnostic process. From a pathogenic point of view, we speculated that metabolic-associated fatty liver disease (MAFLD) along with hyperglycemia and vitamin D deficiency may represent putative drivers of thyroid carcinogenesis.

Polycystic ovary syndrome and thyroid disorder: a comprehensive narrative review of the literature

Background

Published data on the relationship between polycystic ovary syndrome (PCOS) and thyroid dysfunction are sparse and confusing.

Objective

To comprehensively review data available in the literature regarding the relationship between PCOS and the thyroid function, and its abnormalities.

Methods

Nine main areas of interest were identified and analyzed according to the available evidence: 1) Evaluation of thyroid function for PCOS diagnosis; 2) Epidemiology data on thyroid function/disorders in patients with PCOS, and vice versa; 3) Experimental data supporting the relationship between thyroid function/disorders and PCOS; 4) Effects of thyroid function/disorders on PCOS features, and vice versa; 5) Effect of thyroid alterations on the cardiometabolic risk in women with PCOS; 6) Effect of thyroid abnormalities on reproductive outcomes in women with PCOS; 7) Relationship between thyroid function/abnormalities in patients with PCOS who are undergoing fertility treatment; 8) Effect of treatments for thyroid diseases on PCOS; and 9) Effect of treatments for PCOS on thyroid function. An extensive literature search for specific keywords was performed for articles published from 1970 to March 2023 using PubMed and Web of Science. Data were reported in a narrative fashion.

Results

PCOS is a diagnosis of exclusion for which diagnosis is possible only after excluding disorders that mimic the PCOS phenotype, including thyroid dysfunctions. However, the tests and the cutoff values used for this are not specified. Many experimental and clinical data suggest a relationship between perturbations of the thyroid function and PCOS. Direct and unequivocal evidence on the effects of thyroid function/disorders on PCOS features are lacking. High thyroid-stimulating hormone levels and subclinical hypothyroidism may be associated with significant worsening of several intermediate endpoints of cardiometabolic risk in women with PCOS. Thyroid abnormalities may worsen reproductive outcomes, especially in patients undergoing fertility treatment. To date, there are no data demonstrating the efficacy of thyroid medications on fertility and cardiometabolic risk in women with PCOS. Lifestyle modification changes, metformin, and vitamin D seem to improve thyroid function in the general population.

Conclusion

PCOS and thyroid disorders are closely related, and their coexistence may identify patients with a higher reproductive and metabolic risk. Regular screening for thyroid function and thyroid-specific autoantibodies in women with PCOS, particularly before and during pregnancy, is highly recommended.

Association between dietary habits and incident thyroid cancer: A prospective cohort study

Background

In addition to the thyroid cancer (TC) risk from lifestyle and environmental factors such as radiation exposure, some studies have indicated that diet may affect TC development; however, previous findings are inconsistent. The objective of our study was to investigate the association between dietary habits and TC risk in a Korean population.

Materials and methods

A total of 13,973 participants were selected after excluding ineligible subjects from the Cancer Screenee Cohort at National Cancer Center in Korea from October 2007 to December 2021. Participants were followed until May 2022 to identify incident TC cases. Information on dietary habits and general characteristics was collected using a self-report questionnaire administered at enrollment without keeping track of changes in eating habits during the follow-up period. A Cox proportional hazards model was used to determine the hazard ratio (HR) and 95% confidence interval (CI) of TC risk for each dietary factor.

Results

A total of 138 incident TC cases were identified during the median follow-up period of 7.6 years. Of the 12 dietary habits evaluated, only two habits showed significant associations with TC. A significantly decreased TC risk was found among participants who consumed milk and/or dairy products 5 or more days a week [adjusted HR (aHR), 0.58; 95% CI, 0.39-0.85]. Notably, a stronger protective effect of dairy consumption was observed in participants aged ≥ 50 years (aHR, 0.44; 95% CI, 0.26-0.75), in women (aHR, 0.53; 95% CI, 0.35-0.81), and in non-smokers (aHR, 0.60; 95% CI, 0.39-0.92). There was a reduced risk of TC in participants with meal durations longer than 10 min (aHR, 0.58; 95% CI, 0.41-0.83). However, this association was limited to individuals aged ≥ 50 years (aHR, 0.49; 95% CI, 0.31-0.79), women (aHR, 0.61; 95% CI, 0.41-0.90), and non-smokers (aHR, 0.62; 95% CI, 0.41-0.92).

Conclusion

Our findings suggest that consuming milk and/or dairy products 5 or more days a week and having a meal duration longer than 10 min could be protective factors against TC, especially in individuals aged ≥ 50 years, women and non-smokers. Further prospective studies are needed to investigate the association of dietary intake with specific types of TC.

Thyroid gland cancer and insulin resistance: a modern view of the problem

Background. The impact of insulin resistance on the probability of increase in thyroid cancer risk has been drawing a lot of attention of researchers lately. This problem is far from being completely solved. Studying this interrelationship may influence the effectiveness of the treatment of the mentioned widespread pathology. Purpose – to review present literature sources on research of interrelationship between insulin resistance and thyroid cancer, and also possible mechanisms of this relationship. Materials and methods. Literature search was performed manually by the keywords (thyroid cancer, insulin resistance, IGF-1, IGF-2, abdominal obesity, increase in body mass index, metformin), and also literature sources from evidential data bases PubMed, Web of Science were reviewed. Metaanalyses, systematic reviews and cohort studies were also taken into account. 148 literature sources were studied in total. The sources, which had been published within the last 10 years, were preferably selected. Results. Insulin resistance is viewed as an important independent factor of development of numerous malignancies. The carcinogenic activity of insulin resistance is caused by the resistance itself, as well as by the metabolic disorders related to it. It has been established that excessive weight and obesity are to a great extent attributed to more aggressive clinical pathological signs of thyroid cancer. Recent research showed a larger volume of thyroid and higher risk of knot forming in patients with insulin resistance. Thus, thyroid cancer is one of the main factors of thyroid transformation. Therapeutic methods of eliminating metabolic syndrome and associated hormonal diseases for prevention and therapy of oncologic diseases are drawing ever-greater scientific interest. The anti-tumor features of metformin and its capability of retarding carcinogenesis are shown in the studies. Conclusions. The given literature analysis has proved that the problem of treating malignant thyroid tumors and their metastasis is caused not only by morphological, cellular and molecular-biological features of the tumor itself, but also by insufficient knowledge about the interrelationship between insulin resistance, abdominal obesity, increase in body mass index, high-calorie diet and reduction of consumption of polyunsaturated fats, harmful impact of environment with molecular changes, specific for thyroid cancer. It is confirmed by a significant increase in thyroid cancer rate, especially papillary histotype, alongside with an increase in obesity rate. The studying of possibilities of decreasing incidence and mortality rates of oncologic pathology when using medications, which stabilize insulin and contribute to a decrease in degree of hyperinsulinemia, one of which is metformin, generates profound interest

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Obesity and Thyroid Cancer Risk: An Update

Thyroid cancer (TC) is the most common endocrine malignancy worldwide and its incidence has increased dramatically in recent years. In parallel, the prevalence of overweight and obesity has also increased, suggesting a possible link between these two diseases. Indeed, low-grade chronic inflammation, altered cytokine levels, insulin resistance, oxidative stress, and hormonal changes that occur in obese patients are all factors that contribute to the occurrence and growth of TC. In this review, the most recent evidence supporting the potential role of the mechanisms linking obesity to TC will be discussed.

The association of obesity with thyroid carcinoma risk

Background

The prevalence of obesity and an increased incidence of thyroid carcinoma (TC) threaten public health in parallel on a global scale. Sufficient evidence supports excess body fatness in thyroid carcinogenesis, and the role and anthropometric markers of obesity have been causally associated with the rising risk of TC.

Methods

A literature search was conducted in PubMed. Studies focused on the effect of obesity in TC.

Results

This review mainly discusses the global incidence and prevalence of obesity‐related TC. We also review the role of obesity in TC and potential clinical strategies for obesity‐related TC.

Conclusions

Excess body fatness in early life and TC survival initiate adverse effects later in life.

The incidence of thyroid cancer has been increasing in the last decades all over the world. Such a steady growth cannot be entirely attributable to more sensitive diagnostic procedures. Obesity has increased with sufficient rapidity in the same time frame and may as possible promoters and modifiable risk factors for thyroid cancer in recent years. The aim of this review was to focus on the relationship between obesity and the risk of thyroid cancer. Obesity seems to play a relevant role in thyroid cancer carcinogenesis as well as in its severity and aggressiveness. The possible underlying mechanism is involved chronic inflammation mediated by cytokines, leptin, and adiponectins.

Influence of Obesity Parameters on Different Regional Patterns of Lymph Node Metastasis in Papillary Thyroid Cancer

OBJECTIVE

Obesity increases risk of thyroid cancer. However, the association between obesity and the progression of papillary thyroid cancer (PTC) remains controversial. This retrospective study aimed to explore the relationship between obesity and regional patterns of lymph node metastasis (LNM) in PTC.

METHODS

We retrospectively reviewed data from 1015 patients with PTC. We calculated obese parameters, such as body mass index (BMI), body fat percentage (BFP), and body surface area (BSA). Logistic regression models were used to assess associations between obese parameters and the rate of lymph node metastasis (LNM), number of LNM, pattern of LNM, and lymph node ratio (LNR).

RESULTS

Higher BMI was not associated with different regional patterns of LNM in PTC. In men with PTC, high BFP was an independent predictor of total LNM, central lymph node metastasis (CLNM), total lateral lymph node metastasis (LLNM), multiple lateral lymph node metastasis, and simultaneous metastasis in lateral compartment. In addition, male patients with high BFP had higher central LNR and higher number of CLNM. For women, high BSA was an independent predictor of LLNM and level IV metastasis. Female patients with high BSA had higher number of CLNM.

CONCLUSION

BFP and BSA, possibly influenced by gender, were positively associated with the number and risk of LNM in different regions of PTC patients. However, BMI was not the predictor for aggressiveness of PTC in terms of LNM. Clinical decision-making for regional LNM in PTC patients should consider the factor of obesity.

Obesity, metabolic syndrome, and cancer: pathophysiological and therapeutic associations

Overweight, obesity, and metabolic syndrome (MetS) have become epidemic conditions affecting 39%, 13%, and 20% of the population respectively. The aim of this article is to review the literature on the association of obesity and MetS with the risk of cancer. We also explore the effect of lifestyle modifications, such as diet, physical activity, and antidiabetic medications, on cancer incidence. Increased body mass index (BMI) has been associated with a multitude of site-specific cancers, reaching relative risk (RR) 1.54 [95% confidence interval (CI) 1.47-1.61] per 5 unit increase for endometrial cancer, as well as with overall cancer risk (RR 1.03, 95% CI 1.02-1.05). Central adiposity measured by waist circumference or waist-to-hip ratio has been suggested as a stronger predictor than BMI for several cancers, such as colorectal cancer. Metabolic Syndrome has been consistently and positively associated with the risk of very common cancers like colorectal (RR 1.34, 95% CI 1.24-1.44), endometrial (RR 1.62, 95% CI 1.26-2.07) and postmenopausal breast cancer (RR 2.01, 95% CI 1.55-2.60). Hyperglycemia and subsequently T2DM have been also shown to increase the risk of cancer. Nevertheless, these risk factors are modifiable and therefore implementing lifestyle modifications could prevent an important number of cancer cases. Adherence to cancer prevention guidelines, including maintaining a healthy weight, having regular physical exercise (RR 0.58-0.90 for different cite specific cancers) and following a healthy dietary pattern (RR 0.74-0.94 for different cite specific cancers) have a protective effect on the risk of cancer. The strength of this review is the presentation of the best evidence, as the data derive mainly from meta-analyses. Public health policies should focus on the modification of risk factors and future research is needed to reveal the pathophysiological links between these risk factors and cancer to develop more efficient prevention and treatment strategies.

Current mechanisms in obesity and tumor progression

PURPOSE OF REVIEW

Hyperadiposity, as present in obesity, is a substantial threat to cancer risk and prognosis. Studies that have investigated the link between obesity and tumor progression have proposed several mechanistic frameworks, yet, these mechanisms are not fully defined. Further, a comprehensive understanding of how these various mechanisms may interact to create a dynamic disease state is lacking in the current literature.

RECENT FINDINGS

Recent work has begun to explore not only discrete mechanisms by which obesity may promote tumor growth (for instance, metabolic and growth factor functions of insulin; inflammatory cytokines; adipokines; and others), but also how these putative tumor-promoting factors may interact.

SUMMARY

This review will highlight the present understanding of obesity, as it relates to tumor development and progression. First, we will introduce the impact of obesity in cancer within the dynamic tumor microenvironment, which will serve as a theme to frame this review. The core of this review will discuss recently proposed mechanisms that implicate obesity in tumor progression, including chronic inflammation and the role of pro-inflammatory cytokines, adipokines, hormones, and genetic approaches. Furthermore, we intend to offer current insight in targeting adipose tissue during the development of cancer prevention and treatment strategies.

Thyroid surgery in obese patients: A review of the literature

The incidence of obesity in the general population has tripled in the past four decades. The number of bariatric surgeries performed annually has quadrupled in the past ten years due to this obesity epidemic. Concomitantly, the number of patients who are obese or who have undergone bariatric surgery and have become candidates for thyroid surgery has also increased considerably. Among patients undergoing thyroidectomy in the French population, the proportion of obese patients currently represents 10 to 20%. In addition, the frequency of benign and malignant thyroid pathologies seems to be increased by obesity, with a Hazard Ratio of around 1.8 for thyroid cancers in obese women. While obesity does not seem to influence the specific post-operative morbidity of thyroidectomy, a history of malabsorptive bariatric surgery should encourage the greatest caution in patients who need to undergo thyroid surgery since it is associated with a significant risk of severe hypocalcemia (>60% in some studies) requiring intravenous calcium supplementation in about 20% of cases. In the latter situation, peri-operative vitamin D-calcium supplementation is essential. In addition, the replacement dose of Levothyroxine (T4) intended for replacement must also be adapted in obese patients, calculated not from the actual weight but from the ideal weight. The objective of this review is to discuss the influence of obesity on the evolution of nodular and neoplastic thyroid pathologies, on the morbidity of thyroid surgery as well as on post-operative drug treatments. The impact of bariatric surgery on these different aspects is also discussed.

Relations of prediabetes and type 2 diabetes to the thyroid cancer

OBJECTIVE

Patients with type 2 diabetes (T2DM) generally experience a higher incidence of cancer. However, the association between T2DM and thyroid cancer is inconclusive.

METHODS

Case-control prospective study, 722 patients were screened for T2DM and prediabetes (PDM) and underwent thyroid ultrasound and biochemical tests. The patients were assigned to groups of PDM (n=55), T2DM (n=79) or a non-diabetes group (NDM) (n=588). Fine needle aspiration biopsy was carried out in 263 patients. Histological examinations were done for 109 patients after surgery, with findings of 52 benign (BS) and 57 malignant tumors (MS).

RESULTS

33 % of patients with T2DM and especially PDM were newly diagnosed by our screening: 6.5 % with T2DM and 72 % with PDM, respectively. The percentage of thyroid cancers did not significantly differ between the groups (χ2 test=0.461; p=0.794). Relevant positive thyroid predictors for T2DM (t-statistic=25.87; p<0.01) and PDM (21.69; p<0.01) contrary to NDM (-26.9; p<0.01) were thyroid volume (4.79; p<0.01), thyroid nodule volume (3.25; p<0.01) and multinodular thyroid gland (4.83; p<0.01), while negative relevant predictors included the occurrence of autoimmune thyroid disease (AITD) (-2.01; p<0.05).

CONCLUSION

In general, we did not observe an increased risk for thyroid cancer in the diabetic and prediabetic groups in comparison to controls, in spite of well-established increased risk for other malignancies. Structural and benign changes such as larger and multinodular thyroid glands, in comparison to autoimmune thyroid disease, are present more often in diabetics.

Effect of sidt2 Gene on Cell Insulin Resistance and Its Molecular Mechanism

BACKGROUND

Sidt2 (SID1 transmembrane family, member 2) is a multiple transmembrane lysosomal membrane protein newly discovered in our previous study. In the previous study, we used gene targeting technique to make a mouse model of sidt2 gene knockout (sidt2^-/-). It was found that sidt2^-/- mice showed elevated fasting blood glucose and impaired glucose tolerance, showing a disorder of glucose metabolism, suggesting that sidt2 may be closely related to insulin resistance. We used 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells as subjects to observe the effects of sidt2 on insulin-stimulated glucose uptake and the abovementioned insulin signal transduction pathways, and then to explore the effect of sidt2 on peripheral tissue insulin resistance and its possible molecular mechanism.

METHODS

(1) Lentiviruses with sidt2 gene knockout and puromycin resistance were constructed by Crispr/cas9 vector and transfected into 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells to construct sidt2 knockout cell line model. (2) Glucose uptake of 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells stimulated by insulin was detected by glucose detection kit, and the results were analyzed. (3) Sidt2 knockout group and control group of 3T3-L1 adipocytes, C2-C12 myoblast, and HEPA1-6 hepatoma cells were cultured according to the routine method. The total proteins of the above cells were extracted, and the expression of PAKT (thr308), PI3-K, and PIRS-1 (ser307) in the IRS-1 signaling pathway of the three groups was detected by western blot technique.

RESULTS

(1) The sidt2 elimination models of 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells were successfully constructed. (2) It was found that the glucose uptake of cells in the sidt2 knockout group was lower than that in normal group under insulin stimulation through the detection of glucose concentration in the cell culture medium. (3) It was found that the expression of PAKT (thr308) and PI3-K protein decreased and the expression of PIRS-1 (ser307) protein increased in sidt2^-/- group compared to the control group.

CONCLUSIONS

sidt2 knockout can reduce glucose uptake in peripheral tissue under insulin stimulation, which may lead to peripheral tissue insulin resistance by affecting the IRS-1 signal pathway.

Estimating the magnitude of cancer overdiagnosis in Australia

Objectives

To estimate the proportion of cancer diagnoses in Australia that might reasonably be attributed to overdiagnosis by comparing current and past lifetime risks of cancer.

Design, setting, and participants

Routinely collected Australian Institute of Health and Welfare national data were analysed to estimate recent (2012) and historical (1982) lifetime risks (adjusted for competing risk of death and changes in risk factors) of diagnoses with five cancers: prostate, breast, renal, thyroid cancers, and melanoma.

Main outcome measure

Difference in lifetime risks of cancer diagnosis between 1982 and 2012, interpreted as probable overdiagnosis.

Results

For women, absolute lifetime risk increased by 3.4 percentage points for breast cancer (invasive cancers, 1.7 percentage points), 0.6 percentage point for renal cancer, 1.0 percentage point for thyroid cancer, and 5.1 percentage points for melanoma (invasive melanoma, 0.7 percentage point). An estimated 22% of breast cancers (invasive cancers, 13%), 58% of renal cancers, 73% of thyroid cancers, and 54% of melanomas (invasive melanoma, 15%) were overdiagnosed, or 18% of all cancer diagnoses (8% of invasive cancer diagnoses). For men, absolute lifetime risk increased by 8.2 percentage points for prostate cancer, 0.8 percentage point for renal cancer, 0.4 percentage point for thyroid cancer, and 8.0 percentage points for melanoma (invasive melanoma, 1.5 percentage points). An estimated 42% of prostate cancers, 42% of renal cancers, 73% of thyroid cancers, and 58% of melanomas (invasive melanomas, 22%) were overdiagnosed, or 24% of all cancer diagnoses (16% of invasive cancer diagnoses). Alternative assumptions slightly modified the estimates for overdiagnosis of breast cancer and melanoma.

Conclusions

About 11 000 cancers in women and 18 000 in men may be overdiagnosed each year. Rates of overdiagnosis need to be reduced and health services should monitor emerging areas of overdiagnosis.

BRAF and TERT mutations in papillary thyroid cancer patients of Latino ancestry

Papillary thyroid cancer (PTC) is the second most commonly diagnosed malignancy in U.S. Latinas and in Colombian women. Studies in non-Latinos indicate that BRAF and TERT mutations are PTC prognostic markers. This study aimed to determine the prevalence and clinical associations of BRAF and TERT mutations in PTC Latino patients from Colombia. We analyzed mutations of BRAF (V600E) and TERT promoter (C228T, C250T) in tumor DNA from 141 patients (75 with classical variant PTC, CVPTC; 66 with follicular variant PTC, FVPTC) recruited through a multi-center study. Associations between mutations and clinical variables were evaluated with Fisher exact tests. Survival was evaluated with Kaplan-Meier plots. Double-mutant tumors (BRAF+/TERT+, n = 14 patients) were more common in CVPTC (P = 0.02). Relative to patients without mutations (n = 48), double mutations were more common in patients with large tumors (P = 0.03), lymph node metastasis (P = 0.01), extra-thyroid extension (P = 0.03), and advanced stage (P = 6.0 × 10-5). In older patients, TERT mutations were more frequent (mean age 51 years vs 45 years for wild type TERT, P = 0.04) and survival was lower (HR = 1.20; P = 0.017); however, given the small sample size, the decrease in survival was not statically significant between genotypes. Comparisons with published data in US whites revealed that Colombian patients had a higher prevalence of severe pathological features and of double-mutant tumors (10 vs 6%, P = 0.001). Mutations in both oncogenes show prognostic associations in Latinos from Colombia. Our study is important to advance Latino PTC precision medicine and replicates previous prognostic associations between BRAF and TERT in this population.