[Plasma insulin, IGF-I and breast cancer]

Association between metabolic syndrome, insulin resistance, and IGF-1 in breast cancer survivors of DIANA-5 study

PURPOSE

Circulating insulin-like growth factor-1 (IGF-1) is positively associated with the risk of BC recurrence, and is more frequently dysregulated in older people, especially in those with metabolic syndrome (MetS) and obesity. This study aimed to analyze the association between IGF-1 levels and indices of MetS and insulin resistance in BC survivors.

METHODS

Baseline data of 563 BC survivors enrolled in the DIet and ANdrogen-5 (DIANA-5; NCT05019989) study were analyzed.

RESULTS

Lower circulating IGF-1 levels in subjects with MetS than in those without MetS were found. After stratification of the patients according to the diagnosis of MetS, we highlighted that the insulin was the main predictor of elevated IGF-1 levels only in subjects without MetS. Moreover, we found an interaction between high-density lipoprotein cholesterol (HDL-C), glycemia, and IGF-1 levels, showing a positive correlation between HDL-C and IGF-1, especially in subjects with higher values of glycemia and without a diagnosis of MetS.

CONCLUSIONS

While IGF-1 levels appear to be much more impaired in subjects diagnosed with MetS, in non-MetS subjects, IGF-1 levels may respond better to metabolic parameters and lifestyle changes. Further studies are needed to analyze the role of physical activity and/or dietary intervention in modulating IGF-1 concentrations in BC survivors.

IMPLICATIONS FOR CANCER SURVIVORS

These results could have important clinical implications for planning customized strategies aimed at modulating IGF-1 levels in BC survivors. In fact, while the IGF-1 system seems to be much more compromised in subjects with a diagnosis of MetS, in noMetS subjects, IGF-1 levels could better respond to lifestyle changes.

Sugar-sweetened beverage consumption and breast composition in a longitudinal study of Chilean girls

Background

Frequent sugar-sweetened beverage (SSB) intake has been associated with indirect markers of breast cancer risk, such as weight gain in adolescents and early menarche. How SSB intake relates to breast composition in adolescent girls has not been explored.

Methods

We evaluated the association between prospective intake of SSB and breast density in a cohort of 374 adolescent girls participating in the Growth and Obesity Cohort Study in Santiago, Chile. Multivariable linear regression models were used to analyze the association between average daily SSB intake quartiles and breast composition (absolute fibroglandular volume [aFGV], percent fibroglandular volume [%FGV], total breast volume [tBV]). Models were adjusted for potential confounding by BMI Z-score, age, daily energy intake (g/day), maternal education, hours of daily television watching after school, dairy intake (g/day), meat intake (g/day), waist circumference, and menarche. To examine the sensitivity of the association to the number of dietary recalls for each girl, analyses were further stratified by girls with one dietary recall and girls with > one dietary recall.

Results

A total of 881 dietary recalls were available for 374 girls prior to the breast density assessment. More than 60% of the cohort had > one dietary recall available. In multivariable analyses, we found no association between SSB intake quartile and aFGV (Q2 vs Q1 β: − 5.4, 95% CI − 15.1, 4.4; Q3 vs Q1 β: 1.3, 95% CI − 8.6, 11.3; Q4 vs Q1 β: 3.0, 95% CI − 7.1, 13). No associations were noted for %FGV and tBV. Among girls with at least one dietary recall, we found no significant associations between SSB intake quartiles and %FGV, aFGV, or tBV.

Conclusion

Overall, we observed no evidence that SSB intake was associated with breast density in adolescent Chilean girls.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01495-8.

Dietary Insulin Index and Insulin Load in Relation to Breast Cancer: Findings from a Case-Control Study

BACKGROUND

No data are available on the association between dietary insulin index (DII) and dietary insulin load (DIL) and the risk of breast cancer (BC).

PATIENTS AND METHODS

This hospital-based case-control study enrolled 150 newly diagnosed cases of BC and 150 age-matched controls. All cases were patients with pathologically confirmed BC, with no history of any type of other pathologically confirmed cancers. Controls were selected from visitors, relatives, and friends of non-cancer patients in other wards who had no family relationships with the cases. We assessed the dietary intakes of study participants using a validated 147-item semiquantitative food frequency questionnaire. DII and DIL were obtained from previously published data.

RESULTS

A significant positive association was found between DII and BC (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.02-3.25), such that after considering energy intake and age, participants in the highest tertile of DII had 1.86 times greater risk of BC than those in the lowest tertile (OR, 1.86; 95% CI, 1.03-3.35). However, this association became non-significant after controlling for further potential risk factors (OR, 3.26; 95% CI, 0.9-11.7). Furthermore, we observed a significant positive association between DIL and BC (OR, 1.9; 95% CI, 1.06-3.40). The association remained significant even after controlling for age and energy intake. Further controlling for other potential confounders resulted in the disappearance of the association (OR, 3.06; 95% CI, 0.87-10.6).

CONCLUSION

Adherence to a diet with high DII and DIL was not associated with odds of BC after controlling for potential confounders.

Adherence to the low carbohydrate diet and the risk of breast Cancer in Iran

Background

Previous studies on the link between macronutrients and breast cancer have mostly focused on individual macronutrients rather than their combination. This study investigates the association between adherence to a low carbohydrate diet and odds of breast cancer among women.

Methods

This hospital-based case-control study was carried out on 412 women with pathologically confirmed breast cancer within the past year and 456 apparently healthy controls that were matched in terms of age and residential place. Dietary data was collected using a 168-item validated FFQ. Participants were classified in terms of quintiles of percentages of energy intake from carbohydrates, proteins, and fats. Then, individuals in the highest quintile of fat and protein intake were given a score of 5 and those in the lowest quintile of these macronutrients were given a score of 1. Participants in the other quintiles of these macronutrients were given the corresponding score. In terms of carbohydrate intake, those in the highest quintile received a score of 1 and those in the lowest quintile received 5. The scores were then summed up to calculate the total low carbohydrate diet (LCD) score, which varied from 3 to 15. A higher score meant greater adherence to a low carbohydrate diet.

Results

The mean age of study participants was 45.2 y and mean BMI was 28.4 kg/m². Mean LCD score of participants was 8.9 ± 2.5 (8.9 ± 2.6 in cases and 9.0 ± 2.5 in controls). Although no significant association was observed between adherence to the LCD score and odds of breast cancer in the study population, a trend toward significant positive association was seen between consumption of LCD and odds of breast cancer in postmenopausal women; after controlling for several potential confounders, individuals in the third quartile of LCD score were 1.94 times more likely to have breast cancer than those in the lowest quartile (95% CI: 1.00, 3.76). This association strengthened after controlling for dietary variables (2.50; 1.18–5.32). Even after further adjustment for BMI, this association remained significant (2.64, 1.23–5.67). No significant relationship was observed in premenopausal women, either before or after controlling for confounders.

Conclusion

Adherence to LCD may be associated with increased odds of breast cancer in postmenopausal women. Prospective cohort studies are needed to confirm these findings.

The association between the inflammatory potential of diet and risk of developing, and survival following, a diagnosis of ovarian cancer

PURPOSE

Inflammation has been implicated in ovarian carcinogenesis. This study evaluated two dietary indices: the Dietary Inflammatory Index (DII®) and the Empirical Dietary Inflammatory Pattern (EDIP), in relation to risk of developing, and survival following, a diagnosis of ovarian cancer.

METHODS

Data came from the Australian Ovarian Cancer Study (1375 cases, 1415 population controls). DII and EDIP scores were computed from dietary information obtained using a semiquantitative food-frequency questionnaire. Logistic regression was used to assess the association between DII and EDIP scores and risk of ovarian cancer and proportional hazards models were used for survival analysis.

RESULTS

A high DII score, reflecting a more pro-inflammatory diet, was associated with a modest increased risk of ovarian cancer [odds ratio (OR) DII score_{Q4 vs.Q1} = 1.31, 95% CI 1.06-1.63, p_trend = 0.014]. Likewise a high EDIP score was associated with an increase in risk of ovarian cancer [OR EDIP score_{Q4 vs.Q1} = 1.39, 95% confidence interval (CI) 1.12-1.73, p_trend = 0.002]. We found no association between DII or EDIP score and overall or ovarian cancer-specific survival.

CONCLUSION

In conclusion, our results suggest that a pro-inflammatory diet modestly increases the risk of developing ovarian cancer.

Small leucine-rich proteoglycans (SLRPs) in the endometrium of polycystic ovary syndrome women: a pilot study

Background

Small leucine-rich proteoglycans (SLRPs) play an important role in tissue homeostasis and cell proliferation since these proteoglycans sequester multiple growth factors. However, the content of SLRPs in the endometrium of polycystic ovary syndrome (PCOS) women is unknown. Our purpose was to test the hypothesis that excessive endometrial proliferation in PCOS may be partly related to abnormalities in SLRPs.

Methods

In a cross section study a total of 20 endometrial samples were collected from 10 patients with PCOS and 10 ovulatory women during their proliferative (pre-ovulatory) phase. The study subjects were matched for age, body mass index and race. The age range was 20 to 35 years. All volunteers were evaluated in reproductive endocrinology clinic, Gynecology Division, Clinics Hospital, University of São Paulo Medical School Profile and concentration of small leucine-rich proteoglycans (decorin, lumican, fibromodulin and biglycan) were determined by immunohistochemical testing and Western blotting.

Results

Decorin and lumican demonstrated higher immunoreactivity and relative expression in the endometrium of women with PCOS compared to that of women with regular menstrual cycles.

Conclusion

Our data suggests that the endometrium of PCOS women demonstrate a greater content of SLRP than controls; decorin and lumican, in particular, were found in higher concentrations in the endometrium of PCOS women during the proliferative phase. These differences may, in part, explain the excess of endometrial proliferation frequently observed in PCOS. Further studies are warranted.

Dairy intake in relation to breast and pubertal development in Chilean girls

Background: Frequent dairy consumption in childhood has been related to higher growth-hormone concentrations that may affect mammary gland and pubertal development.Objective: We evaluated the relation of dairy intake to breast composition at Tanner stage 4 and age at menarche.Design: A total of 515 Chilean girls are included in the Growth and Obesity Cohort Study. The subjects have been followed longitudinally since they were 3-4 y old (from 2006 to the present). Starting in 2013, diet was assessed every 6 mo via a 24-h recall. The breast fibroglandular volume (FGV) was measured with the use of dual-energy X-ray absorptiometry at Tanner stage 4. The date of menarche was reported every 6 mo. Our analysis included 290 girls with data on prospective diet and breast composition and 324 girls with data on prospective diet and age at menarche.Results: The mean ± SD breast FGV and percentage of fibroglandular volume (%FGV) (i.e., FGV divided by total breast volume times 100) at Tanner stage 4 was 81.7 ± 32.2 cm³ and 42.0% ± 16.7%, respectively. Only sweetened, artificially flavored milk-based drinks were associated with the %FGV with girls who consumed >125 g/d having a %FGV that was 4.5% (95% CI: 0.9%, 8.1%) higher than that of girls who consumed none (P-trend = 0.007). Yogurt intake was associated with a lower FGV. Specifically, girls who consumed >125 g yogurt/d had -10.2 cm³ (95% CI: -20.2, -0.3 cm³) less FGV than did girls who consumed no yogurt (P-trend = 0.03). The majority (90.7%) of girls in our cohort attained menarche before the data analyses with a mean ± SD age at menarche of 11.9 ± 0.7 y. In multivariable models, low-fat dairy, low-fat milk, and yogurt intakes were associated with a later age at menarche. In particular, girls who consumed >125 g yogurt/d had menarche, on average, 4.6 mo (95% CI: 1.9, 7.4 mo) later than girls who consumed no yogurt (P-trend = 0.01).Conclusion: More-frequent consumption of sweetened, artificially-flavored milk-based drinks is associated with a higher %FGV, whereas higher yogurt intake is associated with a lower FGV and delayed age at menarche in Chilean girls.

Metabolic syndrome and outcomes following early-stage breast cancer

The prevalence of risk factors contributing to metabolic syndrome (MetS) is increasing, and numerous components of MetS are associated with increased primary breast cancer (BC) risk. However, less is known about the relationship of MetS to BC outcomes. The aim of this study was to evaluate whether MetS, characterized by increased weight, hypertension, low HDL-cholesterol, high triglycerides, and diabetes or impaired glucose tolerance, is associated with risk of second breast cancer events (SBCE) and BC-specific mortality. Retrospective cohort study of women diagnosed with incident early-stage (I-II) BC between 1990 and 2008, enrolled in an integrated health plan. Outcomes of interest were SBCE, defined as recurrence or second primary BC, and BC-specific mortality. We used multivariable Cox proportional hazards models to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for time-varying exposure to MetS components while accounting for potential confounders and competing risks. Among 4,216 women in the cohort, 26% had ≥3 MetS components and 13% developed SBCE during median follow-up of 6.3 years. Compared to women with no MetS components, presence of MetS (≥3 components) was associated with increased risk of SBCE (HR = 1.50, 95% CI 1.08-2.07) and BC-specific mortality (HR = 1.65, 95% CI 1.02-2.69). Of the individual components, only increased weight was associated with increased risk of SBCE (HR = 1.26, 95% CI 1.06-1.49). MetS is associated with modestly increased risk of SBCE and BC-specific mortality. Given the growing population of BC survivors, further research in larger and more diverse populations is warranted.

Consumption of sweet foods and mammographic breast density: a cross-sectional study

BACKGROUND

The increasing consumption of sugar worldwide seems to lead to several health problems, including some types of cancer. While some studies reported a positive association between sweet foods intake and breast cancer risk, little is known about their relation to mammographic density (MD), a strong breast cancer risk factor. This study examined the association of sweet foods and drinks intake with MD among 776 premenopausal and 779 postmenopausal women recruited at mammography.

METHODS

A food-frequency questionnaire was used to assess intake of sweet foods, sugar-sweetened beverages and spoonsful of sugar added. Percent and absolute breast density were estimated using a computer-assisted method. Multivariate generalized linear models were used to evaluate associations. All models were adjusted for potential confounders, including age and body mass index.

RESULTS

For increasing quartiles of sugar-sweetened beverages intake, adjusted-mean absolute density was respectively 32, 34, 32 and 36 cm2 among all women (P(trend) = 0.040) and 43, 46, 44 and 51 cm2 among premenopausal women (P(trend) = 0.007). For increasing quartiles of sweet foods intake, adjusted-mean percent density was respectively 16, 16, 17 and 19% among postmenopausal women (P(trend) = 0.036). No association was shown between intake of spoonsful of sugar added and MD.

CONCLUSION

Our results suggest that an increase in sweet foods or sugar-sweetened beverage intake is associated with higher MD.

Association between insulin resistance and breast carcinoma: a systematic review and meta-analysis

Objective

This study was undertaken to evaluate the association between components defining insulin resistance and breast cancer in women.

Study Design

We conducted a systematic review of four databases (PubMed-Medline, EMBASE, Web of Science, and Scopus) for observational studies evaluating components defining insulin resistance in women with and without breast cancer. A meta-analysis of the association between insulin resistance components and breast cancer was performed using random effects models.

Results

Twenty-two studies (n = 33,405) were selected. Fasting insulin levels were not different between women with and without breast cancer (standardized mean difference, SMD −0.03, 95%CI −0.32 to 0.27; p = 0.9). Similarly, non-fasting/fasting C-peptide levels were not different between the two groups (mean difference, MD 0.07, −0.21 to 0.34; p = 0.6). Using individual odds ratios (ORs) adjusted at least for age, there was no higher risk of breast cancer when upper quartiles were compared with the lowest quartile (Q1) of fasting insulin levels (OR _{Q2 vs. Q1} 0.96, 0.71 to 1.28; OR _{Q3 vs. Q1} 1.22, 0.91 to 1.64; OR _{Q4 vs. Q1} 0.98, 0.70 to 1.38). Likewise, there were no differences for quartiles of non-fasting/fasting C-peptide levels (OR _{Q2 vs. Q1} 1.12, 0.91 to 1.37; OR _{Q3 vs. Q1} 1.20, 0.91 to 1.59; OR _{Q4 vs. Q1} 1.40, 1.03 to 1.92). Homeostatic model assessment (HOMA-IR) levels in breast cancer patients were significantly higher than in people without breast cancer (MD 0.22, 0.13 to 0.31, p<0.00001).

Conclusions

Higher levels of fasting insulin or non-fasting/fasting C-peptide are not associated with breast cancer in women. HOMA-IR levels are slightly higher in women with breast cancer.

Metabolic syndrome-breast cancer link varies by intrinsic molecular subtype

BACKGROUND

Metabolic syndrome (MS) has been shown to increase the risk of breast cancer. Existing data suggest that the strength of metabolic syndrome-breast cancer link varies by intrinsic molecular subtype, but results from worldwide literature are controversial. Primary endpoint of the study was to assess whether MS is a predictor of specific breast cancer (BC) subtype. Secondary endpoint was to determine whether components of MS can individually increase the risk of specific breast cancer subtype.

METHODS

Anthropometric and metabolic variables were correlated to breast cancer specific subgroups, retrospectively. Statistical significance was considered when p ≤ 0.05 and 95% CI.

RESULTS

Data analysis suggests that MS per se represents a modifiable risk factor for BC in postmenopausal [OR 6.28 (95% CI 2.79-14.11) p < 0.00001]. MS per se prevalence is higher among Luminal breast cancers in postmenopausal [OR 1.37 (95% CI 1.07-2.80) p = 0.03]. Body Mass Index (BMI) alone is associated to Luminal A subtype breast cancer risk [OR 1.12 (95% CI 0.96-2.196 p = 0.2]. Waist Circumference > 88 cm has been shown to be specifically and statistically significant associated to HER-2+ breast cancer subtypes in postmenopausal [OR 2.72 (95% CI 1.69- 10.72) p = 0.01], whilst in Luminal B it was only marginally statistical associated [OR 2.21 (95% CI 0.77-2.60) p = 0.1]. Insulin resistance showed statistical significant association to HER-2+ and Luminal B tumors [OR 2.11 (95% CI 1.66-6.69) p = 0.05] and [OR 2.33 (95% CI 1.2-4.2) p = 0.006], respectively. Hence, it has emerged that BMI is weakly associated to Luminal A breast cancers in this case series, whereas visceral obesity and insulin resistance are likely to be linked to more aggressive breast cancer subtypes.

CONCLUSIONS

New molecular biomarkers unveiling metabolic syndrome related breast carcinogenesis need to be detected to further stratify breast cancer risk by subtypes.

Insulin and IGF-I inhibit GH synthesis and release in vitro and in vivo by separate mechanisms

IGF-I is considered a primary inhibitor of GH secretion. Insulin may also play an important role in regulating GH levels because insulin, like IGF-I, can suppress GH synthesis and release in primary pituitary cell cultures and insulin is negatively correlated with GH levels in vivo. However, understanding the relative contribution insulin and IGF-I exert on controlling GH secretion has been hampered by the fact that circulating insulin and IGF-I are regulated in parallel and insulin (INSR) and IGF-I (IGFIR) receptors are structurally/functionally related and ubiquitously expressed. To evaluate the separate roles of insulin and IGF-I in directly regulating GH secretion, we used the Cre/loxP system to knock down the INSR and IGFIR in primary mouse pituitary cell cultures and found insulin-mediated suppression of GH is independent of the IGFIR. In addition, pharmacological blockade of intracellular signals in both mouse and baboon cultures revealed insulin requires different pathways from IGF-I to exert a maximal inhibitory effect on GH expression/release. In vivo, somatotrope-specific knockout of INSR (SIRKO) or IGFIR (SIGFRKO) increased GH levels. However, comparison of the pattern of GH release, GH expression, somatotrope morphometry, and pituitary explant sensitivity to acute GHRH challenge in lean SIRKO and SIGFRKO mice strongly suggests the primary role of insulin in vivo is to suppress GH release, whereas IGF-I serves to regulate GH synthesis. Finally, SIRKO and/or SIGFRKO could not prevent high-fat, diet-induced suppression of pituitary GH expression, indicating other factors/tissues are involved in the decline of GH observed with weight gain.

Homeostasis model assessment to detect insulin resistance and identify patients at high risk of breast cancer development: National Cancer Institute of Naples experience

BACKGROUND

Metabolic Syndrome (MS) has been correlated to breast carcinogenesis. MS is common in the general population (34%) and increases with age and body mass index. Although the link between obesity, MS and hormone related cancer incidence is now widely recognized, the molecular mechanisms at the basis of such increase are still poorly characterized. A crucial role is supposed to be played by the altered insulin signalling, occurring in obese patients, which fuels cancer cell growth, proliferation and survival. Therefore we focused specifically on insulin resistance to investigate clinically the potential role of insulin in breast carcinogenesis.

METHODS

975 patients were enrolled and the association between MS, insulin resistance, and breast cancer was evaluated. Women were stratified by age and menopausal status. Insulin resistance was measured through the Homeostasis Model Assessment score (HOMA-IR). The cut off value to define insulin resistance was HOMA-IR ≥ 2.50.

RESULTS

Higher prevalence of MS (35%) was found among postmenopausal women with breast cancer compared to postmenopausal healthy women (19%) [OR 2.16]. A broad range of BMI spanning 19-48 Kg/m2 was calculated. Both cases and controls were characterized by BMI ≥ 25 Kg/m2 (58% of cases compared to 61% of controls). Waist circumference >88 cm was measured in 53% of cases - OR 1.58- (95% CI 0.8-2.8) and in 46% of controls. Hyperinsulinemia was detected in 7% of cases - OR 2.14 (95% CI 1.78-2.99) and only in 3% of controls. HOMA-IR score was elevated in 49% of cases compared to 34% of controls [OR 1.86], suggesting that insulin resistance can nearly double the risk of breast cancer development. Interestingly 61% of women operated for breast cancer (cases) with HOMA-IR ≥ 2.5 presented subclinical insulin resistance with fasting plasma glucose levels and fasting plasma insulin levels in the normal range. Both android fat distribution and insulin resistance correlated to MS in the subgroup of postmenopausal women affected by breast cancer.

CONCLUSIONS

Our results further support the hypothesis that MS, in particular insulin resistance and abdominal fat, can be considered as risk factors for developing breast cancer after menopause. We suggest that HOMA-IR, rather than fasting plasma glucose and fasting plasma insulin levels alone, could be a valuable tool to identify patients with subclinical insulin resistance, which could be relevant for primary prevention and for high risk patient screening.

Risk factors for breast cancer and expression of insulin-like growth factor-2 (IGF-2) in women with breast cancer in Wuhan City, China

Purpose

The purpose of this study was to explore the risk factors for breast cancer and establish the expression rate of IGF-2 in female patients.

Methods

A case control study with 500 people in case group and 500 people in control group. A self-administered questionnaire was used to investigate risk factors for breast cancer. All cases were interviewed during a household survey. Immune-histochemical method was used to inspect the expression of IGF-2 in different tissues (benign breast lesions, breast cancer and tumor-adjacent tissue).

Results

Multivariate adjusted odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. High body mass index (OR = 1.012,95%CI = 1.008–1.016), working attributes (OR = 1.004, 95%CI = 1.002 = 1.006), long menstrual period (OR = 1.007, 95%CI = 1.005–1.009), high parity OR = 1.003, 95%CI = 1.001–1.005) , frequent artificial abortion (OR = 1.004, 95%CI = 1.001–1.005), family history of cancer (OR = 1.003, 95%CI = 1.000–1.005), period of night shift (OR = 1.003, 95%CI = 1.001–1.006), live in high risk environment (OR = 1.005, 95%CI = 1.002–1.008), and family problems (OR = 1.010, 95%CI = 1.005–1.014) were associated with increased risk for breast cancer. In this study, good sleeping status, positive coping strategies, subjective support, and utility degree of social support were associated with reduced risk for breast cancer (OR = 0.998, 0.997, 0.985, 0.998 respectively; 95%CI = 0.996–1.000, 0.994–1.000, 0.980–0.989, 0.996–1.000, respectively). In benign breast lesions, breast cancer and tumor-adjacent tissue, IGF-2 was mainly expressed in the cytoplasm, but its expression rate was different (p<0.05).

Conclusions

The incidence of breast cancer is a common result of multiple factors. IGF-2 is involved in the development of breast cancer, and its expression varies in different tissues (benign breast lesions, breast cancer and tumor-adjacent tissue).

Common genetic variation within IGFI, IGFII, IGFBP-1, and IGFBP-3 and endometrial cancer risk

OBJECTIVE

The insulin-like growth factor (IGF) pathway plays a critical role in the growth and development of the uterus and is believed to function as a mediator of steroid hormone actions in the endometrium. The local expression of genes encoding IGFs and IGF-binding proteins (IGFBPs) is important in determining IGF bioactivity in the uterus. Genetic variation in key genes within the IGF pathway may influence the rate of cellular proliferation and differentiation in the uterus and ultimately affect the risk of endometrial cancer. Our hypothesis is that variant alleles in key genes involved in the IGF pathway will influence the development of endometrial cancer.

METHODS

We conducted a case-control study nested within the Nurses' Health Study (NHS) and the Women's Health Study (WHS) to investigate the association between forty-four polymorphisms within IGFI, IGFII, IGFBP-1, and IGFBP-3 with endometrial cancer risk using 692 invasive endometrial cancer cases and 1723 matched controls. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) to assess the risk of endometrial cancer.

RESULTS

We observed an inverse association with IGFII rs3741211 and endometrial cancer risk (OR=0.79 (95% CI: 0.63, 0.99)) and IGFII rs1004446 and endometrial cancer risk (OR=0.80 (95% CI: 0.68, 0.94)). We also observed an inverse association with IGFBP-3 rs2453839 and endometrial cancer risk (OR=0.81 (95%CI: 0.67, 0.98). However, we did not observe any statistically significant associations with the polymorphisms in IGFI and IGFBP1 and endometrial cancer risk.

CONCLUSIONS

Genetic variation with IGFII and IGFBP-3 may influence endometrial cancer risk in Caucasians. Polymorphisms in IGFI and IGFBP-1 were not associated with endometrial cancer risk, but further research is needed.

Carbohydrate intake, glycemic load, glycemic index, and risk of ovarian cancer

BACKGROUND

Our objective was to determine the relationship between dietary glycemic load (GL), glycemic index (GI), carbohydrate intake, and ovarian cancer risk in a population-based case-control study.

PATIENTS AND METHODS

A self-administered questionnaire was used to collect data on demographic and lifestyle factors, and a food frequency questionnaire was used to collect dietary information from 1366 women with ovarian cancer and 1414 population controls.

RESULTS

GL was positively associated with ovarian cancer. The adjusted odds ratio (OR) for the highest versus the lowest quartile of intake was 1.24 [95% confidence interval (CI) 1.00-1.55, P for trend = 0.03]. Fiber intake was inversely associated with risk. The OR comparing women in the highest fiber-intake group with those in the lowest was 0.78 (95% CI 0.62-0.98, P for trend = 0.11). We found no association between GI, carbohydrate intake, and ovarian cancer. In analyses stratified by body mass index, the risk estimates for GL, carbohydrate, and sugar were higher among overweight/obese women; however, the interaction term was only significant for sugar (P for interaction = 0.004).

CONCLUSIONS

Our results suggest that diets with a high GL may increase the risk of ovarian cancer, particularly among overweight/obese women, and a high intake of fiber may provide modest protection.

Identification of proteins secreted from leptin stimulated MCF-7 breast cancer cells: a dual proteomic approach

Leptin is an adipocyte-derived hormone that regulates energy expenditure and food intake. A significant role for leptin in breast cancer has also been indicated by the resistance of leptin knockout mice in development of mammary tumors. In vitro, leptin induces proliferation of MCF-7 cells by activating cellular signaling pathways (1, 11, 12, 16, 17, 56). As leptin is emerging as an important factor for tumor growth, and hormones can exert their actions via autocrine/paracrine mechanisms, we hypothesized leptin may act by regulating epithelial-derived proteins. To test this hypothesis, leptin-regulated proteins secreted from MCF-7 mammary tumor cells were identified using proteomics techniques. Treatment of MCF-7 cells with 500 ng/ml leptin for 24 hours resulted in a 40% increase in cell number and a 5-fold increase in protein secretion as compared to controls. Establishing the significance of leptin-induced secreted factors, the addition of conditioned media from leptin-treated MCF-7 cells to synchronized MCF-7 cells resulted in 40% increase in cell number. Identification of leptin-regulated secreted proteins was done by 2D gel electrophoresis coupled with MALDI-TOF mass spectrometry. Proteins identified using Pro Found software and NCBI database included KF10 Collagen Precursor, Serologically Defined Breast Cancer Antigen NY-BR-62 and Cortactin Isoform a. A Human Cytokine Antibody Array system was used to identify low abundant proteins in the media of control and 500 ng/ml leptin-stimulated MCF-7 cells. In leptin treated cells, levels of FGF-9 were increased while IGFBP-3 and TGF-beta3 levels were decreased. Many previous studies have focused on the regulation of distinct cellular proteins by leptin during mammary tumor cell proliferation. However, ours is the first study to identify leptin-regulated secreted proteins, many of which are known to play important roles in cancer. Our data support that leptin can influence mammary tumor growth and progression through regulation of autocrine/paracrine factors and by modulating the extracellular matrix composition.

Glycemic Load, Glycemic Index, and the Risk of Breast Cancer Among Mexican Women

OBJECTIVE

The amount and composition of dietary carbohydrates is a major determinant of postprandial blood glucose and insulin, and risk of breast cancer has been positively associated with plasma levels of insulin and insulin-like growth factor 1. We sought to evaluate dietary glycemic load (GL) and overall glycemic index (GI) in relation to breast cancer risk in Mexican women.

METHODS

We examined dietary GL and overall GI and breast cancer risk among 475 women with histologically-confirmed breast cancer and a random sample of 1391 women from Mexico City households. Diet was assessed using a food frequency questionnaire adapted to the Mexican population.

RESULTS

The multivariate adjusted or for all women comparing the highest quartile of dietary GL with the lowest quartile was 1.62 (95% CI 1.13-2.32; p-test for trend = 0.02) with a significant trend. In postmenopausal women, the multivariate adjusted or comparing the extreme quartiles was 2.18 (95% CI 1.34-3.55; p-test for trend=0.005). Overall GI was not significantly associated with risk of breast cancer.

CONCLUSION

High intake of rapidly absorbed carbohydrate appears to play an important role in the risk of breast cancer in Mexican women.

Comorbidity as a predictor of stage of illness for patients with breast cancer

OBJECTIVE

The purpose of this research was to determine whether comorbidity affects the stage at which breast cancer is diagnosed.

METHODS

Data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI) was merged with Medicare claims for 17,468 women diagnosed with breast cancer from 1993 to 1995.

RESULTS

Women with cardiovascular disease, musculoskeletal disorders, mild-to-moderate gastrointestinal disease, and nonmalignant benign breast disease had a 13%, 7%, 14%, and 24% lower odds, respectively, of being diagnosed with advanced breast cancer. Women with diabetes, other endocrine disorders, psychiatric disorders, or hematologic disorders increased the odds of a late-stage diagnosis by 19%, 11%, 20%, and 19% respectively. Mammography screening and contact with the medical care system decreased the odds of late-stage diagnosis.

DISCUSSION

Four hypotheses are suggested to explain this link between comorbid illness and stage at diagnosis: (1) the "surveillance" hypothesis, (2) the "physiological" hypothesis, (3) the "competing demand" hypothesis, and (4) the "death from other causes" hypothesis.

CONCLUSIONS

Comorbidity may complicate the diagnostic decision-making process for breast cancer. The results suggest that contact with the medical care system improves the odds of early-stage diagnosis. Thus, barriers to access for people with chronic conditions may exacerbate those chronic conditions and increase the odds of late-stage breast cancer.

Polycystic ovary syndrome and gynecological cancers: is there a link?

Polycystic ovary syndrome [PCOS] is the most common endocrinopathy of women in reproductive age. An association between PCOS and type-1 endometrial cancer has often been reported in the literature. The prolonged anovulation with consequent continued secretion of estrogen unopposed by progesterone may enhance the development and growth of this malignancy, particularly in young women. Hypersecretion of luteinizing hormone [LH], chronic hyperinsulinemia and increased serum insulin-like growth factor [IGF]-I levels may represent risk factors for endometrial cancer. However, data available in the literature do not allow a meta-analysis to be carried out to calculate an estimate of the relative risk of endometrial cancer in women with PCOS. Anecdotal cases of low-grade endometrial stromal sarcoma and carcinosarcoma have been reported in association with prolonged unopposed estrogen stimulation, and in particular with PCOS. A few studies have addressed the possibility of an association between PCOS and epithelial ovarian cancer risk, and the results are conflicting but generally reassuring, and similarly the few available data appear to exclude a strong association between PCOS and breast cancer.

Carbohydrates and the Risk of Breast Cancer among Mexican Women

Objective: High carbohydrate intake has been hypothesized to be a risk factor for breast cancer, possibly mediated by elevated levels of free insulin, estrogens, and insulin-like growth factor-1. Therefore, we conducted a population-based case-control study among a Mexican population characterized by relatively low fat and high carbohydrate intakes. Methods: Women ages 20 to 75 years, identified through six hospitals in Mexico City (n = 475), were interviewed to obtain data relating to diet (using a food frequency questionnaire) and breast cancer risk factors. Controls (n = 1,391) were selected from the Mexico City population using a national sampling frame. Results: Carbohydrate intake was positively associated with breast cancer risk. Compared with women in the lowest quartile of total carbohydrate intake, the relative risk of breast cancer for women in the highest quartile was 2.22 [95% confidence interval (95% CI) 1.63-3.04], adjusting for total energy and potential confounding variables (P for trend &lt; 0.0001). This association was present in premenopausal and postmenopausal women (for highest versus lowest quartile, odds ratio 2.31, 95% CI 1.36-3.91 in premenopausal women and odds ratio 2.22, 95% CI 1.49-3.30 in postmenopausal women). Among carbohydrate components, the strongest associations were observed for sucrose and fructose. No association was observed with total fat intake. Discussion: In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk. This relation deserves to be investigated further, particularly in populations highly susceptible to insulin resistance.

Differential effects of progestins on the circulating IGF-I system

OBJECTIVE

Circulating insulin-like growth factor-I (IGF-I) is mainly produced by the liver under GH stimulation and is influenced by nutrition and insulin. IGF-I bioavailability is regulated by interactions with specific binding proteins (IGFBPs). The objective of this paper is to review available data on modifications of the IGF-I system in menopausal women during HRT, with particular attention on the differential effects of progestins.

METHOD

All available reports on the effects of different forms of HRT have been taken into account.

RESULTS

Available data suggest that different kinds of HRT have different effect on the IGF-I system, depending on route of administration, oestrogen dose, basal IGF-I values and type of progestin. Oestrogen administration (oestrogen replacement therapy (ERT)) reduces circulating IGF-I mainly through a hepatocellular effect. The decrease is sharper when oral ERT is used (first pass hepatic effect) and in women with higher basal IGF-I levels. The progestins endowed with androgenic effects--the 19-nortestosterone derivatives and, to a lesser extent, medroxyprogesterone acetate (MPA)--tend to reverse the IGF-I decrease induced by oral oestrogens. In contrast, progestins devoid of androgen-like hepatocellular and metabolic actions (e.g. dydrogesterone) do not interfere with the IGF-I decrease induced by oral oestrogens. Data on the effect of ERT on IGFBP-3 level are not consistent. Oral ERT, via hepatocellular actions (amplified by the first pass hepatic effect) causes a two to three-fold increase in IGFBP-1 levels. Androgenic progestins oppose the IGFBP-1 increase induced by oral oestrogens. Data on the effect of ERT and different progestins on the level of free IGF-I are scant and inconsistent.

CONCLUSION

Even if some aspects need clarification, available data demonstrate that different progestins have differential effects on the circulating IGF-I system.