Adalberto Cavalleri

Urinary 6-Sulfatoxymelatonin Levels and Risk of Breast Cancer in Postmenopausal Women

BACKGROUND Low urinary melatonin levels have been associated with an increased risk of breast cancer in premenopausal women. However, the association between melatonin levels and breast cancer risk in postmenopausal women remains unclear. METHODS We investigated the association between melatonin levels and breast cancer risk in postmenopausal women in a prospective case-control study nested in the Hormones and Diet in the Etiology of Breast Cancer Risk cohort, which included 3966 eligible postmenopausal women. The concentration of melatonins major metabolite, 6-sulfatoxymelatonin, was measured in a baseline 12-hour overnight urine sample from 178 women who later developed incident breast cancer and from 710 matched control subjects. We used multivariable-adjusted conditional logistic regression models to investigate associations. Relative risks are reported as odds ratios (ORs). All statistical tests were two-sided. RESULTS Increased melatonin levels were associated with a statistically significantly lower risk of invasive breast cancer in postmenopausal women (for women in the highest quartile of total overnight 6-sulfatoxymelatonin output vs the lowest quartile, multivariable OR also adjusted for testosterone = 0.56, 95% confidence interval [CI] = 0.33 to 0.97; P(trend) = .02). This association was strongest among never and past smokers (OR = 0.38, 95% CI = 0.20 to 0.74; P(trend) = .001) and after excluding women who were diagnosed with invasive breast cancer within 4 years after urine collection (OR = 0.34, 95% CI = 0.15 to 0.75; P(trend) = .002). We did not observe substantial variation in relative risks by hormone receptor status of breast tumors. Among the 3966 women in the cohort, 40 of the 992 women in the highest quartile of 6-sulfatoxymelatonin developed breast cancer during follow-up, compared with 56 of the 992 women in the lowest quartile of 6-sulfatoxymelatonin. CONCLUSION Results from this prospective study provide evidence for a statistically significant inverse association between melatonin levels, as measured in overnight morning urine, and invasive breast cancer risk in postmenopausal women.

Testosterone, dihydrotestosterone and oestradiol levels in postmenopausal breast cancer tissues

The ability of breast tumours to synthesize hormones is well recognized, and local production of sex steroids is thought to play a role in breast cancer growth. We measured the intratumour and circulating levels of testosterone, dihydrotestosterone (DHT) and oestradiol in 35 histologically confirmed carcinomatous mammary tissues obtained at breast surgery from 34 postmenopausal patients, age 50-85 years. Intra-tissue steroids were extracted with ethanol:acetone (1:1; v/v), defatted with 70% methanol in water, and extracted with ether. Steroids, from tissue and serum, were separated by partition chromatography on celite columns and were measured by RIA. Intratumour testosterone and DHT concentrations were significantly correlated, after the exclusion of an outlier (rs = 0.71; P = 0.0001). No association was found between oestradiol and either of the two androgens. Mean oestradiol and DHT concentrations were significantly higher in tissue than in blood (P = 0.0001). Mean testosterone levels in tissues did not significantly differ from those measured in blood. Our data suggest that at least a part of intratissue DHT is produced locally from testosterone. The meaning of high oestradiol and DHT levels in cancer tissue still needs to be defined.

Urinary 6-Sulphatoxymelatonin Levels and Risk of Breast Cancer in Premenopausal Women: The ORDET Cohort

Background: Lower urinary melatonin levels are associated with a higher risk of breast cancer in postmenopausal women. Literature for premenopausal women is scant and inconsistent. Methods: In a prospective case-control study, we measured the concentration of 6-sulphatoxymelatonin (aMT6s) in the 12-hour overnight urine of 180 premenopausal women with incident breast cancer and 683 matched controls. Results: In logistic regression models, the multivariate odds ratio (OR) of invasive breast cancer for women in the highest quartile of total overnight aMT6s output compared with the lowest was 1.43 [95% confidence interval (CI), 0.83-2.45; Ptrend = 0.03]. Among current nonsmokers, no association was existent (OR, 1.00; 95% CI, 0.52-1.94; Ptrend = 0.29). We observed an OR of 0.68 between overnight urinary aMT6s level and breast cancer risk in women with invasive breast cancer diagnosed >2 years after urine collection and a significant inverse association in women with a breast cancer diagnosis >8 years after urine collection (OR, 0.17; 95% CI, 0.04-0.71; Ptrend = 0.01). There were no important variations in ORs by tumor stage or hormone receptor status of breast tumors. Conclusion: Overall, we observed a positive association between aMT6s and risk of breast cancer. However, there was some evidence to suggest that this might be driven by the influence of subclinical disease on melatonin levels, with a possible inverse association among women diagnosed further from recruitment. Thus, the influence of lag time on the association between melatonin and breast cancer risk needs to be evaluated in further studies. Cancer Epidemiol Biomarkers Prev; 19(3); 729–37

Plasma Testosterone and Prognosis of Postmenopausal Breast Cancer Patients

PURPOSE High endogenous testosterone is associated with increased breast cancer (BC) risk. We designed this study specifically to assess the long-term prognostic role of testosterone in a cohort of postmenopausal BC patients. PATIENTS AND METHODS We considered 194 postmenopausal women, operated on for early BC (T1-2N0M0), who never received chemotherapy or hormonal therapy, and who participated in a fenretinide BC prevention trial as untreated controls. Blood samples were collected 3 months (median) after surgery; plasma samples, stored at -80 degrees C, were radioimmunoassayed for testosterone. Median follow-up was 14 years. The main end point was any cancer event. Event-free survival was estimated by the Kaplan-Meier method. Hazard ratios (HRs) of events by testosterone level were estimated by the Cox model, adjusting for age, tumor size, and histology. RESULTS Patients with high testosterone (> or = 0.40 ng/mL, median of distribution) had significantly lower event-free survival than those with low testosterone (log-rank P = .004). The adjusted HR of patients with high versus low testosterone was 2.05 (95% CI, 1.28 to 3.27). High testosterone was also associated with a significantly higher risk of BC events (relapse and second primary) with an adjusted HR of 1.77 (95% CI, 1.06 to 2.96). Eleven second primaries (non-BC) occurred in the high-testosterone group, four in the low-testosterone group. CONCLUSION High plasma testosterone strongly predicts poorer prognosis in postmenopausal BC patients not administered adjuvant therapy. Testosterone levels should be determined as part of the prognostic work-up.

Methods for urinary testosterone analysis.

Urinary testosterone analysis requires a multistep procedure to achieve a good degree of sensitivity and specificity in the dosage. Hydrolysis, extraction, purification and quantification are usually performed in sequence, and several options can be chosen for each of them. After introductory remarks on the applications of urinary testosterone measurement and a short description of the metabolic pathway of the hormone, an overview of the techniques most commonly used in each step is presented. Advantages and disadvantages of each of them are outlined, and a procedure for urinary testosterone analysis is suggested. The procedure consists of: enzymatic hydrolysis with Helix pomatia juice, followed by solid-phase extraction of hydrolyzed urine by a C18 cartridge coupled with an NH2 cartridge and high-performance liquid chromatography cleanup of the extract. Then, quantification can be achieved by gas chromatography or radioimmunoassay.

Equol Status Modifies the Association of Soy Intake and Mammographic Density in a Sample of Postmenopausal Women

Only 30% to 50% of people produce the daidzein-metabolite equol after eating soy. We conducted a cross-sectional study of the associations between equol status, intake of soy foods, and mammographic density in a sample of postmenopausal women recruited at a radiology clinic near Buffalo, New York. Participants were 48 to 82 years old, had no history of cancer or breast reduction/augmentation, and no recent use of antibiotics or hormones. Percent density was measured by computer-assisted analysis of digitized images of craniocaudal films. Equol status was assessed using a soy-challenge protocol and usual soy intake by questionnaire. General linear models were used to assess independent and joint effects of equol status and intake of soy on multivariate adjusted percent density (covariates included age, body mass index, parity, age at first birth, and ever use of combined hormone therapy). Of 325 enrolled, 232 (71%) participants completed study assessments and are included in the present analysis. Mean percent density was 34% (±18%). Seventy-five (30%) participants were producers of equol. Forty-three (19%) participants reported regularly eating >1 soy food or supplement/wk. There were no significant independent associations of equol status or soy intake with percent density, but the interaction between these factors was significant (P < 0.01). Among equol producers, those with weekly soy intake had lower percent density (30.7% in weekly consumers of soy versus 38.9% in others; P = 0.08); among nonproducers, weekly soy intake was associated with higher percent density (37.5% in weekly soy consumers versus 30.7% in others; P = 0.03). Results suggest that equol producers and nonproducers may experience different effects of dietary soy on breast tissue. (Cancer Epidemiol Biomarkers Prev 2008;17(1):33–42)

Evaluation of reactive oxygen metabolites in frozen serum samples. Effect of storage and repeated thawing

Measuring the free radical activity in serum samples from prospective studies is the best way to investigate the association between oxidative stress and human diseases. Prospective studies require the analysis of serum samples that have often been stored for a long time. Our study was designed to determine the effect of storage at -30 degrees C and -80 degrees C for two years on free radical activity. We analyzed the free radical activity by measuring circulating hydroperoxides in a pool of sera at baseline and after one day, one week, one month and 25 months of storage, using a photometric method (d-ROMs test). Measurements were performed in aliquots thawed only once at each time point and in aliquots frozen and thawed repeatedly over the study period. After two years we observed a small but statistically significant 4% decrease in the hydroperoxide concentration, which was substantially unaffected by storage temperatures and repeated freeze-thaw cycles. We also carried out the d-ROMs test in sera from ten apparently healthy volunteers at 2, 8, 24, and 48 hours after collection and storage at 4 degrees C and did not observe any significant variation. In conclusion, the d-ROMs test is a simple method suitable to evaluate the free radical activity in frozen serum samples after long-term storage.

Testosterone and Biological Characteristics of Breast Cancers in Postmenopausal Women

Androgens are involved in the development of breast cancer, although the mechanisms remain unclear. To further investigate androgens in breast cancer, we examined the relations between serum testosterone and age, body mass index (BMI), tumor size, histologic type, grade, axillary node involvement, estrogen receptor status, progesterone receptor status, and HER2 overexpression in a cross-sectional study of 592 postmenopausal breast cancer patients. Mean testosterone differences according to categories of patient and tumor characteristics were assayed by Fishers or Kruskall-Wallis test as appropriate; adjusted odds ratios (OR) of having a tumor characteristic by testosterone tertiles were estimated by logistic regression. Testosterone concentrations were significantly higher in women with BMI ≥30 versus BMI <25. ORs of having a tumor ≥2 cm increased significantly with increasing testosterone tertiles, and the association was stronger in women ≥65 years. The OR of having infiltrating ductal carcinoma was significantly higher in the highest compared with the lowest testosterone tertile. ORs of having estrogen receptor– and progesterone receptor–negative versus estrogen receptor– and progesterone receptor–positive tumors decreased significantly with increasing testosterone tertiles. In women ≥70 years, those with high testosterone had a significantly greater OR of HER2-negative cancer than those with low testosterone. These results support previous findings that high-circulating testosterone is a marker of hormone-dependent breast cancer. The age-related differences in the association of testosterone with other disease and patient characteristics suggest that breast cancers in older postmenopausal women differ markedly from those in younger postmenopausal women. The relationship between testosterone and HER2 status in the oldest patients merits further investigation. (Cancer Epidemiol Biomarkers Prev 2009;18(11):2942–8)

Plasma Riboflavin and Vitamin B-6, but Not Homocysteine, Folate, or Vitamin B-12, Are Inversely Associated with Breast Cancer Risk in the European Prospective Investigation into Cancer and Nutrition-Varese Cohort

BACKGROUND One-carbon metabolism-important for DNA stability and integrity-may play a role in breast carcinogenesis. However, epidemiologic studies addressing this issue have yielded inconsistent results. OBJECTIVE We prospectively investigated associations between breast cancer and plasma folate, riboflavin, vitamin B-6, vitamin B-12, and homocysteine in women recruited to the Varese (Italy) cohort of the EPIC (European Prospective Investigation into Cancer and Nutrition) study. METHODS We performed a nested case-control study on women aged 35-65 y at recruitment with a median body mass index of 25.3 kg/m(2) who gave blood samples in 1987-1992 and again in 1993-1998. Breast cancer cases identified by 31 December 2009 were individually matched to controls. RRs of breast cancer (and subtypes defined by hormone receptor status) with 95% CIs were estimated by unconditional logistic regression, controlling for matching factors and breast cancer risk factors. RESULTS After a median of 14.9 y, 276 breast cancer cases were identified and matched to 276 controls. Increasing plasma vitamin B-6 was associated with decreased risk of overall (RR: 0.78; 95% CI: 0.63, 0.96 for 1-SD increase), premenopausal (RR: 0.66; 95% CI: 0.48, 0.92 for 1-SD increase), estrogen receptor-positive (RR: 0.79; 95% CI: 0.63, 1.00 for 1-SD increase), and progesterone receptor-positive (RR: 0.72; 95% CI: 0.55, 0.95 for 1-SD increase) breast cancers. Increased plasma vitamin B-6 was also associated with decreased breast cancer risk in alcohol consumers (≥7 g/d) compared with consumption of <7 g/d or nonconsumption (RR: 0.71; 95% CI: 0.51, 0.99). High plasma riboflavin was associated with significantly lower risk in premenopausal women (RR: 0.45; 95% CI: 0.21, 0.94; highest compared with the lowest quartile, P trend = 0.021). Plasma homocysteine, folate, and vitamin B-12 were not associated with breast cancer risk. CONCLUSIONS High plasma vitamin B-6 and riboflavin may lower breast cancer risk, especially in premenopausal women. Additional research is necessary to further explore these associations.

Circulating sex hormones and tumor characteristics in postmenopausal breast cancer patients. A cross-sectional study

Background To further investigate the role of sex hormones in breast cancer, we assessed the relations of circulating estradiol and testosterone to tumor size and estrogen receptor (ER) status. Method This was a cross-sectional study including 492 postmenopausal breast cancer patients. The relation of circulating hormones to patient and tumor characteristics was assessed using the Fisher or Cuzick tests. Multivariable logistic regression was used to estimate the odds ratios (ORs) of having tumors ≥2 cm (vs <2 cm) and having ER-positive tumors (vs ER-negative) with increasing quartiles of estradiol and testosterone. Results Mean estradiol and testosterone levels increased significantly with increasing tumor size. The ORs of tumors ≥2 cm increased significantly with increasing quartiles of estradiol (Ptrend<0.001) and testosterone (Ptrend=0.005). When adjusted for estradiol, the association between testosterone and tumor size was no longer significant. Mean testosterone levels were higher in ER-positive than ER-negative patients (P<0.001), while mean estradiol levels did not differ significantly between the two ER categories (p=0.192). The ORs of having an ER-positive tumor increased significantly with increasing quartiles of testosterone (Ptrend=0.002), whereas the increase with increasing estradiol quartiles was not significant (Ptrend=0.07). Conclusion The association of both hormones with tumor size implies that both are involved in tumor growth, testosterone mainly by conversion to estradiol. The strong association of testosterone with ER contrasts with the weak association of estradiol with ER and confirms testosterone as a marker of hormone-dependent tumors. These findings suggest that testosterone evaluation might be useful to better identify patients with hormone-dependent disease.