Abstract P6-09-02: Risk of Breast Cancer Associated with Hormone Replacement Therapy Use Differs by Age, Race, and Breast Density

Background: Observational studies and randomized trials have demonstrated an association between hormone replacement therapy (HRT) use and increased risk for breast cancer. However, this risk may vary by age and other factors, including breast density and race/ethnicity. Using data from the Breast Cancer Surveillance Consortium (BCSC), we investigate whether self-reported HRT use in the peri-menopausal and immediate post-menopausal age groups is associated with breast cancer, and also whether risk associated with HRT use differs by breast density and race. Subjects and Methods: The BCSC is a longitudinal registry of mammography screening in seven U.S. centers. In the breast cancer risk prediction model developed by Barlow et al (J Natl Cancer Inst 2006 98:1204-14), HRT use and ten other features were identified as risk factorsfor breast cancer. Data for our study consists of 1,642,824 screens and 9,300 breast cancers among the post-menopausal women aged > 44 in this cohort. Logistic regression models were used to estimate odds ratios for breast cancer associated with HRT use within race, age, and density strata, adjusting for other variables from the Barlow model. Multiple imputation methods were used to accommodate missing data for HRT (14%) and other predictors.

Results: Breast cancer risk for HRT use varied by age, with no risk excess among women aged 45-49 and risk excess of 20% or greater for women aged 50-64 (Table 1). Women >64 had a smaller excess risk with HRT use. There was no significant excess risk at any age for Black women, while White women age 50-64 had > 20% excess risk for HRT use. White women with higher breast density had increased risk with HRT use, while Black women did not.

Table 1: Odds ratios (95% confidence interval) for HRT use (yes/no)

Conclusions: In this large cohort of mammography-screened women, HRT use did not increase breast cancer risk in the peri-menopausal period (age 45-49). Women with low breast density had smaller risk increments associated with HRT than those with high density. For Black women, increased breast cancer risk due to HRT was not apparent at any age or breast density category.

Data collection for the BCSC was supported by a NCI-funded Breast Cancer Surveillance Consortium co-operative agreement (U01CA63740, U01CA86076, U01CA86082, U01CA63736, U01CA70013, U01CA69976, U01CA63731, U01CA70040).

Greenland ice evidence of hemispheric lead pollution two millennia ago by greek and roman civilizations

Analysis of the Greenland ice core covering the period from 3000 to 500 years ago-the Greek, Roman, Medieval and Renaissance times-shows that lead is present at concentrations four times as great as natural values from about 2500 to 1700 years ago (500 B.C. to 300 A.D.). These results show that Greek and Roman lead and silver mining and smelting activities polluted the middle troposphere of the Northern Hemisphere on a hemispheric scale two millennia ago, long before the Industrial Revolution. Cumulative lead fallout to the Greenland Ice Sheet during these eight centuries was as high as 15 percent of that caused by the massive use of lead alkyl additives in gasoline since the 1930s. Pronounced lead pollution is also observed during Medieval and Renaissance times.

Leukocyte membrane bleb and pseudopod formation in hypertension

Leukocyte activation, including adhesion molecule expression, oxygen radical generation and, in animal studies, pseudopod formation, is a hallmark of hypertension. This study examined pseudopod and bleb formation and demonstrates that leukocytes from hypertensive individuals are more susceptible to produce membrane blebs than leukocytes from normotensive individuals. Bleb formation is likely indicative of apoptosis, thus this observation adds to previous observations of increased apoptosis in various tissues in hypertension.

71 DEVELOPMENT OF CLONED DOG EMBRYOS RECONSTRUCTED WITH PRE-ACTIVATED IN VIVO OOCYTES AND DONOR FIBROBLASTS ARRESTED AT G2/M PHASE USING ROSCOVITINE

The coordination between the cell cycle stages of nuclear donor cells and host oocytes has a critical effect on the development of embryos produced by somatic cell nuclear transfer (SCNT). Here, we investigated (1) whether roscovitine, an inhibitor of cyclin-dependent kinases (CDK) could arrest canine somatic cells at S/G2 phase of the cell cycle; (2) whether IVM metaphase II (MII) oocyte could be induced to telophase II (TII) after activation. Last, we investigated embryo development ability of nonactivated oocytes (MII) or activated oocytes (TII) fused with somatic cells at different stages of the cell cycle. Dog fetal fibroblasts were treated with roscovitine (30 or 60 μg mL-1 at 24, 48, or 72 h) and a control group of donor cells was cultured to reach confluency. The cells were then fixed and stained with 1 mg mL-1 propidium iodide for flow cytometric analysis. For SCNT, IVM dog oocytes were obtained by flushing (approximately 72 h after ovulation) from the oviducts of oocyte donor dog (Canis familiaris) and divided into 2 groups; nonactivated oocytes (MII) and activated oocytes (TII) by 10 μg mL-1 calcium ionophore for 4 min. Following preparation of each donor cell arrested in G0 and G2/M phase, cells of G0 stage were placed into enucleated MII oocytes (MII-G0) and cells of G2/M-phase were placed into enucleated TII oocytes (TII-G2/M). After fusion by electric stimulation, the MII-G0 group was chemically activated and cultured in modified SOF medium (mSOF), and the TII-G2/M group was cultured in mSOF without activation. The embryo developmental competence was estimated by assessing in vitro development under the microscope. Data were analyzed using a statistical analysis system program. Based on flow cytometry, the frequency of cells arrested at G2/M-phase in the 30 and 60 μg mL-1 roscovitine groups was significantly higher than that in control (31.95 and 25.99% v. 19.79%, respectively), but differences were not observed between the 30 and 60 μg mL-1 roscovitine groups (P > 0.05). Also, a significant increase in the proportion of cells at G2/M-phase was observed at 48 and 72 h in both roscovitine groups compared with the group not treated with roscovitine. The proportion of cells at G2/M-phase in the 60 μg mL-1 group at 48 h and the 30 μg mL-1 group at 72 h was the highest among all treatments. For the TII-G2/M group, we injected into enucleated TII oocyte and selected a large cell that arrested at G2/M-phase in cells cultured with 60 μg mL-1 roscovitine for 48 h. For the result of in vitro development of cloned embryo from MII-G0 and TII-G2/M, TII-G2/M group (39.4 and 7.8%) showed an increased cleavage rate and development to 8 cells compared with MII-G0 (23.5 and 2.9%). In the present study, we demonstrated that, in combination with nuclear donor cells at specific cell cycle stages, MII and TII dog oocytes are similarly effective in supporting the reprogramming of somatic cell nuclei. This study was supported by Korean MEST through KOSEF (grant # M10625030005-09N250300510) and BK21 program, RNL BIO, and Natural Balance Korea.

The Effect of Preoperative MRI on Mastectomy Rates in Breast Cancer Patients

Background: Currently, there are two primary surgical options for the treatment of early stage breast cancer: modified radical mastectomy and breast conserving surgery (BCS) with post-surgical radiation. Numerous studies have shown that there is no survival difference between the two surgical treatments, however, in recent years, there is data to suggest that mastectomy rates have been on the rise. While many factors undoubtedly influence surgical management decisions in breast cancer patients, the effect of routine use of preoperative breast MRI may be a contributor to the rise in mastectomy rates. Methods: Breast cancer patients who were treated surgically and received a preoperative MRI were identified using a database from the University of Chicago Department of Radiology, which contains information on over 4200 patients who have received breast MRI since 2002. These patients were cross-referenced with data from the University of Chicago Cancer Registry, which contains information regarding type of surgical treatment, surgeon, stage of cancer at time of diagnosis and surgical stage for all breast cancer patients treated at the University of Chicago Hospitals from 2000-2007. Annual mastectomy rates from 2000-2007 were calculated and compared using Pearson's Chi Square test. Annual mastectomy rates were stratified by mean age at diagnosis and stage of disease. Mastectomy rates prior to routine use of preoperative MRI (2000-2002) and after routine use of preoperative MRI (2005-2007) were calculated for breast cancer patients under 45 and over 45 years of age and rates were compared using Fisher's exact test. Results: A total of 1,404 patients received surgical treatment for a new diagnosis of breast cancer between 2000 and 2007 at the University of Chicago Hospitals. Results to date indicate that mastectomy rates across all years are not significantly different (p = 0.315). Results also indicate that the mean age at diagnosis of patients who receive mastectomy as the initial surgical treatment for their breast cancer is higher than those who receive BCS from 2000-2002, but is lower than those who receive BCS from 2003-2007. In addition, breast cancer patients under the age of 45 have higher rates of mastectomy since the routine use of preoperative MRI which trends toward statistical significance (p = 0.0598). Conclusion: These preliminary results indicate that overall mastectomy rates at the University of Chicago Hospitals are not increasing in concordance with the increased use of preoperative MRI testing, but that younger breast cancer patients may have higher rates of mastectomy in the MRI era.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4019.

A cross-sectional study of dentine hypersensitivity in China

OBJECTIVE

To carry out a cross-sectional study of the prevalence of dentine hypersensitivity and related risk factors in Chengdu City, China.

METHODS

A total of 1,320 subjects were distributed equally in six communities in Chengdu City and of all age groups (10 years for an age group) including the same number of male and female subjects in each community. Each subject completed a structured interview and the subjects who reported hypersensitivity were examined further using a triple syringe to administer a blast of cold air to confirm the diagnosis of dentine hypersensitivity. Periodontal attachment loss and gingival recession of all sensitive teeth were measured.

RESULTS

The prevalence of dentine hypersensitivity was 25.5% in the oral test. Only 16.6% of subjects who reported hypersensitivity symptoms had received desensitising treatment. 50-59 year age group was the cohort with the greatest number of subjects with DH and the premolar was the most commonly affected tooth. Low education level, gingival recession, and attachment loss were related to dentine hypersensitivity.

CONCLUSIONS

The prevalence of dentine hypersensitivity in an urban adult population in Chengdu City was 25.5%.