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Background: This study aimed to investigate the distribution and changes of HER2 status in untreated tumours, in residual disease and in metastasis, and their long-term prognostic implications., Methods: This is a population-based cohort study of patients treated with neoadjuvant chemotherapy for breast cancer during 2007-2020 in the Stockholm-Gotland region which comprises 25% of the entire Swedish population. Information was extracted from the National Breast Cancer Registry and electronic patient charts to minimize data missingness and misclassification., Results: In total, 2494 patients received neoadjuvant chemotherapy, of which 2309 had available pretreatment HER2 status. Discordance rates were 29.9% between primary and residual disease (kappa = 0.534), 31.2% between primary tumour and metastasis (kappa = 0.512) and 33.3% between residual disease to metastasis (kappa = 0.483). Adjusted survival curves differed between primary HER2 0 and HER2-low disease (p < 0.001), with the former exhibiting an early peak in risk for death which eventually declined below the risk of HER2-low. Across all disease settings, increasing the number of biopsies increased the likelihood of detecting HER2-low status., Conclusion: HER2 status changes during neoadjuvant chemotherapy and metastatic progression, and the long-term behaviours of HER2 0 and HER2-low disease differ, underscoring the need for obtaining tissue biopsies and for extended follow-up in breast cancer studies., (© 2024. The Author(s).)

Background: The aim of this population-based cohort study was to investigate the impact of neoadjuvant chemotherapy (NACT) compared to adjuvant chemotherapy in prognosis among patients with HR+/HER2 negative breast cancer., Method: This population-based study utilized data from the research database BCBaSe 3.0, based on the Swedish National Quality breast cancer register, including all patients with breast cancer diagnosis in Sweden between 2008 and 2019. Propensity score matching approach was applied. The outcomes of interest consisted of distant-disease free (DDFS), breast-cancer specific (BCSS), and overall survival (OS)., Results: In total, 14 459 patients were included in the study cohort of whom 2086 received NACT. After 1:1 propensity score matching (PSM), 1539 patients in each study group were available for analyses. No statistically significant difference in survival outcomes were observed between patients treated with NACT compared to those treated with adjuvant chemotherapy (Hazard Ratio (HR) for DDFS: 1.20; 95 % CI: 0.80-1.79; HR for BCSS: 1.16; 95 % CI: 0.54-2.49; HR for OS: 1.14; 95 % CI: 0.64-2.05)., Conclusion: In this population-based cohort study of patients with HR+/HER2-breast cancer, the use of NACT seems to be comparable to adjuvant chemotherapy in terms of prognosis, although non-inferiority cannot be proven by this study design. Until further evidence suggesting a survival benefit in favor of either treatment is available, NACT can be pursued when surgical-de-escalation is intended., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Thymidine kinase 1 (TK1) plays a pivotal role in DNA synthesis and cellular proliferation. TK1 has been studied as a prognostic marker and as an early indicator of treatment response in human epidermal growth factor 2 (HER2)-negative early and metastatic breast cancer (BC). However, the prognostic and predictive value of serial TK1 activity in HER2-positive BC remains unknown., Methods: In the PREDIX HER2 trial, 197 HER2-positive BC patients were randomized to neoadjuvant trastuzumab, pertuzumab, and docetaxel (DPH) or trastuzumab emtansine (T-DM1), followed by surgery and adjuvant epirubicin and cyclophosphamide. Serum samples were prospectively collected from all participants at multiple timepoints: at baseline, after cycle 1, 2, 4, and 6, at end of adjuvant therapy, annually for a total period of 5 years and/or at the time of recurrence. The associations of sTK1 activity with baseline characteristics, pathologic complete response (pCR), event-free survival (EFS), and disease-free survival (DFS) were evaluated., Results: No association was detected between baseline sTK1 levels and all the baseline clinicopathologic characteristics. An increase of TK1 activity from baseline to cycle 2 was seen in all cases. sTK1 level at baseline, after 2 and 4 cycles was not associated with pCR status. After a median follow-up of 58 months, 23 patients had EFS events. There was no significant effect between baseline or cycle 2 sTK1 activity and time to event. A non-significant trend was noted among patents with residual disease (non-pCR) and high sTK1 activity at the end of treatment visit, indicating a potentially worse long-term prognosis., Conclusion: sTK1 activity increased following neoadjuvant therapy for HER2-positive BC but was not associated with patient outcomes or treatment benefit. However, the post-surgery prognostic value in patients that have not attained pCR warrants further investigation., Trial Registration: ClinicalTrials.gov, NCT02568839. Registered on 6 October 2015., (© 2024. The Author(s).)

Background: Longitudinal, real-world data on the management of metastatic breast cancer is increasingly relevant to understand breast cancer care in routine clinical practice. Yet such data are scarce, particularly beyond second- and third-line treatment strategies. This study, therefore, examined both the long-term treatment patterns and overall survival (OS) in a regional Swedish cohort of female patients with metastatic breast cancer stratified by subtype in routine clinical practice during a recent eight-year period and correlation to current treatment guidelines., Methods: Consecutive female patients with metastatic breast cancer  clinically managed at Uppsala University Hospital, Uppsala, Sweden, during 2009-2016 and followed until the end of September, 2017 (n = 370) were included and, where possible, classified as having one of five, intrinsic subtypes: Luminal A; Luminal B; human epidermal growth factor receptor 2-positive (HER2+)/ estrogen receptor-positive (ER+); HER2+/estrogen receptor-negative (ER-); or triple negative breast cancer (TNBC). Treatment patterns and OS were estimated by subtype using time-to-event methods., Results: A total of 352/370 patients with metastatic breast cancer (mean age 67.6 years) could be subtyped: 118 (34%) were Luminal A, 119 (34%) Luminal B, 31 (8%) HER2+/ER-, 38 (11%) HER2+/Luminal, and 46 (13%) TNBC. The median number of metastatic treatment lines was 3. Most patients were on active treatment during follow-up (80% of the observation period), except for patients with TNBC who were on treatment for 60% of the observation time. Overall, 67% of patients died whilst on treatment. Among all patients (n = 370), median OS was 32.5 months (95% CI = 28.2-35.7). The 5-year survival rate was highest for HER2+/Luminal (46%) patients, followed by Luminal B (29%), Luminal A (28%), HER2+/ER- (21%), and TNBC (7%). Increasing age and number of metastatic sites also predicted worse survival., Conclusions: Metastatic breast cancer patients in Sweden, irrespective of subtype, generally receive active treatment until time of death. Survival varies considerably across subtypes and is also associated with patient characteristics. Regardless of differences in treatment patterns for Luminal A and B patients, long-term OS was the same., (© 2022. The Author(s).)

Purpose: To examine the influence of type of oncological treatment on sick leave in women of working age with early-stage breast cancer., Methods: We identified 8870 women aged 30-64 diagnosed with stage I-II breast cancer between 2005 and 2012 in the Breast Cancer Data Base Sweden. Associations between type of oncological treatment (radiotherapy, endocrine therapy, and chemotherapy) and sick leave were estimated by hazard ratios, probabilities, and length of sick leave using multi-state survival analysis., Results: During the first 5 years after diagnosis, women aged 50-54 years at diagnosis receiving chemotherapy spent on average 182 (95% CI 151-218) additional days on sick leave compared with women not receiving chemotherapy, but with otherwise similar characteristics. Correspondingly, women initiating endocrine therapy spent 30 (95% CI 18-44) additional days on sick leave and women receiving post-mastectomy radiotherapy 53 (95% CI 37-69) additional days. At year five, the rate of sick leave was increased in women who had received chemotherapy (HR 1.19, 95% CI 1.11-1.28) or endocrine therapy (HR 1.15, 95% CI 1.05-1.26). Chemotherapy and endocrine therapy were associated with increased rates of sick leave due to depression or anxiety., Conclusion: Our findings of increased long-term risks of sick leave after oncological treatment for breast cancer warrant attention from caregivers taking part in cancer rehabilitation. In light of the ongoing debate about overtreatment of early-stage breast cancer, our findings point to the importance of properly selecting patients for chemotherapy not only for the medical toxicity but also the possible impact on their livelihood.

Statins, commonly used to treat hypercholesterolemia, have also been proposed as anti-cancer agents. The identification of a predictive marker is essential. The 3-hydroxy-3-methylglutaryl-coenzyme-A reductase (HMGCR), which is inhibited by statins, might serve as such a marker. Thorough antibody validation was performed for four different HMGCR antibodies. Tumor expression of HMGCR (#AMAb90619, CL0260, Atlas Antibodies, Stockholm, Sweden) was evaluated in the Malmö Diet and Cancer Study breast cancer cohort. Statin use and cause of death data were retrieved from the Swedish Prescribed Drug Register and Swedish Death Registry, respectively. Breast cancer-specific mortality (BCM) according to statin use and HMGCR expression were analyzed using Cox regression models. Three-hundred-twelve of 910 breast cancer patients were prescribed statins; 74 patients before and 238 after their breast cancer diagnosis. HMGCR expression was assessable for 656 patients; 119 showed negative, 354 weak, and 184 moderate/strong expressions. HMGCR moderate/strong expression was associated with prognostically adverse tumor characteristics as higher histological grade, high Ki67, and ER negativity. HMGCR expression was not associated with BCM. Neither was statin use associated with BCM in our study. Among breast cancer patients on statins, no or weak HMGCR expression predicted favorable clinical outcome. These suggested associations need further testing in larger cohorts.

Background: Breast cancer patients with estrogen receptor (ER)-positive disease have a continuous long-term risk for fatal breast cancer, but the biological factors influencing this risk are unknown. We aimed to determine whether high intratumor heterogeneity of ER predicts an increased long-term risk (25 years) of fatal breast cancer., Methods: The STO-3 trial enrolled 1780 postmenopausal lymph node-negative breast cancer patients randomly assigned to receive adjuvant tamoxifen vs not. The fraction of cancer cells for each ER intensity level was scored by breast cancer pathologists, and intratumor heterogeneity of ER was calculated using Rao's quadratic entropy and categorized into high and low heterogeneity using a predefined cutoff at the second tertile (67%). Long-term breast cancer-specific survival analyses by intra-tumor heterogeneity of ER were performed using Kaplan-Meier and multivariable Cox proportional hazard modeling adjusting for patient and tumor characteristics., Results: A statistically significant difference in long-term survival by high vs low intratumor heterogeneity of ER was seen for all ER-positive patients (P < .001) and for patients with luminal A subtype tumors (P = .01). In multivariable analyses, patients with high intratumor heterogeneity of ER had a twofold increased long-term risk as compared with patients with low intratumor heterogeneity (ER-positive: hazard ratio [HR] = 1.98, 95% confidence interval [CI] = 1.31 to 3.00; luminal A subtype tumors: HR = 2.43, 95% CI = 1.18 to 4.99)., Conclusions: Patients with high intratumor heterogeneity of ER had an increased long-term risk of fatal breast cancer. Interestingly, a similar long-term risk increase was seen in patients with luminal A subtype tumors. Our findings suggest that intratumor heterogeneity of ER is an independent long-term prognosticator with potential to change clinical management, especially for patients with luminal A tumors.

Studies of coffee and tea consumption and caffeine intake as risk factors for breast cancer are inconclusive. We assessed coffee and tea consumption, caffeine intake, and possible confounding factors among 42,099 women from the Swedish Women's Lifestyle and Health study, the participants of which were aged 30-49 years at enrollment in 1991-1992. Complete follow-up for breast cancer incidence was performed through 2012 via linkage to national registries. Poisson regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for breast cancer. During follow-up 1,395 breast cancers were diagnosed. The RR was 0.97 (95% CI 0.94-0.99) for a 1-unit increase in cups of coffee/day, 1.14 (95% CI 1.05-1.24) for a 1-unit increase in cups of tea/day, and 0.97 (95% CI 0.95-1.00) for a 100 mg/day increase in caffeine intake. Although the RR for no consumption (RR = 0.86, 95% CI 0.69-1.08), a group with a relatively small number of women, was not statistically significant, women with higher consumption had a decreased breast cancer risk (3-4 cups/day: RR = 0.87, 95% CI 0.76-1.00; ≥5 cups/day: RR = 0.81, 95% CI 0.70-0.94) compared to women consuming 1-2 cups of coffee/day. Compared to no consumption, women consuming >1 cups tea/day showed an increased breast cancer risk (RR = 1.19, 95% CI 1.00-1.42). Similar patterns of estimates were observed for breast cancer risk overall, during pre- and postmenopausal years, and for ER+ or PR+ breast cancer, but not for ER- and PR- breast cancer. Our findings suggest that coffee consumption and caffeine intake is negatively associated with the risk of overall and ER+/PR- breast cancer, and tea consumption is positively associated with the risk of overall and ER+/PR+ breast cancer., (© 2015 UICC.)

Backgrounds: Eribulin is a non-taxane, microtubule dynamics inhibitor approved for the treatment of patients with metastatic breast cancer (MBC) in Europe in March 2011., Material and Methods: For the purpose of an internal quality control, all patients with MBC treated with eribulin at Karolinska University Hospital were registered in a database. Clinical data were collected retrospectively for patients that were registered by August 2012 and safety and efficacy of eribulin were evaluated. Treatment toxicity including fatigue, neurotoxicity and infection was graded according to CTCAE v4.0. Objective response to treatment was investigated using routinely performed radiological assessments. When only clinical assessments were made, the evaluation of the treating physician was used. Furthermore, the efficacy of eribulin was investigated in different tumor subtypes., Results: Forty-eight patients who received at least one cycle of eribulin were identified. Most patients were heavily pretreated with a median of 3 (range 1-7) previous chemotherapy lines prior to eribulin. Median patient age was 56 years (range 35-74). At the end of the analysis, 23 patients were alive and two were still treated with eribulin. No hypersensitivity reactions and no toxic deaths were seen. Fatigue grade 3-4 was observed in three patients (6.3%). One patient experienced grade 4 neurotoxicity. Grade 3-4 neutropenia was documented in 18.8%, and three patients were treated for a grade 3 infection. Interestingly, three individuals developed Herpes zoster reactivation. One patient responded to treatment with complete remission, while 33.3% had a partial response. 48% of all patients had a clinical benefit (objective response or stable disease for more than six months)., Conclusions: Eribulin administered outside of a clinical trial in patients with advanced breast cancer was safe and well tolerated. A clinical benefit was seen in half of the cases. No statistically significant differences in objective response or survival were observed between histopathological subgroups.

Background: Although Osteopontin has been known as a marker for cancer progression, the elevated production of this cytokine is not specific for cancer. We have identified the splice variant Osteopontin-c as being absent from healthy tissue but associated with about 75% of breast cancer cases. However, in previous studies of Osteopontin-c, follow-up information was not available., Methods: Here we have analysed 671 patients, comprising a cohort of 291 paraffin blocks plus a population-based case-control study of 380 arrayed breast tumor tissues., Results: We find that high staining intensity of nuclear Osteopontin-c is strongly associated with mortality in patients with early breast cancer. Cytosolic staining for exon 4, reflective of Osteopontin-a and -b also predicts poor outcome. By contrast, total Osteopontin does not correlate with prognosis. These diverse assessments of Osteopontin also do not correlate with each other, suggesting distinct expression patterns for the variant forms. Consistent with its role in tumor progression, not tumor initiation, Osteopontin-c is not correlated with proliferation markers (Ki-67, cyclin A, cyclin B, cyclin E and cyclin D), neither is it correlated with ER, PR or HER2., Conclusions: The addition of Osteopontin-c immunohistochemistry to standard pathology work-ups may have prognostic benefit in early breast cancer diagnosis.

Background: Emerging data indicate an important role for biopsies of clinically/radiologically defined breast cancer 'recurrences'. The present study investigates tumour related events (relapses, other malignancies, benign conditions) after a primary breast cancer diagnosis., Patients and Methods: The cohort includes 2102 women, representing all patients, with primary invasive breast cancer during 2000-2011 in the county of Värmland, Sweden. A comparative analysis of oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and proliferation (Ki67) between the primary tumour and the relapse was performed and related to outcome., Results: With a mean follow-up time of 4.8 years, 1060 out of 2102 patients have had a biopsy taken after the initial breast cancer diagnosis demonstrating 177 recurrences, 93 other malignancies (colorectal, lung, skin), 40 cancer in situ (skin, breast) and 857 benign lesions. Approximately 70% (177 out of 245) of all cases of relapsed breast cancer underwent a biopsy during this time period. For patients with recurrences, ER (n=127), PR (n=101), HER2 (n=73) and Ki67 (n=55) status in both primary tumour and the corresponding relapse were determined. The discordance of receptor status was 14.2%, 39.6%, 9.6% and 36.3%, respectively. Loss of ER or PR in the relapse resulted in a significant increased risk of death (hazard ratio (HR) 3.62; 95% confidence interval (CI), 1.65-7.94) and (HR 2.34; 95% CI, 1.01-5.47) compared with patients with stable ER or PR positive tumours. The proportion of patients losing ER was bigger in the group treated with endocrine therapy alone or in combination with chemotherapy, 16.7% and 13.3%, respectively, compared with the group treated with chemotherapy alone or that which received no treatment 4.3% and 7.7%, respectively., Conclusion: Discordance of biomarkers between the primary tumour and the corresponding relapse was seen in 10-40% of the patients, adjuvant therapies seem to drive clonal selections. Patients with tumours losing ER or PR during progression have worse survival compared with patients with retained receptor expression., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The purpose of this study is to determine the prognostic role of Ki67 evaluated in relapse biopsies from patients with metastatic breast cancer (MBC). Two hundred and ten patients diagnosed with MBC in Stockholm, Sweden between 1998 and 2009 and with Ki67 assessed at time of first systemic relapse (mKi67) were retrospectively identified and divided into two groups according to mKi67 fraction (low ≤20 %, high >20 %). Post-relapse survival was compared between the groups using Kaplan-Meier and Cox regression methods. Death rate as function of continuous mKi67 was also evaluated. Furthermore, the prognostic role of intra-individual change in Ki67 between primary tumor and matched metastasis was explored by Kaplan-Meier plots. One hundred and twenty-five patients had low and 85 had high mKi67. Median survival was 25 and 17 months in low- and high-mKi67 group, respectively [hazard ratio (HR) 0.69, 95 % confidence intervals (CI) 0.51-0.92, P = 0.01]. In a multivariate model adjusted for prognostic confounders, low-mKi67 showed a non-significant trend toward better survival (HR 0.85, 95 %CI 0.62-1.16, P = 0.30). Nevertheless, mKi67 independently correlated with survival when compared with primary tumor proliferation (HR 0.56, 95 %CI 0.38-0.81, P = 0.002). The 2-year death rate steeply increased as mKi67 increased. Moreover, the change from high in primary tumor to low in metastasis significantly correlated with longer survival when compared with stable Ki67 levels (HR 0.48, 95 %CI 0.31-0.76, P = 0.002). In this cohort of MBC patients, mKi67 inversely but not independently correlated with survival. However, a significant association between mKi67 and survival was shown regardless of primary tumor proliferation.

Purpose: Risk factors for breast cancer vary according to breast cancer subtype. This study analyzes the impact of potential risk factors in breast cancer by androgen receptor (AR) status., Methods: A total of 17,035 women were followed in the population-based prospective Malmö Diet and Cancer Study. Baseline data included lifestyle factors including anthropometry, reproductive history, and exogenous hormone use. During follow-up (mean: 12.8 years), 747 invasive breast cancers were diagnosed. Expression of AR was determined by immunohistochemistry in tumor tissue microarrays., Results: AR status was assessable in 516 of 747 tumors (69%). Among these, 467 tumors (90.5%) were AR positive (AR(+)) and 49 tumors (9.5%) were AR negative (AR(-)). AR negativity was significantly associated with estrogen receptor (ER) and progesterone receptor negativity, higher grade and proliferation (Ki67). Cox regression analyses stratified by AR status showed significant associations between reproductive factors and AR(-) breast cancer. The older the woman at first childbirth the higher the risk of AR(-) breast cancer; adjusted HR≤20yrs = 0.35, HR>20-≤25yrs = 0.62, HRnulliparous = 1.00, HR>25-≤30yrs = 1.29, HR>30yrs = 1.92, p trend = 0.001. No such association was seen for AR(+) tumors. Similarly, ever oral contraceptive use increased the risk of AR(-) breast cancer [Adj. HR = 2.59, 95% CI (1.26-5.34)] compared to never use, but not for AR(+) breast cancer., Conclusions: Advanced age at first child birth and use of oral contraceptives were associated with increased risk of AR(-) breast cancer. This study may contribute to enhanced understanding of the role of the AR in breast carcinogenesis and improve risk stratification tools for personalized breast cancer prevention.

Placental weight may be regarded as an indirect marker of hormone exposures during pregnancy. There is epidemiological evidence that breast cancer mortality in premenopausal women increases with placental weight in the most recent pregnancy. We investigated if this association differs by tumor characteristics, including expression of estrogen and progesterone receptors. In a Swedish population-based cohort, we followed 1,067 women with premenopausal breast cancer diagnosed from 1992 to 2006. Using Cox regression models, we estimated hazard ratios for the association between placental weight and risk of premenopausal breast cancer mortality. In stratified analyses, we estimated mortality risks in subjects with different tumor stages, estrogen receptor (ER) or progesterone receptor (PR) status. Compared with women with placental weight less than 600 g, women with a placental weight between 600 and 699 g were at a 50 % increased risk of mortality, however, not significant change in risk was observed for women with placental weight ≥ 700 g. Mortality risks associated with higher placental weight were more pronounced among ER(-) and PR(-) breast cancer tumors, where both a placental weight 600-699 g and ≥ 700 g were associated with a more than doubled mortality risks compared with tumors among women with placental weight less than 600 g. Moreover, stratified analyses for joint receptor status revealed that a consistent increased mortality risk by placental weight was only apparent in women with ER(-)/PR(-) breast cancer. The increased mortality risk in premenopausal breast cancer associated with higher placental weight was most pronounced among ER(-) and PR(-) tumors.

The emergence of automated image analysis algorithms has aided the enumeration, quantification, and immunohistochemical analyses of tumor cells in both whole section and tissue microarray samples. To date, the focus of such algorithms in the breast cancer setting has been on traditional markers in the common invasive ductal carcinoma subtype. Here, we aimed to optimize and validate an automated analysis of the cell cycle regulator cyclin D1 in a large collection of invasive lobular carcinoma and relate its expression to clinicopathologic data. The image analysis algorithm was trained to optimally match manual scoring of cyclin D1 protein expression in a subset of invasive lobular carcinoma tissue microarray cores. The algorithm was capable of distinguishing cyclin D1-positive cells and illustrated high correlation with traditional manual scoring (κ=0.63). It was then applied to our entire cohort of 483 patients, with subsequent statistical comparisons to clinical data. We found no correlation between cyclin D1 expression and tumor size, grade, and lymph node status. However, overexpression of the protein was associated with reduced recurrence-free survival (P=.029), as was positive nodal status (P<.001) in patients with invasive lobular carcinoma. Finally, high cyclin D1 expression was associated with increased hazard ratio in multivariate analysis (hazard ratio, 1.75; 95% confidence interval, 1.05-2.89). In conclusion, we describe an image analysis algorithm capable of reliably analyzing cyclin D1 staining in invasive lobular carcinoma and have linked overexpression of the protein to increased recurrence risk. Our findings support the use of cyclin D1 as a clinically informative biomarker for invasive lobular breast cancer., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Folate may influence breast cancer development and progression through its role in one-carbon metabolism. However, epidemiologic data on the relation between folate and breast cancer survival are limited. We investigated whether dietary folate intake was associated with survival in 3,116 women diagnosed with breast cancer in the population-based Swedish Mammography Cohort. Participants completed a 67-item food frequency questionnaire in 1987. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for death from breast cancer and death from any cause. During 25,716 person-years of follow-up from 1987 to 2008, there were 852 deaths with 381 breast cancer deaths. Dietary folate intake was inversely associated with breast cancer and overall mortality. Women in the highest quartile of folate intake had a multivariable HR (95% CI) of death from breast cancer of 0.78 (0.58-1.03) compared to those in the lowest quartile (P (trend) = 0.03). The corresponding HR (95% CI) for death from any cause was 0.79 (0.66-0.96; P (trend) = 0.004). The protective association between dietary folate intake and breast cancer death was strongest among those with ER-negative tumors (HR = 0.42; 95% = CI 0.22-0.79; P (trend) = 0.01) comparing the highest to lowest quartile. Our findings suggest that folate intake before breast cancer diagnosis may improve breast cancer and overall survival. While these findings need to be confirmed in future studies, they do offer assurance that dietary folate intake at the levels observed in our population does not unfavorably affect survival after breast cancer.

Treatment of metastatic breast cancer (MBC) has evolved during the last decades but it is largely unknown whether this has led to improved survival in the general MBC population. Based on the regional, population-based breast cancer registry, we identified 5,463 patients diagnosed with MBC in Stockholm County during 1979-2004. Patients were divided into five cohorts based on the year of first MBC diagnosis and observed and relative survival were compared across the cohorts after adjustment for potential confounders. A significant trend of better survival over time was demonstrated for patients 60 years or younger (P < 0.001, by log-rank test for trend), but not for older patients (P = 0.12) or for the whole MBC population (P = 0.13). The adjusted observed survival of patients ≤ 60 years was significantly improved in the 2000-2004 cohort (P < 0.001, hazard ratio = 0.7, 95% confidence interval = 0.58-0.84), corresponding to a clinically significant increase of median survival with more than 3 months and absolute increase of 5-year survival with 8% or more compared to previous periods. Similarly, relative survival analysis indicated a 31% decreased mortality for the younger subpopulation in the 2000-2004 cohort (P < 0.001). Systemic adjuvant treatment was a negative prognostic factor after distant recurrence. Treatment advancements in MBC are not reflected by better survival for the whole MBC population. An improvement is only observed after the year 2000 and is restricted to younger patients.

Background: Epidemiological evidence indicates that individuals with type 2 diabetes are at an increased risk of cancer. Elevated glucose levels, below the diagnostic threshold for diabetes, have also been suggested to be associated with increased cancer risks., Methods: We investigated possible associations between glucose levels and the risk of breast, endometrial, and ovarian cancer in a cohort of more than 230,000 women, for which information on outcome and potential confounders was obtained by record linkage to population-based registers., Results: Diabetes was associated with an increased risk of postmenopausal breast cancer (HR = 1.22, 95% CI 1.04-1.43). An indication of a slightly elevated breast cancer risk was also found in postmenopausal women with impaired glucose metabolism (HR = 1.11, 95% CI 0.96-1.28). Diabetes (HR = 1.46, 95% CI 1.09-1.96) and impaired glucose metabolism (HR = 1.41, 95% CI 1.08-1.85) were associated with an increased risk of endometrial cancer. No associations were found between glucose levels and ovarian cancer risk. Following adjustment for BMI, estimates were attenuated for endometrial cancer, while point estimates for breast and ovarian cancer remained essentially unchanged., Conclusions: Our results indicate that glucose levels below the diagnostic threshold for diabetes modify the risk not only of endometrial cancer but possibly also of postmenopausal breast cancer.

Background: The aim of the present study was to compare both estrogen (ER) and progesterone receptor (PgR) content in operable breast cancers from Vietnamese and Swedish patients., Material and Methods: Primary breast cancer tissues were randomly selected from 249 Vietnamese patients treated in Hanoi, Vietnam between 2002 and 2004 and 1 257 Swedish patients treated in Stockholm, Sweden between 2002 and 2003. Clinical information was available for all patients in the study. The hormone receptor content in tumors from Vietnam was analyzed by immunohistochemistry using an automated slide stainer (Bench MarkXT, Ventana) in combination with anti-ER (SP1 250), and anti-PgR (clone 1E2) rabbit monoclonal antibody. Tumors with ≥ 10% stained nuclei were considered as receptor positive. Tumors from Swedish patients were analyzed with an enzyme immunoassay with a cut-off point of ≥ 0.10 fmol/μg DNA as positive. The hormone receptor frequencies between populations were compared according to clincopathology features., Results: The ER positive rate was higher in premenopausal and lower in postmenopausal Vietnamese patients as compared to Swedish patients with similar menopausal status (71% versus 58%, OR 1.75, p = 0.007; 44% versus 72%, OR 0.32, p < 0.001, respectively). PgR positive tumors were found in 58% and 25% of pre- and postmenopausal Vietnamese patients, respectively. The corresponding figures for Swedish patients were 73% and 66%, respectively., Conclusions: There were significant differences in the frequency of ER/PgR positivity between Vietnam and Swedish breast cancer patients. These differences were independent on menopausal status and age of patients at diagnosis can not be explained by these factors and they can be contributed to knowledge about both basic biology features and prognoses.

Introduction: Given the role of estrogen in breast carcinogenesis and the modification of estrogen receptor (ER) activity by its biochemical cofactors, we hypothesize that genetic variation within ER cofactor genes alters cellular response to estrogen exposure and consequently modifies the risk for ER-positive breast cancer., Methods: We genotyped 790 tagging SNPs within 60 ER cofactor genes in 1,257 cases and 1,464 controls from Sweden and in 2,215 cases and 1,265 controls from Finland, and tested their associations with either ER-positive or ER-negative breast cancer., Results: Seven SNPs showed consistent association with ER-positive breast cancer in the two independent samples, and six of them were located within PPARGC1B, encoding an ER co-activator, with the strongest association at rs741581 (odds ratio = 1.41, P = 4.84 × 10⁻⁵) that survived Bonferroni correction for multiple testing in the combined ER-positive breast cancer sample (Pcorrected = 0.03). Moreover, we also observed significant synergistic interaction (Pinteraction = 0.008) between the genetic polymorphisms within PPARGC1B and ESR1 in ER-positive breast cancer. By contrast, no consistent association was observed in ER-negative breast cancer. Furthermore, we found that administration of estrogen in the MCF-7 cell line induced PPARGC1B expression and enhanced occupancies of ER and RNA polymerase II within the region of SNP association, suggesting the upregulation of PPARGC1B expression by ESR1 activation., Conclusions: Our study revealed that DNA polymorphisms of PPARGC1B, coding a bona fide ER co-activator, are associated with ER-positive breast cancer risk. The feed-forward transcriptional regulatory loop between PPARGC1B and ESR1 further augments their protein interaction, which provides a plausible mechanistic explanation for the synergistic genetic interaction between PPARGC1B and ESR1 in ER-positive breast cancer. Our study also highlights that biochemically and genomically informed candidate gene studies can enhance the discovery of interactive disease susceptibility genes.

We examined associations between food intakes and incident breast cancer, defined by estrogen receptor (ER) and progesterone receptor (PR) status in the Malmö Diet and Cancer cohort (∼17,000 women aged 45-73 yr). The hazard ratios (HRs) of ER+PR+ (n = 270), ER+PR- (n = 87), and ER-PR- (n = 61) tumors and all cancer (n = 544) were estimated after 10 yr of follow-up. In multivariate analysis of ER+PR+ tumors, a protective linear risk trend, indicating change between adjoining food categories, was seen with yogurt (HR = 0.89, 95% CI = 0.80-0.99), but increased risks with eggs (HR = 1.10, 95% CI = 1.01-1.20) and dried soups/sauces (HR = 1.10, 95% CI = 1.00-1.22). In ER-PR- tumors, vegetable-oil-based margarine (HR = 1.31, 95% CI = 1.09-1.59) and dried soups/sauces (HR = 1.31 95% CI = 1.05-1.64) showed increased risks. Heterogeneity was observed between ER+PR+ and ER-PR- tumors for vegetable-oil-based margarine (P < 0.01). Regular milk showed decreased, and dried soups/sauces increased, risk with all breast cancer. The study suggests that fat-containing food may contribute both to hormonal and nonhormonal mechanisms in breast tumor development and supports observations of positive associations between characteristics of Westernized diets and postmenopausal breast cancer.

A large proportion of women with lymph node negative breast cancer do not benefit from chemotherapy. Proliferation markers have been shown to recognize patients at high risk for recurrence. The Ki67 protein has recently been included in the St Gallen guidelines. The authors investigated the prognostic importance of cyclin B1 in node negative breast cancer and included a study of reproducibility. In a population-based case-control study, 190 women who died from breast cancer were defined as cases and 190 women alive at the time for the corresponding case's death were defined as controls. Inclusion criteria were tumor size

Tissue factor (TF)-mediated protease-activated receptor (PAR)-2 signaling is associated with a promigratory, invasive and proangiogenic phenotype in experimental models of breast cancer and has been mechanistically coupled to phosphorylation of the TF cytoplasmic domain (pTF). However, the clinical relevance of these findings is unknown. Here, we provide the first in vivo evidence of TF phosphorylation in experimental as well as clinical breast cancer tumors. pTF was demonstrated in MDA-MB-231 xenografts and in tumors from the MMTV-PyMT transgene model of spontaneous murine breast adenocarcinoma. Tumors from PAR-2-deficient transgenic mice were negative for pTF, thus linking pTF to PAR-2 signaling. The clinical correlation between TF, pTF, PAR-1, PAR-2 and vascular endothelial growth factor (VEGF)-A was determined by immunohistochemistry on tumors from a cohort of 172 consecutive primary breast cancer patients, with a median follow-up time of 50 months. In 160 evaluable patient tumors, pTF was associated with TF (p = 0.01) and cancer cell expression of PAR-1 (p = 0.001), PAR-2 (p = 0.014) and VEGF-A (p = 0.003) using chi(2) test. PAR-2 and VEGF-A were coexpressed (p = 0.013) and associated with a more aggressive phenotype. Interestingly, all patients experiencing recurrences had tumors expressing pTF and PAR-2, and pTF alone as well as coexpression of pTF and PAR-2 were significantly correlated with shorter recurrence-free survival (log rank test, p = 0.04 and p = 0.02, respectively). This study provides the first evidence to link PAR-2 expression and TF phosphorylation to clinical data in human breast cancer. In conjunction with experimental tumor models, these data support an important role of TF-PAR-2 signaling in breast cancer recurrence.

Introduction: The HOXB13:IL17BR index has been identified to predict clinical outcome in the setting of adjuvant tamoxifen monotherapy of breast cancer. Further studies have shown that HOXB13 in particular can indicate benefit of prolonged tamoxifen treatment. Patients with high-expressing tumors did not benefit from prolonged treatment, suggesting that HOXB13 might be involved in tamoxifen resistance. No studies have been made regarding the HOXB13 protein levels in breast cancer. The aim of our study was to investigate whether tamoxifen benefit can be correlated to different levels of HOXB13 protein expression., Methods: We used immunohistochemistry to analyze protein levels of HOXB13 in tumor samples from 912 postmenopausal node-negative breast cancer patients randomized to adjuvant tamoxifen therapy or no endocrine treatment., Results: Tamoxifen-treated patients with estrogen receptor-positive tumors expressing none or low levels of HOXB13 had a clear benefit from tamoxifen in terms of longer distant recurrence-free survival (DRFS) (hazard ratio = 0.38, 95% confidence interval = 0.23 to 0.60, P = 0.000048). However, for patients with a high or intermediate HOXB13 tumor expression, tamoxifen did not prolong the DRFS compared with the untreated patients (hazard ratio = 0.88, 95% confidence interval = 0.47 to 1.65, P = 0.69). Interaction between HOXB13 expression and benefit from tamoxifen was statistically significant for DRFS (P = 0.035). No prognostic value could be ascribed to HOXB13 among systemically untreated patients., Conclusions: A high HOXB13 expression was associated with decreased benefit from tamoxifen, which indicates that HOXB13 protein level may be used as a predictive marker for tamoxifen treatment.

Background: Coffee and tea consumption has been inconsistently associated with the risk of breast cancer. We examined the associations of caffeinated coffee and black tea consumption with the incidence of breast cancer, overall and by estrogen receptor (ER) and progesterone receptor (PR) status of the tumor, in the Swedish Mammography Cohort., Methods: We prospectively followed up 61,433 women who were cancer free at baseline in 1987-1990. Coffee and tea consumption was assessed with a food-frequency questionnaire administered at baseline and in 1997. Incident invasive breast cancer cases were ascertained by linkage with Swedish Cancer registers., Results: Over a mean follow-up of 17.4 years, through December 2007, there were 2,952 incident cases of invasive breast cancer identified. Coffee consumption was not associated with risk of overall breast cancer (multivariate relative risk (RR) for ≥ 4 cups/day versus <1 cup/day = 1.02; 95% CI, 0.87-1.20) or with any subtype defined by ER and PR status. Black tea consumption was significantly positively associated with risk of overall breast cancer and ER+/PR+ tumors. The multivariate RRs comparing ≥ 2 cups/day of tea with no consumption were 1.22 (95% CI, 1.05-1.42) for overall breast cancer and 1.36 (95% CI, 1.09-1.69) for ER+/PR+ tumors., Conclusion: Findings from this prospective study do not support a role of coffee consumption in the development of breast cancer but suggest that black tea consumption may be positively associated with risk of ER+/PR+ tumors.

Chromosomal instability (CIN) is a major characteristic of many cancers. We investigated whether putatively functional single nucleotide polymorphisms (SNPs) in genes related to CIN (CENPF, ESPL1, NEK2, PTTG1, ZWILCH, ZWINT) affect breast cancer (BC) risk and clinical outcome in a Swedish cohort of 749 incident BC cases with detailed clinical data and up to 15 years of follow-up and 1493 matched controls. As a main observation, carriers of the A allele of the CENPF SNP rs438034 had a worse BC-specific survival compared to the wild type genotype GG carriers (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.19-5.90), although they were less likely to have regional lymph node metastases (odds ratio (OR) 0.71, 95% CI 0.51-1.01) and tumours of stage II-IV (OR 0.73, 95% CI 0.54-0.99). As there is increasing evidence that CENPF is associated with poor prognosis in patients with primary BC, further independent studies are needed to clarify the importance of genetic variation in the CENPF gene in the clinic.

Background: Calcium may potentially influence the risk of breast cancer because of its role in regulating cell proliferation, differentiation, and apoptosis. However, prospective studies of calcium intake in relation to breast cancer incidence are sparse., Objective: The objective of this study was to prospectively examine and show the association, if any, of dietary calcium intake with risk of breast cancer by estrogen receptor (ER) and progesterone receptor (PR) status of the tumor., Design: The Swedish Mammography Cohort is a population-based prospective cohort of 61,433 women who were cancer-free at enrollment in 1987-1990. Dietary calcium intake was assessed with a food-frequency questionnaire at baseline and again in 1997. Cox proportional hazards models were used to estimate rate ratios (RRs) and 95% CIs, adjusted for breast cancer risk factors., Results: During an average of 17.4 y of follow-up, 2,952 incident cases of invasive breast cancer were ascertained. Dietary calcium intake was not associated with risk of overall breast cancer; the multivariate RR for the highest compared with the lowest quintile of calcium intake was 0.97 (95% CI: 0.87, 1.09; P for trend: 0.49). There was a statistically significant inverse trend for ER-negative/PR-negative (ER-/PR-) breast cancer (P for trend: 0.02); the multivariate RR for the comparison of extreme quintiles of calcium intake was 0.66 (95% CI: 0.44, 0.99). Calcium intake was not associated with ER-positive/PR-positive (ER+/PR+) or ER+/PR- tumors., Conclusions: Our findings do not support an association between dietary calcium intake and overall breast cancer risk. The inverse relation between calcium intake and ER-/PR- breast cancer requires confirmation in other studies.

Background: Differences in the estrogen receptor (ER) status of tumors may explain ambiguities in epidemiologic studies between the blood concentrations of enterolactone and breast cancer. To our knowledge, the association between enterolactone and ERbeta-defined breast cancer has previously not been examined., Methods: A nested case-control study within the Malmö Diet and Cancer cohort used 366 cases and 733 matched controls to identify the major determinants of plasma enterolactone and to examine the association between enterolactone concentration and breast cancer risk and if this association differs depending on the ERalpha and ERbeta status of tumors. A modified diet history method assessed dietary habits. Time-resolved fluoroimmunoassay determined enterolactone concentrations and immunohistochemistry using tissue microarray determined ER status., Results: Dietary fiber, as well as fruits and berries, and high-fiber bread showed statistically significant correlations with enterolactone (r, 0.13-0.22). Smoking and obesity were associated with lower enterolactone concentrations. Enterolactone concentrations above the median (16 nmol/L) were associated with reduced breast cancer risk when compared with those below [odds ratio, 0.75; 95% confidence interval (95% CI), 0.58-0.98]. The reduced risk was only observed for ERalpha [positive (+); odds ratio, 0.73; 95% CI, 0.55-0.97] and ERbeta [negative (-)] tumors (odds ratio, 0.60; 95% CI, 0.42-0.84), with significantly different risks for ERbeta (-) and ERbeta (+) tumors (P for heterogeneity = 0.04)., Conclusions: This study supports the suggestion that enterolactone is a biomarker of a healthy lifestyle. The protective association between enterolactone and breast cancer was significantly different between ERbeta (-) and ERbeta (+) tumors and most evident in tumors that express ERalpha but not ERbeta.

We investigate the prognostic significance of the pro-angiogenic cytokine vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor 1 (PAI-1), and S-phase fraction (SPF) for distant disease free survival (DDFS) in 219 premenopausal patients with node-negative breast cancer (NNBC). In univariate analysis significantly shorter DDFS was observed for patients with high VEGF (p=0.006), high uPA (p=0.001), and high SPF (p<0.001). The prognostic significance of VEGF varied over time being very strong for early relapses (0-2.25 years follow-up) (HR=7.9; p=0.006) while no difference was seen in the subsequent follow-up period (HR=1.3; p=0.62). In a series of bivariate analyses VEGF provided prognostic information during the whole observation period (0-72 months) in addition to age, tumour size, oestrogen receptor (ER), progesterone receptor (PgR), and uPA. Also this effect was more pronounced during the first follow-up period suggesting VEGF as a marker of early recurrences.

CYP1A2 plays a key role in the metabolism of both estrogen and coffee. Women with higher coffee intake and the CYP1A2*1F A/A genotype have a ratio of high 2-hydroxyestrone (2-OHE1) to 16alpha-OHE1. 2-OHE1 is a weak estrogen and may even block the estrogen receptor (ER), whereas 16alpha-OHE1 is procarcinogenic. We hypothesized that moderate to high coffee consumption (> or =2 cups per day) combined with the CYP1A2*1F A/A genotype would be associated with a later age at diagnosis and a greater proportion of ER-negative (ER-) tumors among patients with breast cancer. We genotyped 458 patients with breast cancer (age, 25-99 years) in Lund, Sweden, for CYP1A2*1F. Information on lifestyle factors and tumor characteristics were obtained from preoperative questionnaires and pathology reports. Among patients with CYP1A2*1F A/A (51.3%), moderate to high consumption was associated with a later age at diagnosis compared with low coffee consumption (59.8 versus 52.6 years, P = 0.0004). These patients were also more likely to have ER- tumors than patients with low consumption (14.7% versus 0%, P = 0.018). Coffee was not associated with ER status or age at diagnosis in patients with at least one C allele. Age at diagnosis was not associated with ER status in patients with CYP1A2*1F A/A, but younger patients (<50 years) with at least one C allele were more likely to have ER- tumors compared with older patients (odds ratio, 4.2; 95% confidence interval, 1.9-9.3; P = 0.0002). These findings raise the hypothesis that coffee slows the growth of ER-positive tumors in patients with CYP1A2*1F A/A and may have implications for breast cancer if confirmed.

We investigated whether dietary intakes of total fat, monounsaturated fat (MUFA), polyunsaturated fat (PUFA) and saturated fat (SFA) were associated with breast cancer risk in a prospective cohort of 49 261 Swedish women (30-49 years at enrolment), which yielded 974 breast cancer cases by December 2005. Further, we evaluated if associations differed by oestrogen and/or progesterone receptor tumour status. Total fat, MUFA, PUFA or SFA were not associated with risk overall. However, women in the highest MUFA and PUFA quintile intake had a reduced breast cancer risk after age 50 years (hazard ratios: 95% confidence interval=0.45: 0.25-0.99 and 0.54: 0.35-0.85, respectively) compared to women in the lowest quintile. The associations did not differ by oestrogen or progesterone receptor status. Despite the negative findings, type of fat during premenopausal years may have later differential effects on risk.

Background: The role of insulin-like growth factor (IGF)-I in breast cancer remains controversial, despite numerous reports on the association of the hormone with breast cancer or high-risk mammographic densities. We hypothesized that exposure to elevated IGF-I during early pregnancy, a period characterized by intense cell proliferation in the breasts and in the presence of high concentrations of sex steroids, will be associated with increased maternal risk to develop a breast malignancy., Methods: The Northern Sweden Maternity Cohort is an ongoing prospective study, collecting blood samples from first-trimester-pregnant women since 1975 as part of screening for infectious diseases. A case-control study (212 cases and 369 controls) was nested among Northern Sweden Maternity Cohort members who delivered singleton babies. RIA was used to measure IGF-I and IGF-II levels. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI)., Results: Breast cancer risk increased with increasing IGF-I (top tertile OR, 1.7; 95% CI, 1.1-2.7). The association was stronger among the primiparous (OR, 2.2; 95% CI, 1.1-4.4) than in the nonprimiparous women (OR, 1.4; 95% CI, 0.7-2.8). Upper-tertile risks seemed to decrease within the <28-, 28 to 33, and >33-year groups of age at sampling, from 2.5 (0.9-7.6) to 2.1 (0.9-5.0) and 1.2 (0.5-2.5), respectively. There was no association of breast cancer with first-trimester-pregnancy IGF-II., Conclusions: The study offers further evidence that IGF-I is important in breast cancer. Our findings suggest that the adverse effect of IGF-I on the breast may be stronger before the remodeling of the gland induced by a first pregnancy.

The effect of classic breast cancer risk factors on hormone receptor-defined breast cancer is not fully clarified. We explored these associations in a Swedish population-based study. Postmenopausal women ages 50 to 74 years, diagnosed with invasive breast cancer during 1993 to 1995, were compared with 3,065 age frequency-matched controls. We identified 332 estrogen receptor (ER-) and progesterone receptor (PR-) negative, 286 ER+PR-, 71 ER-PR+, 1,165 ER+PR+, and 789 tumors with unknown receptor status. Unconditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (95% CI). Women ages >or=30 years, compared with those ages 20 to 24 years at first birth, were at an increased risk of ER+PR+ tumors (OR, 1.5; 95% CI, 1.2-1.8) but not ER-PR- tumors (OR, 1.1; 95% CI, 0.8-1.6). Women who gained >or=30 kg in weight during adulthood had an approximately 3-fold increased relative risk of ER+PR+ tumors (OR, 2.7; 95% CI, 1.9-3.8), but no risk increase of ER-PR- tumors (OR, 1.0; 95% CI, 0.5-2.1), compared with women who gained <10 kg. Compared with never users, women who used menopausal estrogen-progestin therapy for at least 5 years were at increased risk of ER+PR+ tumors (OR, 3.0; 95% CI, 2.1-4.1) but not ER-PR- tumors (OR, 1.3; 95% CI, 0.7-2.5). In conclusion, other risk factors were similarly related to breast cancer regardless of receptor status, but high age at first birth, substantial weight gain in adult age, and use of menopausal estrogen-progestin therapy were more strongly related to receptor-positive breast cancer than receptor-negative breast cancer.

Although obesity is one of the established risk factors for postmenopausal breast cancer, it is not clear whether this positive association differs across estrogen receptor (ER) and progesterone receptor (PR) status of breast tumors. We evaluated the association between body weight and ER/PR defined breast cancer risk stratified by postmenopausal hormone (PMH) use and a family history of breast cancer in the population-based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Relative body weight was measured by body mass index (kg/m2) based on self-reported weight and height collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratios derived from Cox proportional hazards regression models. During an average of 8.3-year follow-up, 1,188 invasive breast cancer cases with known ER and PR status were diagnosed. When comparing to normal weight group, we observed a positive association between obesity and risk for the development of ER+ PR+ tumors (RR = 1.67, 95% CI = 1.34-2.07) and an inverse association for the development of all PR- tumors (RR = 0.68, 95% CI = 0.47-0.98). Statistically significant heterogeneity was observed in the RRs between ER+ PR+ tumors and all PR- tumors (p(heterogeneity) < 0.0001). The positive association of obesity with the development of ER+ PR+ tumors was confined to never-users of PMHs (RR = 1.90 (CI 95%:1.38-2.61)) and to those without a family history of breast cancer (RR = 1.82 (CI 95%:1.45-2.29)). Our results support the hypothesis that excess endogenous estrogen due to obesity contributes to an increased risk of ER+ PR+ postmenopausal breast cancer., (Copyright 2006 Wiley-Liss, Inc.)

The aim of this study was to investigate possible associations between the expression of c-erbB-2 and the angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), p53 status, routine breast cancer prognostic factors and survival. Expression of c-erbB-2, VEGF, bFGF, and p53 protein was determined with an enzyme-linked immunosorbent assay (ELISA) in 656 patients with primary breast cancer (median follow-up time of 83 months). In 60 cases, we also used immunohistochemistry (IHC) for c-erbB-2 evaluation, to be used as a reference for the ELISA. Overexpression of c-erbB-2 was significantly related to a higher expression of VEGF, lower bFGF content, negative steroid receptor status, and a high S-phase fraction. In multivariate analysis, c-erbB-2 was an independent prognostic factor for relapse-free survival (RFS) and overall survival (OS) in all patients, and in node-positive patients, irrespective of the adjuvant systemic therapy. Combined survival analyses regarding c-erbB-2 and VEGF yielded additional prognostic information.

We studied the relevance of adenomatous polyposis coli (APC)/beta-catenin signalling in the development of breast cancer by analysing the expression of beta-catenin in 54 primary breast tumours (34 ductal and 20 lobular). We showed that 13% of the tumours exhibited upregulated levels of beta-catenin in the cytosol suggesting that defects in APC/beta-catenin signalling components had lowered the rate of beta-catenin degradation. No mutations were observed in the amino-terminal region of beta-catenin, which comprises conserved serine residues important for phosphorylation-dependent degradation of the protein, but the APC protein was altered in 6% of the tumours. Tyrosine phosphorylation of beta-catenin was detected in only one tumour and could, therefore, not have been responsible for the observed increased levels of this protein. Although 9% of the tumours displayed upregulation of c-MYC protein, there was no correlation with beta-catenin overexpression, suggesting that increased beta-catenin expression is not the major cause of c-myc gene activation in breast cancer. It is imperative that elements that selectively drive the oncogenic activity of beta-catenin in breast cancer be identified.

To test the hypothesis that osteoporosis, which results partly from long-term estrogen deficiency, is associated with a lowered risk of breast and endometrial cancer, a population-based cohort study was performed in Sweden. Some 18,000 women were followed through record-linkages after a first hip fracture, on average for almost six years, to ascertain the incidence of breast and endometrial cancer. Expected numbers were derived from the general population. Overall, 253 cases of breast cancer were observed cf 300 expected (standardized incidence ratio [SIR] = 0.84; 95 percent confidence interval [CI] = 0.74-0.95). Forty-eight cases of endometrial cancer were found cf 55 expected (SIR = 0.87, CI = 0.54-1.16). There was no clearcut pattern of breast cancer risk by age at diagnosis of hip fracture, follow-up time, or calendar period. Our results are consistent with the a priori hypothesis that long-term estrogen deficiency is associated with a reduced risk of developing breast cancer as well as endometrial cancer.