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The metastatic potential of estrogen receptor (ER)-positive breast cancers is heterogeneous and distant recurrences occur months to decades after primary diagnosis. We have previously shown that patients with tumors classified as ultralow risk by the 70-gene signature have a minimal long-term risk of fatal breast cancer. Here, we evaluate the previously unexplored underlying clinical and molecular characteristics of ultralow risk tumors in 538 ER-positive patients from the Stockholm tamoxifen randomized trial (STO-3). Out of the 98 ultralow risk tumors, 89% were luminal A molecular subtype, whereas 26% of luminal A tumors were of ultralow risk. Compared to other ER-positive tumors, ultralow risk tumors were significantly (Fisher's test, P

Resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

BackgroundBreast 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.MethodsThe 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.ResultsA 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).ConclusionsPatients 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.

BackgroundBreast cancer molecular prognostic tools that predict recurrence risk have mainly been established on endocrine-treated patients and thus are not optimal for the evaluation of benefit from endocrine therapy. The Stockholm tamoxifen (STO-3) trial which randomized postmenopausal node-negative patients to 2-year tamoxifen (followed by an optional randomization for an additional 3-year tamoxifen vs nil), versus no adjuvant treatment, provides a unique opportunity to evaluate long-term 20-year benefit of endocrine therapy within prognostic risk classes of the 70-gene prognosis signature that was developed on adjuvantly untreated patients.MethodsWe assessed by Kaplan-Meier analysis 20-year breast cancer-specific survival (BCSS) and 10-year distant metastasis-free survival (DMFS) for 538 estrogen receptor (ER)-positive, STO-3 trial patients with retrospectively ascertained 70-gene prognosis classification. Multivariable analysis of long-term (20 years) BCSS by STO-3 trial arm in the 70-gene high-risk and low-risk subgroups was performed using Cox proportional hazard modeling adjusting for classical patient and tumor characteristics.ResultsTamoxifen-treated, 70-gene low- and high-risk patients had 20-year BCSS of 90 and 83%, as compared to 80 and 65% for untreated patients, respectively (log-rank p

Tamoxifen is an established treatment for breast cancer, but its long-term effects on survival and on secondary cancers are not fully evaluated. We studied 30 years outcome of 4124 postmenopausal patients who were randomized to receive (totally) two or five years of adjuvant tamoxifen. After 5 years of follow-up, when tamoxifen treatment was finished in both groups, until 15 years of follow-up, overall mortality (HR 0.80, 95% CI 0.72–0.90, p < 0.001), breast cancer mortality for all patients (HR 0.80, 95% CI 0.68–0.94, p = 0.006) and breast cancer mortality for patients with estrogen receptor positive disease (HR 0.67, 95% CI 0.55–0.83, p < 0.001) were significantly reduced in the five-year group as compared to the two-year group. After 15 years, the difference remained but did not further increase. In the five-year group, the incidence of contralateral breast cancer was gradually reduced during the entire period of observation. The incidence of lung cancer was also reduced in the five-year group. In contrast there was an increased endometrial cancer incidence in the five-year group and for those receiving 40 mg of tamoxifen this incidence was further increased. Three more years of tamoxifen therapy reduced the risk of breast cancer mortality. The difference was established during the first 15 years after randomization. Moreover, the incidence of contralateral breast cancer gradually decreased for 30 years. The incidence of lung cancer was reduced in the five-year group. In contrast the incidence of endometrial cancer was increased. • After 30 years of follow-up, 5 years as compared to 2 years of tamoxifen. • Had reduced breast cancer mortality. • Had reduced all-cause mortality. • Had reduced the incidence of contralateral disease. • Had increased the incidence of endometrial cancer. [ABSTRACT FROM AUTHOR]

Background: Gene expression (GEX) signatures in breast cancer provide prognostic information, but little is known about their predictive value for tamoxifen treatment. We examined the tamoxifen-predictive value and prognostic effects of different GEX signatures in premenopausal women with early breast cancer. Methods: RNA from formalin-fixed paraffin-embedded tumor tissue from premenopausal women randomized between two years of tamoxifen treatment and no systemic treatment was extracted and successfully subjected to GEX profiling (n = 437, NanoString Breast Cancer 360™ panel). The median follow-up periods for a recurrence-free interval (RFi) and overall survival (OS) were 28 and 33 years, respectively. Associations between GEX signatures and tamoxifen effect were assessed in patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+ /HER2−) tumors using Kaplan–Meier estimates and Cox regression. The prognostic effects of GEX signatures were studied in the entire cohort. False discovery rate adjustments (q-values) were applied to account for multiple hypothesis testing. Results: In patients with ER+/HER2− tumors, FOXA1 expression below the median was associated with an improved effect of tamoxifen after 10 years with regard to RFi (hazard ratio [HR]FOXA1(high) = 1.04, 95% CI = 0.61–1.76, HRFOXA1(low) = 0.30, 95% CI = 0.14–0.67, qinteraction = 0.0013), and a resembling trend was observed for AR (HRAR(high) = 1.15, 95% CI = 0.60–2.20, HRAR(low) = 0.42, 95% CI = 0.24–0.75, qinteraction = 0.87). Similar patterns were observed for OS. Tamoxifen was in the same subgroup most beneficial for RFi in patients with low ESR1 expression (HRRFi ESR1(high) = 0.76, 95% CI = 0.43–1.35, HRRFi, ESR1(low) = 0.56, 95% CI = 0.29–1.06, qinteraction = 0.37). Irrespective of molecular subtype, higher levels of ESR1, Mast cells, and PGR on a continuous scale were correlated with improved 10 years RFi (HRESR1 = 0.80, 95% CI = 0.69–0.92, q = 0.005; HRMast cells = 0.74, 95% CI = 0.65–0.85, q < 0.0001; and HRPGR = 0.78, 95% CI = 0.68–0.89, q = 0.002). For BC proliferation and Hypoxia, higher scores associated with worse outcomes (HRBCproliferation = 1.54, 95% CI = 1.33–1.79, q < 0.0001; HRHypoxia = 1.38, 95% CI = 1.20–1.58, q < 0.0001). The results were similar for OS. Conclusions: Expression of FOXA1 is a promising predictive biomarker for tamoxifen effect in ER+/HER2− premenopausal breast cancer. In addition, each of the signatures BC proliferation, Hypoxia, Mast cells, and the GEX of AR, ESR1, and PGR had prognostic value, also after adjusting for established prognostic factors. Trial registration This trial was retrospectively registered in the ISRCTN database the 6th of December 2019, trial ID: https://clinicaltrials.gov/ct2/show/ISRCTN12474687. [ABSTRACT FROM AUTHOR]

Over the last few decades, improved and more individualized treatment has contributed to the increased survival rate of patients with breast cancer. However, certain patients may receive excessive treatment resulting in undesired side effects. In a previous study, it was demonstrated that systemically untreated patients with estrogen receptor (ER)-positive/progesterone receptor (PR)-negative tumors with high Ras-related protein Rab-6C (RAB6C) expression levels (RAB6C+) had prolonged distant recurrence-free survival compared with that of patients exhibiting low RAB6C (RAB6C-)-expressing tumors. The aim of the present study was to investigate whether RAB6C predicts the effectiveness of tamoxifen treatment. The present study used a dataset comprising 486 female patients with ER+ tumors from a randomized study conducted by the Stockholm Breast Cancer Study Group between November 1976 and August 1990. The patients were considered as low-risk if their tumor size was ≤30 mm and their lymph node status was negative. Patients were followed up until distant recurrence, mortality or when 25 years after randomization was achieved, whichever occurred first. For patients with ER+/PR-/RAB6C+ tumors, prolonged distant recurrence-free survival could not be observed if the patients were treated with tamoxifen [hazard ratio (HR), 1.82; 95% confidence interval (CI), 0.69-4.79; P=0.23], whereas patients with ER+/PR-/RAB6C- tumors had 75% reduced distant recurrence risk (HR, 0.25; 95% CI, 0.09-0.70; P=0.008). In the ER+/PR+ subgroup, patients with RAB6C- and RAB6C+ tumors benefited from tamoxifen treatment, though it was most evident in the RAB6C+ group (HR, 0.27; 95% CI, 0.13-0.58; P=0.001). The results of the present study indicated that, for patients with ER+/PR- tumors, those with low RAB6C expression benefited from tamoxifen treatment, whereas no benefit was observed in patients with high RAB6C levels. [ABSTRACT FROM AUTHOR]

The majority of breast cancer tumors are estrogen receptor-positive (ER+) and can be treated with endocrine therapy. However, certain patients may exhibit a good prognosis without systemic treatment. The aim of the present study was to identify novel prognostic factors for patients with ER+ breast cancer tumors using gene copy data, and to investigate if these factors have prognostic value in subgroups categorized by progesterone receptor status (PR). Public data, including the whole genome gene copy data of 199 systemically untreated patients with ER+ tumors, were utilized in the present study. To assess prognostic value, patients were divided into two groups using the median gene copy number as a cut-off for the SNPs that were the most variable. One SNP was identified, which indicated that the Ras-related protein Rab-6C (RAB6C) gene may exhibit prognostic significance. Therefore, RAB6C protein expression was subsequently investigated in a second independent cohort, consisting of 469 systematically untreated patients (of which 310 were ER+) who received long term follow-up. In the public data set, a distant recurrence risk reduction of 55% was determined for copy numbers above the median value of RAB6C compared with numbers below [multivariable adjusted hazard ratio (HR), 0.45; 95% CI 0.28–0.72; P=0.001)]. It was also more pronounced in the ER+/PR− subgroup (HR, 0.15; 95% CI, 0.05–0.46; P=0.001). In the second cohort, patients of the ER+/PR− subgroup who exhibited high RAB6C expression had a reduced distant recurrence risk (HR, 0.17; 95% CI, 0.05–0.60; P=0.006). However, this was not identified among ER+/PR+ tumors (HR, 1.31; 95% CI, 0.69–2.48; P=0.41). The results of the present study indicated that RAB6C serves as an independent prognostic factor of distant recurrence risk in systemically untreated patients with an ER+/PR− tumor. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Breast cancer molecular prognostic tools that predict recurrence risk have mainly been established on endocrine-treated patients and thus are not optimal for the evaluation of benefit from endocrine therapy. The Stockholm tamoxifen (STO-3) trial which randomized postmenopausal node-negative patients to 2-year tamoxifen (followed by an optional randomization for an additional 3-year tamoxifen vs nil), versus no adjuvant treatment, provides a unique opportunity to evaluate long-term 20-year benefit of endocrine therapy within prognostic risk classes of the 70-gene prognosis signature that was developed on adjuvantly untreated patients. Methods: We assessed by Kaplan-Meier analysis 20-year breast cancer-specific survival (BCSS) and 10-year distant metastasis-free survival (DMFS) for 538 estrogen receptor (ER)-positive, STO-3 trial patients with retrospectively ascertained 70-gene prognosis classification. Multivariable analysis of long-term (20 years) BCSS by STO-3 trial arm in the 70-gene high-risk and low-risk subgroups was performed using Cox proportional hazard modeling adjusting for classical patient and tumor characteristics. Results: Tamoxifen-treated, 70-gene low- and high-risk patients had 20-year BCSS of 90 and 83%, as compared to 80 and 65% for untreated patients, respectively (log-rank p < 0.0001). Notably, there is equivalent tamoxifen benefit in both high (HR 0.42 (0.21-0.86), p = 0.018) and low (HR 0.46 (0.25-0.85), p = 0.013) 70-gene risk categories even after adjusting for clinico-pathological factors for BCSS. Limited tamoxifen exposure as given in the STO-3 trial provides persistent benefit for 10-15 years after diagnosis in a time-varying analysis. 10-year DMFS was 93 and 85% for low- and high-risk tamoxifen-treated, versus 83 and 70% for low- and high-risk untreated patients, respectively (log-rank p < 0.0001). Conclusions: Patients with ER-positive breast cancer, regardless of high or low 70-gene risk classification, receive significant survival benefit lasting over 10 years from adjuvant tamoxifen therapy, even when given for a relatively short duration. [ABSTRACT FROM AUTHOR]

Introduction: 17β-hydroxysteroid dehydrogenases (17βHSDs) are important enzymes regulating the pool of bioactive steroids in the breast. The current study was undertaken in order to evaluate implications of 17βHSD14 in breast cancer, measuring 17βHSD14 protein expression in breast tumours. Methods: An antibody targeting the 17βHSD14 antigen was generated and validated using HSD17B14-transfected cells and a peptide-neutralising assay. Tissue microarrays with tumours from 912 post-menopausal women diagnosed with lymph node-negative breast cancer, and randomised to adjuvant tamoxifen or no endocrine treatment, were analysed for 17βHSD14 protein expression with immunohistochemistry. Results: Results were obtained from 847 tumours. Patients with oestrogen positive tumours with high 17βHSD14 expression had fewer local recurrences when treated with tamoxifen (HR 0.38; 95% C.I. 0.19-0.77, p = 0.007) compared to patients with lower tumoural 17βHSD14 expression, for whom tamoxifen did not reduce the number of local recurrences (HR 1.19; 95% C.I. 0.54-2.59; p = 0.66). No prognostic importance of 17βHSD14 was seen for systemically untreated patients. Conclusions: Using a highly specific validated antibody for immunohistochemical analysis of a large number of breast tumours, we have shown that tumoural expression levels of 17βHSD14 can predict the outcome of adjuvant tamoxifen treatment in terms of local recurrence-free survival in patients with lymph node-negative ER+ breast cancer. The results need be verified to confirm any clinical relevance. [ABSTRACT FROM AUTHOR]

Background: Obesity has been shown to be an indicator of poor prognosis for patients with primary breast cancer (BC) regardless of the use of adjuvant systemic therapy. Patients and methods: This is a retrospective analysis of 2,887 node-positive BC patients enrolled in the BIG 02-98 adjuvant study, a randomised phase III trial whose primary objective was to evaluate disease-free survival (DFS) by adding docetaxel to doxorubicin-based chemotherapy. In the current analysis, the effect of body mass index (BMI) on DFS and overall survival (OS) was assessed. BMI was obtained before the first cycle of chemotherapy. Obesity was defined as a BMI ≥ 30 kg/m². Results: In total, 547 (19%) patients were obese at baseline, while 2,340 (81%) patients were non-obese. Estimated 5-year OS was 87.5% for non-obese and 82.9% for obese patients (HR 1.34; P = 0.013). Estimated 5-years DFS was 75.9% for non-obese and 70.0% for obese patients (HR 1.20; P = 0.041). In a multivariate model, obesity remained an independent prognostic factor for OS and DFS. Conclusions: In this study, obesity was associated with poorer outcome in node-positive BC patients. Given the increasing prevalence of obesity worldwide, more research on improving the treatment of obese BC patients is needed. [ABSTRACT FROM AUTHOR]

Background: Docetaxel is more effective than doxorubicin for patients with advanced breast cancer. The Breast International Group 02-98 randomized trial tested the effect of incorporating docetaxel into anthracycline-based adjuvant chemotherapy and compared sequential vs concurrent administration of doxorubicin and docetaxel. Methods: Patients with lymph node-positive breast cancer (n = 2887) were randomly assigned to one of four treatments: 1) sequential control (four cycles of doxorubicin at 75 mg/m2, followed by three cycles of cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]); 2) concurrent control (four cycles of doxorubicin at 60 mg/m2 plus cyclophosphamide at 600 mg/m2, followed by three cycles of CMF); 3) sequential docetaxel (three cycles of doxorubicin at 75 mg/m2, followed by three cycles of docetaxel at 100 mg/m2, followed by three cycles of CMF); 4) concurrent docetaxel (four cycles of doxorubicin at 50 mg/m2 plus docetaxel at 75 mg/m2, followed by three cycles of CMF). The primary comparison evaluated the efficacy of including docetaxel regardless of schedule and was planned after 1215 disease-free survival (DFS) events (ie, relapse, second primary cancer, or death from any cause). Docetaxel and control treatment groups were compared by log-rank tests, and hazard ratios (HR) of DFS events were calculated by Cox modeling. All statistical tests were two-sided. Results: Due to a lower-than-anticipated rate of relapse, this analysis was performed after 5 years with 732 events. Patients in control arms had a 5-year DFS of 73% (95% confidence interval [Cl] = 70% to 75%). Docetaxel treatment resulted in an improvement in DFS of borderline statistical significance compared with control treatment (HR = 0.86, 95% Cl = 0.74 to 1.00; P = .05). However, DFS in the sequential docetaxel arm was better than that in the concurrent docetaxel arm (HR = 0.83, 95% Cl = 0.69 to 1.00) and in the sequential control arm (HR = 0.79, 95% Cl = 0.64 to 0.98). Conclusions: Incorporating docetaxel into anthracycline-based therapy resulted in an improvement in DFS that was of borderline statistical significance. However, important differences may be related to doxorubicin and docetaxel scheduling, with sequential but not concurrent administration, appearing to produce better DFS than anthracycline-based chemotherapy. [ABSTRACT FROM AUTHOR]

p53 protein accumulation and gene mutation have been implicated in resistance to cytotoxic treatment. This study was performed to further assess the predictive value of p53 in breast cancer. Postmenopausal patients were randomized to adjuvant chemotherapy with cyclophosphamide, metothrexate, or 5-fluorouracil (CMF) vs. postoperative radiotherapy. The patients were also randomized to adjuvant tamoxifen vs. no endocrine treatment. Immunohistochemistry (IHC) and single-strand conformation polymorphism (SSCP), followed by direct sequencing, was performed. The p53 altered group, regarded as positive for p53 gene mutation and=or p53 protein accumulation, tended to benefit more from CMF than from radiotherapy as compared with others regarding distant recurrences. In the group lacking p53 alteration there was a significantly decreased local recurrence rate in the radiotherapy group as compared with the CMF group (RR = 0.24, 95% CI = 0.083–0.62), whereas no benefit from radiotherapy was found for patients showing p53 alterations. Tamoxifen significantly decreased the rate of distant recurrence for estrogen receptor-positive patients with no apparent difference in relation to p53 alteration. It is suggested that p53 alteration indicates benefit from CMF compared with radiotherapy regarding distant recurrence-free survival and the best local control with radiotherapy is achieved in the absence of p53 alteration. Finally. altered p53 status is probably not a marker of resistance to tamoxifen. [ABSTRACT FROM AUTHOR]

A Swedish cooperative trial demonstrated that 5 years of adjuvant tamoxifen was more beneficial than 2 years of tamoxifen in the treatment of postmenopausal women with estrogen receptor (ER) positive, early stage, invasive breast cancer. The main aim of the present study was to investigate the importance of progesterone receptor (PgR) and ER concentration levels for patients participating in the trial and still distant recurrence free two years after the primary operation. Subgroup analyses revealed that only patients with ER positive and PgR positive breast cancer had improved distant recurrence free survival (DRFS) by prolonged tamoxifen therapy ( p=0.0016). Patients with ER negative and PgR negative as well as ER positive and PgR negative tumors showed no significant effect of prolonged tamoxifen ( p=0.53 and p=0.80, respectively). The percentage of ER negative and PgR positive breast cancers was too small (2.2%) for any meaningful subgroup analysis. There was a significant positive trend that the concentration level of PgR (high positive vs. low positive vs. negative) decreased the recurrence rate for those with prolonged therapy. No corresponding pattern was found for the ER content. S-phase fraction did not correlate to the recurrence rate of PgR positive breast cancers. Patients recurring during tamoxifen therapy had receptor negative tumors to a greater extent than those recurring after tamoxifen treatment. In conclusion, prolonged tamoxifen therapy for 5 years instead of 2 years was found to be beneficial for patients with ER positive and PgR positive breast cancer, whereas three extra years of tamoxifen had little or no effect for patients with ER positive but PgR negative tumors as well as for steroid receptor negative patients. [ABSTRACT FROM AUTHOR]

The inositol hexakisphosphate kinase (IP6K) 1 and 2 genes are localized at 3p21.31, a highly altered gene-dense chromosomal region in cancer. The IP6Ks convert IP6 to IP7, which inhibits activation of the tumor-promoting PI3K/Akt/mTOR signaling pathway. IP6K2 has been suggested to be involved in p53-induced apoptosis, while IP6K1 may stimulate tumor growth and migration. The present study aimed to elucidate the role of the two IP6Ks in predicting outcome in patients with breast cancer. To the best of our knowledge, the role of IP6K was analyzed for the first time in tumors from three cohorts of patients with breast cancer; one Swedish low-risk cohort, one Dutch cohort and the TCGA dataset. Analyses of gene -and protein expression and subcellular localization were included. IP6K2 gene expression was associated with ER positivity and nuclear p-Akt. Improved prognosis was detected with high IP6K2 gene expression compared with low IP6K2 gene expression in systemically untreated patients in the Swedish low-risk and Dutch cohorts. In the TCGA dataset, IP6K2 prognostic value was significant when selecting for tumors with wild-type TP53. A multivariable analysis testing IP6K2 against other cancer-related genes at 3p.21.31, including IP6K1 and clinical biomarkers, revealed that IP6K2 was associated with decreased risk of distant recurrence. IP6K1 was associated with increased risk of distant recurrence in the multivariable test and protein analysis revealed trends of worse prognosis with high IP6K1 in the cytoplasm. The expression levels of IP6K1 and IP6K2 were associated to a high extent; however, a diverging prognostic value of the two genes was observed in breast cancer. The present data suggest that IP6K2 can be a favorable prognostic factor, while IP6K1 may not be. [ABSTRACT FROM AUTHOR]

From January 1, 1983, through December 31, 1992, a total of 4610 patients entered a randomized trial that compared mortality among patients receiving 2 years of adjuvant tamoxifen therapy with that in patients receiving 5 years of adjuvant tamoxifen therapy, 4175 of whom were recurrence free after 2 years of tamoxifen therapy. Among the 2046 patients randomly assigned to the 5-year group all-cause mortality, breast cancer-specific mortality, and the incidence of contralateral breast cancer were reduced, compared with those among 2129 patients randomized in the 2-year group, but the incidence of endometrial cancer was increased. In addition, mortality from coronary heart disease was statistically significantly reduced in the 5-year group, compared with that in the 2-year group (hazard ratio = 0.67, 95% confidence interval = 0.47 to 0.94; P = .022 [two-sided Wald test]). Ten years after surgery, 2.1% of the patients in the 5-year group and 3.5% of those in the 2-year group had died from coronary heart disease. No statistically significant increases in mortality from other heart diseases, cerebrovascular diseases, or other vascular diseases were observed. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the expression and predictive role of the Mre11/Rad50/Nbs1 (MRN) complex and the ataxia-telangiectasia mutated protein (ATM) for the outcome of radiotherapy in breast cancer patients.Methods and Materials: The protein expression of ATM and the DNA repair proteins in the MRN complex were investigated using immunohistochemistry in tumors from 224 women with early breast cancer, who were randomized to receive postoperative radiotherapy or adjuvant chemotherapy.Results: Compared with normal breast tissue, the staining intensity of Mre11, Rad50, Nbs1, and ATM was reduced in a majority of the tumors. Weak expression of the MRN complex was correlated with high histologic grade and estrogen receptor negativity (p = 0.01 and p = 0.0001, respectively). Radiotherapy significantly reduced the risk of local recurrence as compared with chemotherapy (p = 0.04). The greatest benefit of radiotherapy was seen in patients with moderate/strong expression of the MRN complex (relative risk = 0.27, 95% confidence interval = 0.098-0.72, p = 0.009), whereas patients with negative/weak MRN expression had no benefit of radiotherapy compared with adjuvant chemotherapy. These results suggest that an intact MRN complex is important for the tumor cell eradicating effect of radiotherapy.Conclusions: Reduced expression of the MRN complex predicts a poor effect of radiotherapy in patients with early breast cancer. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the impact of postmastectomy radiation therapy (PMRT) for patients with T1-T2 tumors and 1 to 3 positive lymph nodes enrolled on the Breast International Group (BIG) 02-98 trial.Methods and Materials: The BIG 02-98 trial randomized patients to receive adjuvant anthracycline with or without taxane chemotherapy. Delivery of PMRT was nonrandomized and performed according to institutional preferences. The present analysis was performed on participants with T1-T2 breast cancer and 1 to 3 positive lymph nodes who had undergone mastectomy and axillary nodal dissection. The primary objective of the present study was to examine the effect of PMRT on risk of locoregional recurrence (LRR), breast cancer-specific survival, and overall survival.Results: We identified 684 patients who met the inclusion criteria and were included in the analysis, of whom 337 (49%) had received PMRT. At 10 years, LRR risk was 2.5% in the PMRT group and 6.5% in the no-PMRT group (hazard ratio 0.29, 95% confidence interval 0.12-0.73; P = .005). Lower LRR after PMRT was noted for patients randomized to receive adjuvant chemotherapy with no taxane (10-year LRR: 3.4% vs 9.1%; P = .02). No significant differences in breast cancer-specific survival (84.3% vs 83.9%) or overall survival (81.7% vs 78.3%) were observed according to receipt of PMRT.Conclusion: Our analysis of the BIG 02-98 trial shows excellent outcomes in women with T1-T2 tumors and 1 to 3 positive lymph nodes found in axillary dissection. Although PMRT improved LRR in this cohort, the number of events remained low at 10 years. In all groups, 10-year rates of LRR were relatively low compared with historical studies. As such, the use of PMRT in women with 1 to 3 positive nodes should be tailored to individual patient risks. [ABSTRACT FROM AUTHOR]

Aim Breast International Group (BIG) 2–98 is a randomised phase III trial that tested the effect of adding docetaxel, either in sequence to or in combination with anthracycline-based adjuvant chemotherapy, in women with node-positive breast cancer (BC). Here, we present the 10-year final trial safety and efficacy analyses. We also report an exploratory analysis on the predictive value of Ki67 for docetaxel efficacy, in the BIG 2–98 and using a pooled analysis of three other randomised trials. Patients and methods 2887 patients were randomly assigned in a 2 × 2 trial design to one of four treatments. The primary objective was to evaluate the overall efficacy of docetaxel on disease free survival (DFS). Secondary objectives included comparisons of sequential docetaxel versus sequential control arm, safety and overall survival (OS). Ki67 expression was centrally evaluated by immunohistochemistry. Results After a median follow-up of 10.1 years, the addition of docetaxel did not significantly improve DFS or OS (hazard ratio (HR) = 0.91, 95% confidence interval (CI) = 0.81–1.04; P = 0.16 and HR = 0.88, 95% CI = 0.76–1.03; P = 0.11, respectively). Sequential docetaxel did not improve DFS compared to the sequential control arm (HR = 0.86, 95% CI = 0.72–1.03; P = 0.10). In oestrogen receptor (ER)-positive tumours with Ki67 ⩾ 14%, the addition of docetaxel resulted in 5.4% improvement in 10-year OS ( P = 0.03, test for interaction = 0.1). In a multivariate model, there was a trend for improved DFS and OS in ER-positive patients with high Ki67 and treated with docetaxel (HR = 0.79, 95% CI = 0.63–1.01; P = 0.05 and HR = 0.76, 95% CI = 0.57–1.01; P = 0.06, respectively). A pooled analysis of four randomised trials showed a benefit of taxanes in highly proliferative ER-positive disease but not in low proliferating tumours (interaction test P = 0.01). Conclusion The DFS benefit previously demonstrated with sequential docetaxel is no longer observed at 10 years. However, an exploratory analysis suggested a benefit of docetaxel in patients with highly proliferative ER-positive BC. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Akt is a signalling modulator for many cellular processes, including metabolism, cell proliferation, cell survival and cell growth. Three isoforms of Akt have been identified, but only a few studies have concerned the isoform-specific roles in the prognosis of breast cancer patients. The aim of this study was to investigate the prognostic value of v-akt murine thymoma viral oncogene homologue 1 (Akt1) and v-akt murine thymoma viral oncogene homologue 2 (Akt2) in oestrogen receptor positive (ER+) and oestrogen receptor negative (ER–) breast cancer with long-term follow-up. Material and methods: The expression of Akt in tumour tissue was analysed with immunohistochemistry in a cohort of 272 postmenopausal patients with stage II breast cancer. The median follow-up time was 19years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox’s proportional hazards model. Results: The risk of distant recurrence was reduced for patients with ER+ tumours expressing Akt2 compared to patients with no Akt2 expression (HR=0.49, 95% CI 0.29–0.82, p =0.007). When adjusting for important clinical tumour characteristics and treatment, Akt2 was still an independent prognostic factor (HR=0.38, 95% CI 0.21–0.68, p =0.001) and the association remained long-term. The prognostic value of Akt2 increased with higher oestrogen receptor levels from no effect among patients with ER– tumours to 68% risk reduction for the group with high ER-levels (P for trend=0.042). Akt1 showed no significant prognostic information. Conclusion: Our results indicate that Akt2 expression is associated with a lower distant recurrence rate for patients with ER+ tumours and that this association remains long-term. The prognostic value of Akt2 increases with higher oestrogen receptor expression, motivating further mechanistic studies on the role of Akt2 in ER+ breast cancer. [Copyright &y& Elsevier]

17ß-Hydroxysteroid dehydrogenases (17HSDs) are involved in the local regulation of sex steroids. 17HSD1 converts oestrone (E1) to the more potent oestradiol (E2) and 17HSD2 catalyses the reverse reaction. The aim of this study was to investigate the expression of these enzymes in premenopausal breast cancers and to analyse if they have any prognostic or tamoxifen predictive value. Premenopausal patients with invasive breast cancer, stage II (UICC), were randomised to either 2years of adjuvant tamoxifen (n =276) or no tamoxifen (n =288). The median follow-up was 13.9years (range 10.5–17.5). The expression of 17HSD1 and 17HSD2 was analysed with immunohistochemistry using tissue microarrays. The enzyme expression level (–/+/++/+++) was successfully determined in 396 and 373 tumours, respectively. Women with hormone-receptor positive tumours, with low levels (–/+/++) of 17HSD1, had a 43% reduced risk of recurrence, when treated with tamoxifen (Hazard Ratio (HR)=0.57; 95% confidence interval (CI), 0.37–0.86; p =0.0086). On the other hand high expression (+++) of 17HSD1 was associated with no significant difference between the two treatment arms (HR=0.91; 95% CI, 0.43–1.95; p =0.82). The interaction between 17HSD1 and tamoxifen was significant during the first 5 years of follow-up (p =0.023). In the cohort of systemically untreated patients no prognostic importance was observed for 17HSD1. We found no predictive or prognostic value for 17HSD2. This is the first report of 17HSD1 in a cohort of premenopausal women with breast cancer randomised to tamoxifen. Our data suggest that 17HSD1 might be a predictive factor in this group of patients. [Copyright &y& Elsevier]

Abstract: Background: Adjuvant treatment with tamoxifen reduces the risk of contralateral breast cancer in hormone-responsive postmenopausal patients, whereas the effect in premenopausal women has not been fully elucidated. We have therefore studied the effect of tamoxifen on contralateral breast cancer in premenopausal women in a controlled randomised trial. Patients and methods: Premenopausal women (564) with stage II breast cancers were randomised to 2 years of tamoxifen versus control irrespective of oestrogen receptor (ER) and progesterone receptor (PgR) status. The median follow-up for patients not developing a contralateral cancer was 14 years. Results: In the control group 35 women, and in the tamoxifen group 17 women, developed a contralateral breast cancer as a primary event. Tamoxifen significantly reduced the risk of contralateral breast cancer in all women regardless of age (hazard ratio (HR) 0.5, p =0.02). In subgroup analysis the risk reduction was most pronounced in patients <40 years of age (HR 0.09, p =0.02). A risk reduction was also seen in women 40–49 years of age or ⩾50 years of age, although in these subgroups this did not reach statistical significance. The reduced risk of contralateral breast cancer was persistent during the whole follow-up time. Conclusion: In this randomised trial, adjuvant treatment using tamoxifen for 2 years reduced the incidence of contralateral breast cancer by 50% in all premenopausal women, and by 90% in women <40 years of age. The effect of tamoxifen was not significantly dependent on time. [Copyright &y& Elsevier]

Adjuvant therapy of breast cancer patients reduces the risk of recurrence and mortality, although, a substantial proportion of patients acquire resistance and relapse in the disease. Predictors of therapeutic response are therefore important to avoid both therapy resistance and the side effects of inefficient regimes. The p53 protein is a key determinant to induce either growth arrest or apoptosis in response to cytotoxic stress.In the search for predictive markers of cancer therapy we investigated a common Arg72/Pro72 polymorphism in the p53 gene, which has been shown to influence the apoptotic potential. Using PCR and RFLP we genotyped 220 breast cancer patients randomized to radiotherapy versus chemotherapy and tamoxifen versus no tamoxifen.Oestrogen-receptor positive patients possessing at least one Pro72 allele had better distant recurrence-free survival when randomized to tamoxifen compared to those who were not (P=0.0033), as also demonstrated by the significantly decreased hazard ratio (HR=0.28, 95% CI 0.12-0.65). Among patients homozygous for the Arg72 genotype the outcome was approximately equal between tamoxifen treated and non-tamoxifen treated patients (P=0.65). When the calculated hazard ratios for the genotypes were compared by an interaction test a significant difference was found (P=0.0088).The present report indicates that the codon 72 polymorphism in the p53 gene may be a predictor of tamoxifen response, suggesting that breast cancer patients lacking the Pro72 allele might be candidates for other therapies. [ABSTRACT FROM AUTHOR]

Abstract: Adjuvant tamoxifen treatment increases recurrence-free survival (RFS) and overall survival (OS) in early breast cancer, although in premenopausal patients the number of studies comparing tamoxifen vs no treatment are limited. We report herein the effect on RFS of adjuvant tamoxifen treatment in a multicentre trial of premenopausal patients with stage II breast cancer patients randomised between 1986 and 1991 to 2 years of tamoxifen treatment (n=276) or no treatment (n=288). The receptor status of the tumour was known for 541 (96%) of the patients included. Tamoxifen treatment significantly increased RFS in patients with hormone receptor-positive (oestrogen receptor-positive (ER+) and/or progesterone receptor-positive (PR+)) tumours (Relative Risk (RR) 0.65; 95% Confidence Interval (CI): 0.48–0.89, P=0.006), and the beneficial effect of tamoxifen was extended to patients with indicators of poor prognosis, such as young age and nodal-positivity. PR status was a significant predictor of response to tamoxifen in multivariate models with testing of interactions of hormone receptor status and adjuvant therapy. [Copyright &y& Elsevier]