Immunohistochemical profiles of brain metastases from breast cancer

Single-center study on clinicopathological and typical molecular pathologic features of metastatic brain tumor

BACKGROUND

The metastatic brain tumor is the most common brain tumor. The aim of this study was to demonstrate the clinicopathological and molecular pathologic features of brain metastases (BM).

METHODS

A total of 269 patients were diagnosed with BM through surgical resection at Seoul St. Mary's Hospital from January 2010 to March 2020. We reviewed the clinicopathological features and molecular status of primary and metastatic brain tissues using immunohistochemistry and molecular pathology results.

RESULTS

Among 269 patients, 139 males and 130 females were included. The median age of primary tumor was 58 years (range, 13 to 87 years) and 86 patients (32.0%) had BM at initial presentation. Median BM free interval was 28.0 months (range, 1 to 286 months). The most frequent primary site was lung 46.5% (125/269), and followed by breast 15.6% (42/269), colorectum 10.0% (27/269). Epidermal growth factor receptor (EGFR) mutation was found in 50.8% (32/63) and 58.0% (40/69) of lung primary and BM, respectively. In both breast primary and breast cancer with BM, luminal B was the most frequent subtype at 37.9% (11/29) and 42.9% (18/42), respectively, followed by human epidermal growth factor receptor 2 with 31.0% (9/29) and 33.3% (14/42). Triple-negative was 20.7% (6/29) and 16.7% (7/42), and luminal A was 10.3% (3/29) and 7.1% (3/42) of breast primary and BM, respectively. In colorectal primary and colorectal cancer with BM, KRAS mutation was found in 76.9% (10/13) and 66.7% (2/3), respectively.

CONCLUSIONS

We report the clinicopathological and molecular pathologic features of BM that can provide useful information for understanding the pathogenesis of metastasis and for clinical trials based on the tumor's molecular pathology.

Molecular aspects of brain metastases in breast cancer

Brain metastases (BM) are a common and devastating manifestation of breast cancer (BC). BM are particularly frequent in the HER2-positive and triple-negative breast cancer phenotypes and usually occur following the metastatic spread to extracranial sites. Several genes mediating BM and biomarkers predicting their risk in BC have been reported in the past decade. These findings have advanced the understanding of BM pathobiology and paved the way for developing new therapeutic strategies but they still warrant a thorough clinical validation. Hence, a better understanding of the mechanistic aspects of BM and delineating the interactions of tumor cells with the brain microenvironment are of utmost importance. This review discusses the molecular basis of the metastatic cascade: the epithelial-mesenchymal transition, cancer, and tumor microenvironment interaction and intravasation, priming of the metastatic niche in the brain, and survival in the new site. We also outline the postulated mechanisms of BC cells' brain tropism. Finally, we discuss advances in the field of biomarkers (both tissue-based and liquid-based) that predict BM from BC.

Receptor discordance among primary tumors, brain metastases and extra-brain metastases in patients with breast cancer

Background: To investigate the expression status of estrogen receptor (ER), progesterone receptor (PR) and HER2 in patients with breast cancer brain metastases (BM). Methods: Patients who underwent craniotomy for BM were included. The status of ER, PR and HER2 (including HER2-low expression) in primary breast tumors (PT), BM and extra-BM (EM) was determined. Results: Between PT and BM, conversion of hormone receptor and HER2 occurred in 28% (30/107) and 12% (10/86) of cases. When considering three-tiered categorization of HER2, the conversion rate reached 31%. In the paired EM and BM (n = 39), the discordance rates were 18%, 3% and 22%, respectively. Conclusion: Receptor discordance was dynamic and relevant, especially using new HER2 categorization.

Conversion of ER, PR, HER2 and Ki-67 and Prognosis in breast cancer metastases to the brain

Objective

This study aimed to analyze the expression levels of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 proliferation index in the brain metastatic lesions and primary lesions in Chinese patients with breast cancer brain metastasis (BCBM) and determine the correlation between their changes and patients' survival.

Methods

A retrospective analysis was performed on patients with BCBM. The clinical characteristic of these patients was collected. The differences in the expression levels of the ER, PR, HER-2, and Ki-67 index between the primary lesions and brain lesions were evaluated, and the association between the differences and survival was analyzed.

Results

The conversion rate of anyone receptor (ER, PR, or HER2) between the primary lesions and brain metastatic lesions was 45.0% (18/40), of which the ER inconsistency rate was 25.0%, the PR inconsistency rate was 22.5%, and the HER-2 inconsistency rate was 15.0%, and the receptor conversion resulted in a subtype conversion of 27.5% (11/40). The patients with HER-2 expression discordance between the primary lesions and the brain metastatic lesions had significantly longer survival times (58.9 vs. 26.4 months, P = 0.04) after diagnosis of brain metastases.

Conclusion

In this study, 45.0% of breast cancer patients developed biomarker-conversion between the primary lesions and brain metastatic lesions, and the differences in the expression levels of the ER, PR, and HER-2, the change in Ki-67 index between the primary lesions and brain lesions may predict patients' survival.

Estrogen/progesterone receptor and HER2 discordance between primary tumor and brain metastases in breast cancer and its effect on treatment and survival

BACKGROUND

Breast cancer treatment is based on estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth factor receptor 2 (HER2). At the time of metastasis, receptor status can be discordant from that at initial diagnosis. The purpose of this study was to determine the incidence of discordance and its effect on survival and subsequent treatment in patients with breast cancer brain metastases (BCBM).

METHODS

A retrospective database of 316 patients who underwent craniotomy for BCBM between 2006 and 2017 was created. Discordance was considered present if the ER, PR, or HER2 status differed between the primary tumor and the BCBM.

RESULTS

The overall receptor discordance rate was 132/316 (42%), and the subtype discordance rate was 100/316 (32%). Hormone receptors (HR, either ER or PR) were gained in 40/160 (25%) patients with HR-negative primary tumors. HER2 was gained in 22/173 (13%) patients with HER2-negative primary tumors. Subsequent treatment was not adjusted for most patients who gained receptors-nonetheless, median survival (MS) improved but did not reach statistical significance (HR, 17-28 mo, P = 0.12; HER2, 15-19 mo, P = 0.39). MS for patients who lost receptors was worse (HR, 27-18 mo, P = 0.02; HER2, 30-18 mo, P = 0.08).

CONCLUSIONS

Receptor discordance between primary tumor and BCBM is common, adversely affects survival if receptors are lost, and represents a missed opportunity for use of effective treatments if receptors are gained. Receptor analysis of BCBM is indicated when clinically appropriate. Treatment should be adjusted accordingly.

KEY POINTS

1. Receptor discordance alters subtype in 32% of BCBM patients.2. The frequency of receptor gain for HR and HER2 was 25% and 13%, respectively.3. If receptors are lost, survival suffers. If receptors are gained, consider targeted treatment.

Subtype switching in breast cancer brain metastases: a multicenter analysis

Background

Breast cancer (BC) brain metastases (BM) can have discordant hormonal or human epidermal growth factor receptor 2 (HER2) expression compared with corresponding primary tumors. This study aimed to describe incidence, predictors, and survival outcomes of discordant receptors and associated subtype switching in BM.

Methods

BCBM patients seen at 4 tertiary institutions who had undergone BM resection or biopsy were included. Surgical pathology reports were retrospectively assessed to determine discordance between the primary tumor and the BCBM. In discordant cases, expression in extracranial metastases was also assessed.

Results

In BM from 219 patients, prevalence of any discordance was 36.3%; receptor-specific discordance was 16.7% for estrogen, 25.2% for progesterone, and 10.4% for HER2. Because estrogen and progesterone were considered together for hormonal status, 50 (22.8%) patients switched subtype as a result; 20 of these switches were HER2 based. Baseline subtype predicted switching, which occurred in up to 37.5% of primary HR+ patients. Moreover, 14.8% of initially HER2-negative patients gained HER2 in the BM. Most (63.6%) discordant patients with extracranial metastases also had discordance between BM and extracranial subtype. Loss of receptor expression was generally associated with worse survival, which appeared to be driven by estrogen loss (hazard ratio = 1.80, P = 0.03). Patients gaining HER2 status (n = 8) showed a nonsignificant tendency toward improved survival (hazard ratio = 0.64, P = 0.17).

Conclusions

In this multicenter study, we report incidence and predictors of subtype switching, the risk of which varies considerably by baseline subtype. Switches can have clinical implications for prognosis and treatment choice.

Breast Cancer Brain Metastasis-Overview of Disease State, Treatment Options and Future Perspectives

Simple Summary

In this review, we present the latest information on the pathophysiology, diagnosis, and local and systemic treatment of brain metastases from breast cancer, with a focus on recent publications. Improving the local treatment and subtype-specific systemic therapies through advancements in basic and translational research will contribute to better clinical outcomes for patients with breast cancer brain metastasis.

Abstract

Breast cancer is the second most common origin of brain metastasis after lung cancer. Brain metastasis in breast cancer is commonly found in patients with advanced course disease and has a poor prognosis because the blood–brain barrier is thought to be a major obstacle to the delivery of many drugs in the central nervous system. Therefore, local treatments including surgery, stereotactic radiation therapy, and whole-brain radiation therapy are currently considered the gold standard treatments. Meanwhile, new targeted therapies based on subtype have recently been developed. Some drugs can exceed the blood–brain barrier and enter the central nervous system. New technology for early detection and personalized medicine for metastasis are warranted. In this review, we summarize the historical overview of treatment with a focus on local treatment, the latest drug treatment strategies, and future perspectives using novel therapeutic agents for breast cancer patients with brain metastasis, including ongoing clinical trials.

Systematic review and meta-analysis of breast cancer brain metastasis and primary tumor receptor expression discordance

Background

Change in hormone receptor (estrogen [ER] and progesterone [PR]) and/or human epidermal growth factor receptor type 2 (HER2) status during the evolutionary course of metastatic breast cancer and the effect of tumor classification subtype switching remain understudied and underappreciated in brain metastasis patients.

Methods

Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic review of series published prior to April 2020 obtained from the Medline database of biopsied or resected breast cancer brain metastasis (BCBM) was performed. Weighted random effects models were used to calculate pooled estimates.

Results

15 full-text articles were included with receptor expression analyses on 1373 patients who underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. Primary tumor receptor expression immunophenotypes were 45.0% ER+, 41.0% ER−, 31.0% PR+, 51.0% PR−, 35% HER2+, and 47.0% HER2−. Corresponding BCBM immunophenotypes were 19.0% ER+, 31.0% ER−, 13.0% PR+, 40.0% PR−, 21.0% HER2+, and 26.0% HER2−. On primary/BCBM comparison, 540 patients (42.6%) exhibited discordance in any receptor with 17.0% (95% CI: 13.0%–23.0%) discordant on ER, 23.0% (95% CI: 18.0%–30.0%) discordant on PR, and 12.0% (95% CI: 8.0%–16.0%) discordant on HER2 status. The most common receptor conversions found in BCBM were ER loss 11.0% (95% CI: 8.0%–16.0%), PR loss 15.0% (95% CI: 11.0%–21.0%), and HER2 gain 9.0% (95% CI: 7.0%–11.0%).

Conclusions

BCBM exhibits significant receptor expression discordance in comparison to primary tumors in approximately 40% of patients. Classification patterns need to be analyzed to determine factors predictive of BCBM/primary tumor discordance. Overall, tumor subtype switching and its effect on clinical management remains underappreciated.

Discordance of immunohistochemical markers between primary and recurrent or metastatic breast cancer: A retrospective analysis of 107 cases

There is a discordance in the immunohistochemical markers between primary breast cancer and recurrent or metastatic breast cancer. This study aimed to assess the recent trends and prognostic features in the treatment of recurrent or metastatic breast cancerOverall, 107 patients were identified from January 2001 to August 2018 at the Peking Union Medical College Hospital, Beijing, and People's Republic of China to obtain a cohort of breast carcinoma patients who were confirmed to have recurrent or metastatic breast cancer by histopathology. We evaluated patient and tumor characteristics and examined the relationships between these factors and prognosis.The estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) positivity, and Ki67 index in primary breast cancer were 63.6% (68/107), 58.9% (63/107), 19.8% (21/106) and 75.8% (75/99), respectively, while those in recurrent or metastatic lesions were 60.6% (65/107) (P = .672), 46.7% (50/107) (P = 0.013), 23.8% (25/105) (P = 0.482)and 83.5%(81/97)(P = 0.178), respectively. The discordance rate of HER2 expression was 10.6% (11/104), while that of PR expression was 23.3% (21/90). HER2 was the most stable biomarker. The discordance rates for luminal A and HER2 were as high as 100% and 25%, respectively, while the luminal B and triple negative values were as low as 8.3% and 5.3%, respectively.ER and PR positivity and the Ki-67 index tended to increase due to recurrence or metastases; however, the discordance for PR and Ki-67 was high. PR is more variable than ER in the expression of primary and recurrent or metastatic breast cancer. The expression of HER2 receptor was the most stable and the discordance rate of triple negative breast cancer was the lowest. Therefore, although changes in biomarkers are due to recurrence or metastasis, pathological confirmation and exploration of markers are very important.

Challenges in the treatment of breast cancer brain metastases: evidence, unresolved questions, and a practical algorithm

Breast cancer is the leading cause of brain metastases in women. Large randomized clinical trials that have evaluated local therapies in patients with brain metastases include patients with brain metastases from a variety of cancer types. The incidence of brain metastases in the breast cancer population continues to grow, which is, aside from the rising breast cancer incidence, mainly attributable to improvements in systemic therapies leading to more durable control of extracranial metastatic disease and prolonged survival. The management of breast cancer brain metastases remains challenging, even more so with the continued advancement of local and highly effective systemic therapies. For most patients, a metastases-directed initial approach (i.e., radiation, surgery) represents the most appropriate initial therapy. Treatment should be based on multidisciplinary team discussions and a shared decision with the patients taking into account the risks and benefits of each therapeutic modality with the goal of prolonging survival while maintaining quality of life. In this narrative review, a multidisciplinary group of experts will address challenging questions in the context of current scientific literature and propose a therapeutic algorithm for breast cancer patients with brain metastases.

Receptor Conversion in Distant Breast Cancer Metastases: A Systematic Review and Meta-analysis

Background

In metastatic breast cancer, hormone and/or human epidermal growth factor receptor 2 (HER2)-targeted therapy decision-making is still largely based on tissue characteristics of the primary tumor. However, a change of estrogen receptor alpha (ERα), progesterone receptor (PR), and HER2 status in distant metastases has frequently been reported. The actual incidence of this phenomenon has been debated.

Methods

We performed a meta-analysis including 39 studies assessing receptor conversion from primary breast tumors to paired distant breast cancer metastases. We noted the direction of change (positive to negative or vice versa) and performed subgroup analyses for different thresholds for positivity, the type of test used to assess HER2 receptor status, and metastasis location-specific differences (two-sided tests).

Results

Overall, the incidence of receptor conversion varied largely between studies. For ERα, PR, and HER2, we found that random effects pooled positive to negative conversion percentages of 22.5% (95% confidence interval [CI] = 16.4% to 30.0%), 49.4% (95% CI = 40.5% to 58.2%), and 21.3% (95% CI = 14.3% to 30.5%), respectively. Negative to positive conversion percentages were 21.5% (95% CI = 18.1% to 25.5%), 15.9% (95% CI = 11.3% to 22.0%), and 9.5% (95% CI = 7.4% to 12.1%). Furthermore, ERα discordance was statistically significantly higher in the central nervous system and bone compared with liver metastases (20.8%, 95% CI = 15.0% to 28.0%, and 29.3%, 95% CI = 13.0% to 53.5%, vs 14.3%, 95% CI = 11.3% to 18.1, P = .008 and P < .001, respectively), and PR discordance was higher in bone (42.7%, 95% CI = 35.1% to 50.6%, P < .001) and liver metastases (47.0%, 95% CI = 41.0% to 53.0%, P < .001) compared with central nervous system metastases (23.3%, 95% CI = 16.0% to 32.6%).

Conclusions

Receptor conversion for ERα, PR, and HER2 occurs frequently in the course of disease progression in breast cancer. Large prospective studies assessing the impact of receptor conversion on treatment efficacy and survival are needed. Meanwhile, reassessing receptor status in metastases is strongly encouraged.

Discordances in ER, PR, and HER2 between primary breast cancer and brain metastasis

When distant metastases are discovered, it is important to determine receptor profiles of these lesions through histologic examination. However, brain metastasis sites are difficult to reach to be routinely biopsied. The purpose of this study was to determine expression profiles of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in breast cancer brain metastasis (BCBM) and the existence of discordance between primary breast cancer and brain metastasis. A total of 37 patients who underwent craniotomies for metastatic brain tumors arising from breast cancer at National Cancer Center (NCC) of Korea between 2002 and 2014 were retrospectively reviewed. Clinicopathologic data were collected from electronic medical records. Receptor profiles of primary breast cancer and brain metastasis in each patient were identified. Data of ER, PR, and HER2 expression in brain metastasis were available in electronic medical records for 21 (56.8%) of 37 cases. Results of ER, PR, and HER2 expression were positive in 47.6, 42.9, and 38.1% of patients with brain metastasis, respectively. Receptor conversion occurred in 11 (52.4%) of 21 patients (for ER, 9.5%; for PR, 38.1%; for HER2, 23.8%). Overall survival was longer in patients with concordant receptor expression patterns between primary breast cancer and brain lesion compared to that in patients with discordant patterns. However, such difference was not statistically significant (discordant vs. concordant median survival: 19.2 versus 31.1 months, p = 0.181). Receptor conversion in BCBMs was observed in over 50% of Korean patients used in this study. HER2 conversion was observed in 23.8% of patients in this study. Therefore, if resistance to anti-HER2 treatment is suspected in patients with BCBM, biopsy is needed to determine receptor profiles of brain lesion.

Discrepancies between biomarkers of primary breast cancer and subsequent brain metastases: an international multicenter study

PURPOSE

Discordances between the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), expression between primary breast tumors and their subsequent brain metastases (BM) were investigated in breast cancer patients.

METHODS

We collected retrospective data from 11 institutions in 8 countries in a predefined-standardized format. Receptor status (positive or negative) was determined according to institutional guidelines (immunohistochemically and/or fluorescence in situ hybridization). The study was subject to each institution's ethical research committee.

RESULTS

A total of 167 breast cancer patients with BM were included. 25 patients out of 129 with a complete receptor information from both primary tumor and BM (ER, PR, HER2) available, had a change in receptor status: 7 of 26 (27%) ER/PR-positive/HER2-negative primaries (3 gained HER2; 4 lost expression of ER/PR); 10 of 31 (32%) ER/PR-positive/HER2-positive primaries (4 lost ER/PR only; 3 lost HER2 only; 3 lost both ER/PR and HER2); one of 33 (3%) ER/PR-negative receptor/HER2-positive primaries (gained ER); and 7 of 39 (18%) triple-negative primaries (5 gained ER/PR and 2 gained HER2).

CONCLUSIONS

The majority of breast cancer patients with BM in this series had primary HER2-enriched tumors, followed by those with a triple-negative profile. One out of 5 patients had a receptor discrepancy between the primary tumor and subsequent BM. Therefore, we advise receptor status assessment of BM in all breast cancer patients with available histology as it may have significant implications for therapy.

Loss of steroid hormone receptors is common in malignant pleural and peritoneal effusions of breast cancer patients treated with endocrine therapy

Discordance in estrogen receptor alpha (ERα), progesterone receptor (PR), androgen receptor (AR) and human epidermal growth factor receptor 2 (HER2) status between primary breast cancers and solid distant metastases (“conversion”) has been reported previously. Even though metastatic spread to the peritoneal and pleural cavities occurs frequently and is associated with high mortality, the rate of receptor conversion and the prognostic implications thereof remain elusive.

We therefore determined receptor conversion in 91 effusion metastases (78 pleural, 13 peritoneal effusions) of 69 patients by immunohistochemistry (IHC) and in situ hybridization. Data were coupled to clinical variables and treatment history.

ERα, PR and AR receptor status converted from positive in the primary tumor to negative in the effusion metastases or vice versa in 25-30%, 30-35% and 46-51% of cases for the 1% and 10% thresholds for positivity, respectively. 19-25% of patients converted clinically relevant from “ERα+ or PR+” to ERα-/PR- and 3-4% from ERα-/PR- to “ERα+ or PR+”. For HER2, conversion was observed in 6% of cases. Importantly, receptor conversion for ERα (p = 0.058) and AR (p < 0.001) was more often seen in patients adjuvantly treated with endocrine therapy. Analogous to this observation, HER2-loss was more frequent in patients adjuvantly treated with trastuzumab (p < 0.001).

Alike solid distant metastases, receptor conversion for ERα, PR, AR and HER2 is a frequent phenomenon in peritoneal and pleural effusion metastases. Adjuvant endocrine and trastuzumab therapy imposes an evolutionary selection pressure on the tumor, leading to receptor loss in effusion metastases. Determination of receptor status in malignant effusion specimens will facilitate endocrine treatment decision-making at this lethal state of the disease, and is hence recommended whenever possible.

Estrogen, progesterone, and HER2/neu receptor discordance between primary and metastatic breast tumours-a review

Discordance in estrogen (ER), progesterone (PR), and HER2/neu status between primary breast tumours and metastatic disease is well recognized. In this review, we highlight how receptor discordance between primary tumours and paired metastasis can help elucidate the mechanism of metastasis but can also effect patient management and the design of future trials. Discordance rates and ranges were available from 47 studies (3384 matched primary and metastatic pairs) reporting ER, PR, and HER2/neu expression for both primary and metastatic sites. Median discordance rates for ER, PR, and HER2/neu were 14 % (range 0-67 %, IQR 9-25 %), 21 % (range 0-62 %, IQR 15-41 %), and 10 % (range 0-44 %, IQR 4-17 %), respectively. Loss of receptor expression was more common (9.17 %) than gain (4.51 %). Discordance rates varied amongst site of metastasis with ER discordance being highest in bone metastases suggesting that discordance is a true biological phenomenon. Discordance rates vary for both the biomarker and the metastatic site. Loss of expression is more common than gain. This can affect patient management as it can lead to a reduction in both the efficacy and availability of potential therapeutic agents. Future studies are recommended to explore both the mechanisms of discordance as well as its impact on patient outcome and management.

Comparison of HER2 Expression in Primary Tumor and Disseminated Tumor Cells in the Bone Marrow of Breast Cancer Patients

OBJECTIVE

The aim of this study was to measure the human epidermal growth factor receptor 2 (HER2) status of disseminated tumor cells (DTCs) from bone marrow (BM) aspirates and to assess correspondence or discrepancy with the primary tumor.

METHODS

DTCs were isolated from the BM of 156 breast cancer patients. Cytokeratin-positive DTCs were further analyzed by the chromogenic in situ hybridization method to detect HER2 gene amplification.

RESULTS

A significant correlation (p = 0.021) was found between the HER2 status of DTCs and the primary tumors. Sixty-one (68.5%) patients had a corresponding status. However, a shift of phenotype between primary tumor and DTCs was found in the remaining patients.

CONCLUSION

This study showed a significant grade of discordance of the HER2 status between primary tumors and DTCs in the BM of a relevant subgroup of patients. Detection of HER2 amplification on DTCs could therefore help to better stratify patients for a more tailored therapy, since they would benefit from a HER2-targeted therapy.

Changing molecular profile of brain metastases compared with matched breast primary cancers and impact on clinical outcomes

Background:

Breast cancer commonly metastasises to the brain, but little is known about changes in the molecular profile of the brain secondaries and impact on clinical outcomes.

Methods:

Patients with samples from brain metastases and matched breast cancers were included. Immunohistochemical analysis for oestrogen receptor, progesterone receptor, p27kip1, cyclin D1, epidermal growth factor receptor, insulin like growth factor 1, insulin like growth factor 1 receptor, vascular endothelial growth factor A, transforming growth factor-β and HER2 receptor was performed. Borderline HER2 results were analysed by fluorescent in situ hybridisation. Levels of expression were compared, with review of effect on clinical outcomes.

Results:

A total of 41 patients were included. Of the patients, 20% had a change in oestrogen receptor or HER2 in their brain metastasis that could affect therapeutic decisions. There were statistically significant rises in brain metastases for p27kip1 (P=0.023) and cyclin D1 (P=0.030) and a fall in vascular endothelial growth factor A (P=0.012). Overall survival from the time of metastasis increased significantly with oestrogen receptor-positive (P=0.005) and progesterone receptor-positive (P=0.013) brain lesions and with a longer duration from diagnosis of the breast primary (P<0.001).

Conclusions:

In this cohort there were phenotypic differences in metastatic brain tumours compared with matched primary breast tumours. These could be relevant for aetiology, and have an impact on prognostication, current and future therapies.

(64)Cu-DOTA-trastuzumab PET imaging and HER2 specificity of brain metastases in HER2-positive breast cancer patients

Background

The purpose of this study was to determine whether brain metastases from HER2-positive breast cancer could be detected noninvasively using positron emission tomography (PET) with ⁶⁴Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-trastuzumab.

Methods

PET was performed on five patients with brain metastases from HER2-positive breast cancer, at 24 or 48 h after the injection of approximately 130 MBq of the probe ⁶⁴Cu-DOTA-trastuzumab. Radioactivity in metastatic brain tumors was evaluated based on PET images in five patients. Autoradiography, immunohistochemistry (IHC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis were performed in one surgical case to confirm HER2 specificity of ⁶⁴Cu-DOTA-trastuzumab.

Results

Metastatic brain lesions could be visualized by ⁶⁴Cu-DOTA-trastuzumab PET in all of five cases, which might indicated that trastuzumab passes through the blood-brain barrier (BBB). The HER2 specificity of ⁶⁴Cu-DOTA-trastuzumab was demonstrated in one patient by autoradiography, immunohistochemistry, and LC-MS/MS.

Conclusions

Cu-DOTA-trastuzumab PET could be a potential noninvasive procedure for serial identification of metastatic brain lesions in patients with HER2-positive breast cancer.

Trial registration

UMIN000004170

Quantitative HER2 and p95HER2 levels in primary breast cancers and matched brain metastases

BACKGROUND

Patients with advanced breast cancer positive for human epidermal growth factor receptor 2 (HER2) are at high risk for brain metastasis (BM). The prevalence and significance of expression of HER2 and its truncated form p95HER2 (p95) in BM is unknown.

METHODS

Seventy-five pairs of formalin-fixed paraffin-embedded samples from matched primary breast cancers (PBCs) and BM were assayed for quantitative p95 and HER2-total (H2T) protein expression using the p95 VeraTag and HERmark assays, respectively.

RESULTS

There was a net increase in p95 and H2T expression in BM relative to the matched PBC (median 1.5-fold, P = .0007 and 2.1-fold, P < .0001, respectively). Cases with H2T-positive tumors were more likely to have the largest (≥5-fold) increase in p95 (odds ratio = 6.3, P = .018). P95 positivity in PBC correlated with progression-free survival (hazard ratio [HR] = 2.2, P = .013), trended with shorter time to BM (HR = 1.8, P = .070), and correlated with overall survival (HR = 2.1, P = .042). P95 positivity in BM correlated with time to BM (HR = 2.0, P = .016) but did not correlate with overall survival from the time of BM diagnosis (HR = 1.2, P = .61).

CONCLUSIONS

This is the first study of quantitative p95 and HER2 expression in matched PBC and BM. BM of breast cancer shows significant increases in expression of both biomarkers compared with matched PBC. These data provide a rationale for future correlative studies on p95 and HER2 levels in BM.

Extended trastuzumab therapy improves the survival of HER2-positive breast cancer patients following surgery and radiotherapy for brain metastases

Brain metastases usually present late during the course of breast cancer and are associated with an unfavorable prognosis. It was previously demonstrated that the status of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor type 2 (HER2) may be altered in the time window between the emergence of the primary breast tumor and the development of metastases. The aim of this study was to compare the expression of ER, PR and HER2 in pathology samples of primary breast cancer and brain metastases in order to evaluate whether previously administered therapy was able to modify this status and determine whether biomarker alterations affect prognosis after the development of brain metastases. Data were collected from 62 patients who were initially diagnosed with breast cancer that had metastasized to the brain. The ER, PR and HER2 status of the samples from the primary tumors and the brain metastases was determined. Differences in the immunohistochemical profiles of ER, PR or HER2 between the primary tumors and the brain metastases in 17 patients (29.3%) were identified. The patients with HER2-positive brain metastases who received trastuzumab had no leptomeningeal metastases and exhibited a longer survival time after brain metastases compared to the HER2-positive patients who did not receive trastuzumab and the patients with HER2-negative brain metastases (P=0.0005). Our results suggested that the patients treated with trastuzumab following surgery and radiotherapy for brain metastases exhibited a better prognosis. Thus, the HER2 status in brain metastases requires re-evaluation and extended trastuzumab therapy is recommended after brain metastases.

Conversion of epidermal growth factor receptor 2 and hormone receptor expression in breast cancer metastases to the brain

Introduction

We investigated the status of estrogen receptor alpha (ERα), progesterone receptor (PR), and epidermal growth factor receptor 2 (HER2) in primary tumor and in the corresponding brain metastases in a consecutive series of breast cancer patients. Additionally, we studied factors potentially influencing conversion and evaluated its association with survival.

Methods

The study group included 120 breast cancer patients. ERα, PR, and HER2 status in primary tumors and in matched brain metastases was determined centrally by immunohistochemistry and/or fluorescence in situ hybridization.

Results

Using the Allred score of ≥ 3 as a threshold, conversion of ERα and PR in brain metastases occurred in 29% of cases for both receptors, mostly from positive to negative. Conversion of HER2 occurred in 14% of patients and was more balanced either way. Time to brain relapse and the use of chemotherapy or trastuzumab did not influence conversion, whereas endocrine therapy induced conversion of ERα (P = 0.021) and PR (P = 0.001), mainly towards their loss. Receptor conversion had no significant impact on survival.

Conclusions

Receptor conversion, particularly loss of hormone receptors, is a common event in brain metastases from breast cancer, and endocrine therapy may increase its incidence. Receptor conversion does not significantly affect survival.

A subset of breast cancer predisposes to brain metastasis

This study evaluated the expression of biological markers of breast cancers with brain metastases. Eighteen paired tumors were assessed, with 42 non-brain-metastasizing breast cancers that were stained with ER, PR, HER2, CK5/6, p63, and Ki67, and were also classified into intrinsic subtypes. The expression patterns between the breast tumors with brain metastases were compared to the brain metastases and the controls. Breast cancers with brain metastases were of higher grade and showed higher incidence of lymph node metastases at initial diagnosis and higher EGFR, p63, and Ki67 expression. In the group of breast cancers with brain metastases, the brain metastases showed higher HER2, CK5/6, and Ki67 expression compared to the breast primaries. There was also a higher incidence of basal subtype and a lower incidence of luminal subtype. When tumors metastasized, changes in hormonal receptor (22%) and HER2 (6%) status were observed. We concluded that breast cancers with higher grade, lymph node involvement at diagnosis, high EGFR, p63, and Ki67 expression, and of basal subtype were at higher risk for brain metastases, and that both hormonal receptors and HER2 status may change in brain metastases.

Trastuzumab clears HER2/neu-positive isolated tumor cells from bone marrow in primary breast cancer patients

PURPOSE

Isolated tumor cells (ITC) in the bone marrow of breast cancer patients increase the risk of recurrence and decrease survival, both at primary diagnosis and during follow-up. We tested the efficacy of trastuzumab in clearing HER2/neu-positive ITC from the marrow of patients completing primary treatment.

METHODS

Ten recurrence-free patients with persistent HER2/neu-positive ITC after routine adjuvant treatment received trastuzumab 6 mg/kg q3w for 12 months in a non-randomized pilot phase II interventional study. Bone marrow ITC HER2/neu status was evaluated at baseline, after treatment for 3, 6 and 12 months, and yearly thereafter, in combination with clinical follow-up. Median follow-up was 23 (15-64) months after baseline bone marrow aspiration.

RESULTS

Trastuzumab for 12 months eradicated HER2/neu-positive ITC from bone marrow in all patients (P = 0.002) and significantly reduced the number of ITC-positive patients (P = 0.031). However, HER2/neu-negative ITC persisted in three patients immediately after treatment and were detected at yearly bone marrow aspiration in five patients. Two patients with ITC counts ≥5 at yearly follow-up developed metastases and one died.

CONCLUSION

This is the first evidence that trastuzumab is effective in clearing HER2/neu-positive cells from bone marrow during recurrence-free follow-up in breast cancer patients. It also suggests, thanks to the antigen shift phenomenon, an important prognostic role for HER2/neu expression on marrow ITC as a real-time biopsy. However, treatment was mainly effective in patients with HER2/neu-positive ITC. Given the heterogeneity of minimal residual disease, these patients might benefit from a combination of targeted treatment approaches.

Survival among women with triple receptor-negative breast cancer and brain metastases

BACKGROUND

The purpose of this study was to determine the incidence of and survival following brain metastases among women with triple receptor-negative breast cancer.

PATIENTS AND METHODS

In all, 679 patients with nonmetastatic triple receptor-negative breast cancer diagnosed from 1980 to 2006 were identified. Cumulative incidence of brain metastases was computed. Cox proportional hazards models were fitted to explore factors that predict for development of brain metastases. Survival was computed using the Kaplan-Meier product limit method.

RESULTS

Median follow-up was 26.9 months. In all, 42 (6.2%) patients developed brain metastases with a cumulative incidence at 2 and 5 years of 5.6% [95% confidence interval (CI) 3.8% to 7.9%] and 9.6% (95% CI 6.8% to 13%), respectively. A total of 24 (3.5%) patients developed brain metastases as the first site of recurrence with cumulative incidence at 2 and 5 years of 2.0% (95% CI 2.6% to 6.0%) and 4.9% (95% CI 3.2% to 7.0%), respectively. In the multivariable model, no specific factor was observed to be significantly associated with time to brain metastases. Median survival for all patients who developed brain metastases and those who developed brain metastases as the first site of recurrence was 2.9 months (95% CI 2.0-7.6 months) and 5.8 months (95% CI 1.7-11.0 months), respectively.

CONCLUSION

In this single-institutional study, patients with nonmetastatic triple receptor-negative breast tumors have a high early incidence of brain metastases associated with poor survival and maybe an ideal cohort to target brain metastases preventive strategies.