Invasive lobular breast cancer and its variants: how special are they for systemic therapy decisions?

Characteristics and clinical outcomes of breast cancer in young BRCA carriers according to tumor histology

BACKGROUND

Young women with breast cancer (BC) have an increased chance of carrying germline BRCA pathogenic variants (PVs). Limited data exist on the prognostic impact of tumor histology (i.e. ductal versus lobular) in hereditary breast cancer.

METHODS

This multicenter retrospective cohort study included women aged ≤40 years with early-stage breast cancer diagnosed between January 2000 and December 2020 and known to carry germline PVs in BRCA1/2. Histology was locally assessed in each center. The Kaplan-Meier method and Cox regression analysis were used to assess disease-free survival and overall survival.

RESULTS

Of 4628 patients included from 78 centers worldwide, 3969 (86%) had pure ductal, 135 (3%) pure lobular, and 524 (11%) other histologies. Compared with ductal tumors, lobular tumors were more often grade 1/2 (57.7% versus 22.1%), stage III (29.6% versus 18.5%), and luminal A-like (42.2% versus 12.2%). Lobular tumors were more often associated with BRCA2 PVs (71.1% BRCA2), while ductal tumors were more often associated with BRCA1 PVs (65.7% BRCA1). Patients with lobular tumors more often had mastectomy (68.9% versus 58.3%), and less often received chemotherapy (83.7% versus 92.9%). With a median follow-up of 7.8 years, no significant differences were observed in disease-free survival (adjusted hazard ratio 1.01, 95% confidence interval 0.74-1.37) or overall survival (hazard ratio 0.96, 95% confidence interval 0.62-1.50) between patients with ductal versus lobular tumors. No significant survival differences were observed according to specific BRCA gene, breast cancer subtype, or body mass index.

CONCLUSIONS

In this large global cohort of young BRCA carriers with breast cancer, the incidence of pure lobular histology was low and associated with higher disease stage at diagnosis, luminal-like disease and BRCA2 PVs. Histology did not appear to impact prognosis.

Ultrasound-based deep learning radiomics nomogram for differentiating mass mastitis from invasive breast cancer

BACKGROUND

The purpose of this study is to develop and validate the potential value of the deep learning radiomics nomogram (DLRN) based on ultrasound to differentiate mass mastitis (MM) and invasive breast cancer (IBC).

METHODS

50 cases of MM and 180 cases of IBC with ultrasound Breast Imaging Reporting and Data System 4 category were recruited (training cohort, n = 161, validation cohort, n = 69). Based on PyRadiomics and ResNet50 extractors, radiomics and deep learning features were extracted, respectively. Based on supervised machine learning methods such as logistic regression, random forest, and support vector machine, as well as unsupervised machine learning methods using K-means clustering analysis, the differences in features between MM and IBC were analyzed to develop DLRN. The performance of DLRN had been evaluated by receiver operating characteristic curve, calibration, and clinical practicality.

RESULTS

Supervised machine learning results showed that compared with radiomics models, especially random forest models, deep learning models were better at recognizing MM and IBC. The area under the curve (AUC) of the validation cohort was 0.84, the accuracy was 0.83, the sensitivity was 0.73, and the specificity was 0.83. Compared to radiomics or deep learning models, DLRN even further improved discrimination ability (AUC of 0.90 and 0.90, accuracy of 0.83 and 0.88 for training and validation cohorts), which had better clinical benefits and good calibratability. In addition, the information heterogeneity of deep learning features in MM and IBC was validated again through unsupervised machine learning clustering analysis, indicating that MM had a unique features phenotype.

CONCLUSION

The DLRN developed based on radiomics and deep learning features of ultrasound images has potential clinical value in effectively distinguishing between MM and IBC. DLRN breaks through visual limitations and quantifies more image information related to MM based on computers, further utilizing machine learning to effectively utilize this information for clinical decision-making. As DLRN becomes an autonomous screening system, it will improve the recognition rate of MM in grassroots hospitals and reduce the possibility of incorrect treatment and overtreatment.

Invasive lobular breast cancer: Focus on prevention, genetics, diagnosis, and treatment

Invasive lobular cancer (ILC) is the most common of the breast cancer special types, accounting for up to 15% of all breast malignancies. The distinctive biological features of ILC include the loss of the cell adhesion molecule E-cadherin, which drives the tumor's peculiar discohesive growth pattern, with cells arranged in single file and dispersed throughout the stroma. Typically, such tumors originate in the lobules, are more commonly bilateral compared to invasive ductal cancer (IDC) and require a more accurate diagnostic examination through imaging. They are luminal in molecular subtype, and exhibit estrogen and progesterone receptor positivity and HER2 negativity, thus presenting a more unpredictable response to neoadjuvant therapies. There has been a significant increase in research focused on this distinctive breast cancer subtype, including studies on its pathology, its clinical and surgical management, and the high-resolution definition of its genomic profile, as well as the development of new therapeutic perspectives. This review will summarize the heterogeneous pattern of this unique disease, focusing on challenges in its comprehensive clinical management and on future insights and research objectives.

Pathway-based signatures predict patient outcome, chemotherapy benefit and synthetic lethal dependencies in invasive lobular breast cancer

BACKGROUND

Invasive Lobular Carcinoma (ILC) is a morphologically distinct breast cancer subtype that represents up to 15% of all breast cancers. Compared to Invasive Breast Carcinoma of No Special Type (IBC-NST), ILCs exhibit poorer long-term outcome and a unique pattern of metastasis. Despite these differences, the systematic discovery of robust prognostic biomarkers and therapeutically actionable molecular pathways in ILC remains limited.

METHODS

Pathway-centric multivariable models using statistical machine learning were developed and tested in seven retrospective clinico-genomic cohorts (n = 996). Further external validation was performed using a new RNA-Seq clinical cohort of aggressive ILCs (n = 48).

RESULTS AND CONCLUSIONS

mRNA dysregulation scores of 25 pathways were strongly prognostic in ILC (FDR-adjusted P < 0.05). Of these, three pathways including Cell-cell communication, Innate immune system and Smooth muscle contraction were also independent predictors of chemotherapy response. To aggregate these findings, a multivariable machine learning predictor called PSILC was developed and successfully validated for predicting overall and metastasis-free survival in ILC. Integration of PSILC with CRISPR-Cas9 screening data from breast cancer cell lines revealed 16 candidate therapeutic targets that were synthetic lethal with high-risk ILCs. This study provides interpretable prognostic and predictive biomarkers of ILC which could serve as the starting points for targeted drug discovery for this disease.

Metastatic Occult Primary Lobular Breast Cancer: A Case Report

Breast cancer is the most common malignancy diagnosed in women. Invasive lobular breast cancer (ILC) is the second most common histologic subtype after invasive ductal carcinoma. Metastatic occult primary breast cancer, although rare, is a well-known clinical entity that usually presents with axillary lymphadenopathy without a detectable breast tumour. A perimenopausal woman in her 50s presented with abdominal pain, fatigue, and weight loss. Imaging showed peritoneal carcinomatosis with ascites, ovarian masses, and a lesion in the ascending colon. Gastric and colon biopsies showed infiltration from lobular breast cancer. Diagnostic workup, including mammography, breast ultrasound, and breast MRI, showed no evidence of breast pathology or axillary lymphadenopathy. First-line treatment with goserelin, letrozole, and palbociclib commenced with clinical improvement and radiological response. This case illustrates the challenges faced by clinicians in the diagnosis and treatment of lobular breast cancer without an identifiable primary lesion or axillary lymphadenopathy.

Metastatic profiles and survival differences between infiltrating ductal carcinoma and infiltrating lobular carcinoma in invasive breast cancer

BACKGROUND

In this study, we conducted a comprehensive evaluation of metastatic profiles and survival outcomes in patients with infiltrating ductal carcinoma (IDC) and infiltrating lobular carcinoma (ILC) treated at our university hospital center.

METHODS

We collected and analyzed data from all patients diagnosed with invasive breast cancer at our center between January 1, 2007, and 31 December 2014. We specifically compared three subgroups: patients with IDC, patients with ILC and patients with mixed carcinoma, which is a combination of IDC and ILC.

RESULTS

Among the 1963 patients treated for invasive breast cancer in our center during the study period, 1435 had IDC, 466 had ILC, and 59 had mixed carcinoma. The incidence of patients with at least one positive axillary lymph node differed significantly: 40 % for IDC, 36 % for ILC, and 45 % for mixed carcinoma (p = 0.001). However, there was no significant difference in the mean number of positive nodes (p = 0.1633). The occurrence of distant metastases was lower in patients with ILC (p = 0.04), particularly in the case of brain metastases (p = 0.01), although there was no difference in bone or visceral metastatic sites. Patients with ILC exhibited a longer mean time to metastasis from the initial diagnosis of invasive breast carcinoma. Overall survival (p = 0.0525) and survival without locoregional recurrence (p = 0.026) were significantly different. Specifically, the 5-year overall survival rates for IDC, ILC, and mixed carcinoma were approximately 95 %. Distance metastatic-free survival at 5 years was 85 % for IDC, 91 % for ILC, and 87 % for mixed carcinoma (p = 0.00506).

CONCLUSION

Our findings indicate variations in the distribution of distant metastatic sites among patients with IDC, ILC, and mixed carcinoma, as well as differences in survival outcomes. This study sheds light on the unique characteristics and clinical implications associated with these two distinct subtypes of invasive breast cancer.

HER2-positive invasive lobular carcinoma: a rare breast cancer which may not necessarily require anti-HER2 therapy. A population-based study

BACKGROUND

HER2-positive (HER2 +) invasive lobular breast cancer (ILC) is rare and poorly characterised. In particular, patient outcomes compared to those associated with HER2 + invasive ductal cancer (IDC) and HER2-negative (HER2 -) ILC, as well as the benefits of anti-HER2 therapy, are not well established.

METHODS

We analysed the data from the Côte d'Or Registry of Breast and Gynaecological Cancers (France) for all patients diagnosed with early-stage HER2 + ILC (62 cases), HER2 + IDC (833 cases) and HER2 - ILC (685 cases) between 1998 and 2015 to compare overall and disease-free survival (OS and DFS) between these groups in correlation with anti-HER2 therapy.

RESULTS

ILCs were associated with older age, larger tumours, lower histological grades, higher hormonal receptor positivity rates and multifocality, and more common endocrine therapy. OS and DFS between the three groups did not differ. We found that anti-HER2 therapy was associated with a survival benefit in patients with HER2 + IDC. In contrast, the survival of HER2 + ILC patients was not improved by anti-HER2 treatment, remaining close to that of HER2 - ILC patients.

CONCLUSION

HER2 + ILC seems not to be associated with better outcomes than HER2 + IDC but may not differ from HER2 - ILC in terms of survival.

Histology-based survival outcomes in hormone receptor-positive metastatic breast cancer treated with targeted therapies

The addition of targeted therapies (TT) to endocrine therapy (ET) has improved the outcomes of patients with HR-positive, HER2-negative metastatic breast cancer (mBC). However, it is unknown whether patients with invasive lobular carcinoma (ILC) or mixed invasive ductal and lobular carcinoma (mixed) histologies experience the same magnitude of benefit from this therapy as those with invasive ductal carcinoma (IDC). We aim to determine whether patients with IDC, ILC, and mixed HR+/HER2- mBC derive similar benefit from the addition of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is), mammalian target of rapamycin inhibitor (mTORi), and phosphoinositide 3-kinase inhibitor (PI3Ki) to ET in HR+/HER2- mBC. We conducted an observational, population-based investigation using data from the MD Anderson prospectively collected database. We conducted a histology-based analysis of progression-free survival (PFS) and overall survival (OS) durations in 3784 patients with HR+/HER2- mBC who were treated with TT plus ET between January 1, 2010, and December 31, 2021. Out of the 3784 patients, 2975 were included in the final analysis. Of these, 2249 received CDK4/6is (81% IDC, 15% ILC, and 4% mixed), 1027 received everolimus (82% IDC, 14% ILC, and 4% mixed) and 49 received alpelisib (81% IDC and 19% ILC). The addition of targeted therapy to ET did not result in statistically significant differences in PFS or OS duration among patients with IDC, ILC, and mixed HR+/HER2- mBC. We concluded that for patients with HR+/HER2- mBC, the addition of TT to ET leads to a similar magnitude of benefit, irrespective of histology.

Asymptomatic uterine metastasis of breast cancer: Case report and literature review

RATIONALE

Uterine metastasis from breast cancer is extremely rare. Asymptomatic patients with cervical metastases from breast cancer are rarer and more likely to be missed. We present an asymptomatic patient with breast cancer metastasized to the uterus and share opinions on diagnosing and treating for this kind of cases.

PATIENT CONCERNS

We present the case of a 64-year-old woman who was diagnosed with both breast cancer and uterine fibroids after examination. She had no symptoms of gynecological disease during breast cancer treatment. A positron emission tomography/computed tomography (PET/CT) scan was performed during reexamination, revealing multiple metastases of the bone throughout the body and an abnormal hypermetabolic mass in the uterus. It was later confirmed as uterine metastasis by pathology.

DIAGNOSIS

A diagnosis of metastatic breast invasive lobular carcinoma was established after a uterine curettage.

INTERVENTIONS AND OUTCOMES

Treatment of the uterine metastasis included systemic chemotherapy, total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH and BSO), postoperative radiotherapy, and postoperative chemotherapy. The patient eventually refused further treatment for personal reasons and died at home.

LESSONS

Breast cancer metastases to the uterus are very rare and further research is needed for their diagnosis and treatment. During reexamination of breast cancer patients, clinicians must be alert to metastasis to gynecologic organs. This is particularly important in hormone receptor-positive patients with asymptomatic distant metastasis.

Risk of metachronous contralateral breast cancer in patients with primary invasive lobular breast cancer: Results from a nationwide cohort

Lobular primary breast cancer (PBC) histology has been proposed as a risk factor for contralateral breast cancer (CBC), but results have been inconsistent. We investigated CBC risk and the impact of systemic therapy in lobular versus ductal PBC. Further, CBC characteristics following these histologic subtypes were explored. We selected 74,373 women diagnosed between 2003 and 2010 with stage I-III invasive PBC from the nationwide Netherlands Cancer Registry. We assessed absolute risk of CBC taking into account competing risks among those with lobular (n = 8903), lobular mixed with other types (n = 3512), versus ductal (n = 62,230) histology. Hazard ratios (HR) for CBC were estimated in a cause-specific Cox model, adjusting for age at PBC diagnosis, radiotherapy, chemotherapy and/or endocrine therapy. Multivariable HRs for CBC were 1.18 (95% CI: 1.04-1.33) for lobular and 1.37 (95% CI: 1.16-1.63) for lobular mixed versus ductal PBC. Ten-year cumulative CBC incidences in patients with lobular, lobular mixed versus ductal PBC were 3.2%, 3.6% versus 2.8% when treated with systemic therapy and 6.6%, 7.7% versus 5.6% in patients without systemic therapy, respectively. Metachronous CBCs were diagnosed in a less favourable stage in 19%, 26% and 23% and less favourable differentiation grade in 22%, 33% and 27% than the PBCs of patients with lobular, lobular mixed and ductal PBC, respectively. In conclusion, lobular and lobular mixed PBC histology are associated with modestly increased CBC risk. Personalised CBC risk assessment needs to consider PBC histology, including systemic treatment administration. The impact on prognosis of CBCs with unfavourable characteristics warrants further evaluation.

ROSALINE: a phase II, neoadjuvant study targeting ROS1 in combination with endocrine therapy in invasive lobular carcinoma of the breast

Invasive lobular carcinoma (ILC) is the most common histologic subtype of breast cancer after invasive ductal carcinoma (i.e., no special type [NST]). ILC differs from NST in clinical presentation, site-specific metastases and response to conventional therapies. Loss of E-cadherin protein expression, due to alterations in its encoding gene CDH1, is the most frequent oncogenic event in ILC. Synthetic lethality approaches have shown promising antitumor effects of ROS1 inhibitors in models of E-cadherin-defective breast cancer in in vivo studies and provide the rationale for testing their clinical activity in patients with ILC. Entrectinib is a tyrosine kinase inhibitor targeting TRK, ROS1 and ALK tyrosine kinases. Here, the authors present ROSALINE (NCT04551495), a phase II study testing neoadjuvant entrectinib and endocrine therapy in women with estrogen receptor-positive, HER2-negative early ILC.

Loss of E-cadherin leads to Id2-dependent inhibition of cell cycle progression in metastatic lobular breast cancer

Invasive lobular breast carcinoma (ILC) is characterized by proliferative indolence and long-term latency relapses. This study aimed to identify how disseminating ILC cells control the balance between quiescence and cell cycle re-entry. In the absence of anchorage, ILC cells undergo a sustained cell cycle arrest in G0/G1 while maintaining viability. From the genes that are upregulated in anchorage independent ILC cells, we selected Inhibitor of DNA binding 2 (Id2), a mediator of cell cycle progression. Using loss-of-function experiments, we demonstrate that Id2 is essential for anchorage independent survival (anoikis resistance) in vitro and lung colonization in mice. Importantly, we find that under anchorage independent conditions, E-cadherin loss promotes expression of Id2 in multiple mouse and (organotypic) human models of ILC, an event that is caused by a direct p120-catenin/Kaiso-dependent transcriptional de-repression of the canonical Kaiso binding sequence TCCTGCNA. Conversely, stable inducible restoration of E-cadherin expression in the ILC cell line SUM44PE inhibits Id2 expression and anoikis resistance. We show evidence that Id2 accumulates in the cytosol, where it induces a sustained and CDK4/6-dependent G0/G1 cell cycle arrest through interaction with hypo-phosphorylated Rb. Finally, we find that Id2 is indeed enriched in ILC when compared to other breast cancers, and confirm cytosolic Id2 protein expression in primary ILC samples. In sum, we have linked mutational inactivation of E-cadherin to direct inhibition of cell cycle progression. Our work indicates that loss of E-cadherin and subsequent expression of Id2 drive indolence and dissemination of ILC. As such, E-cadherin and Id2 are promising candidates to stratify low and intermediate grade invasive breast cancers for the use of clinical cell cycle intervention drugs.

Impact of lobular versus ductal histology on overall survival in metastatic breast cancer: a French retrospective multicentre cohort study

BACKGROUND

The impact of the histological lobular subtype on overall survival (OS) in metastatic breast cancer (MBC) is still under debate, with very few data available.

PATIENTS AND METHODS

Using the French national multicentre Epidemiological Strategy and Medico Economics [ESME]) data platform, the primary objective was to compare the OS of patients with invasive lobular carcinoma (ILC) versus invasive ductal carcinoma (IDC) MBC, with adjustment on the main prognostic factors using two approaches: multivariable analysis and matching with a propensity score. Secondary objectives were to compare first-line progression-free survival (PFS1) and describe patients and tumour characteristics.

RESULTS

Of the 16,703 patients with MBC in the ESME database, 13,111 met all inclusion criteria for the present analysis. One-thousand eight-hundred and four (13.8%) patients had ILC and 11.307 (86.2%) IDC. In the multivariable analysis, patients with ILC had a worse OS [hazard ratio (HR): 1.31; 95%CI 1.20-1.42; p < 0.0001] and a worse PFS1 (HR: 1.15; 95%CI 1.07-1.22; p < 0.0001) as compared with those with IDC, independently of hormone receptor and HER2 status. Interestingly, OS was better (HR 0.79; 95% confidence interval [CI] 0.64-0.98; p = 0.0302), worse (HR: 1.17; 95%CI 1.08-1.27; p = 0.0001) or similar (HR: 0.88; 95%CI 0.67-1.15; p = 0.3455) in patients with ILC with triple-negative, hormone receptor-positive/HER2-negative and HER2-positive MBC, respectively, compared with patients with IDC.

CONCLUSION

Lobular histology is an independent adverse prognostic factor among women with MBC. ILC MBC could be considered a specific entity. Dedicated prospective studies are needed to tailor the management of these patients.

Adjuvant chemotherapy in patients with invasive lobular carcinoma and use of the 21-gene recurrence score: A National Cancer Database analysis

BACKGROUND

Invasive lobular carcinoma (ILC) is traditionally considered less responsive to chemotherapy. Although the Oncotype recurrence score (RS) has been validated to identify high-risk patients who benefit from chemotherapy, some studies have questioned its relevance in patients with ILC. The objective of this study was to better characterize potential use of the RS in these patients.

METHODS

The National Cancer Database was used to identify women with stage I through III, T1 through T3, N0 or N1, hormone receptor-positive, HER2-negative ILC or invasive ductal carcinoma (IDC) who had an available RS between 2010 and 2016. Multivariable Cox regression was used to model the effect of variables on 5-year overall survival (OS). The Kaplan-Meier method was used to estimate OS according to the RS, nodal status, and chemotherapy.

RESULTS

In total, 15,763 patients with ILC and 100,070 with IDC were identified. The mean age of patients with ILC and IDC was 59.2 ± 9.1 and 57.2 ± 9.8, respectively. A lower percentage of patients with ILC versus those with IDC had a high RS, defined as >25 (6.6% vs 16.0%; P < .0001). ILC patients with a high RS who had N0 or N1 disease received approximately 10% less chemotherapy compared with similar patients who had IDC. The results indicated that the RS had statistically significant prognostic value for patients with ILC. In addition, an absolute OS advantage was correlated with the receipt of chemotherapy by patients with ILC who had a high RS with N0 or N1 disease.

CONCLUSIONS

Patients with ILC who have a high RS are treated less often with chemotherapy compared with similar patients who have IDC. Nevertheless, the RS has a prognostic as well as a predictive value in ILC, with an association between OS benefit and chemotherapy receipt in patients who have ILC with a high RS, especially if they have N1 disease.

LAY SUMMARY

Invasive lobular carcinoma (ILC) is a subtype of breast cancer comprising about 15% of cases. The Oncotype recurrence score (RS) is a genetic test of breast tumors that helps predict which patients might benefit from chemotherapy. Some have doubted the relevance of the RS for patients with ILC. In this study, the authors show that the RS is relevant for patients who have ILC. The RS has the potential of predicting the risk of recurrence and identifying patients with ILC who might benefit from chemotherapy.

Atlas of Lobular Breast Cancer Models: Challenges and Strategic Directions

Invasive lobular carcinoma (ILC) accounts for up to 15% of all breast cancer (BC) cases and responds well to endocrine treatment when estrogen receptor α-positive (ER+) yet differs in many biological aspects from other ER+ BC subtypes. Up to 30% of patients with ILC will develop late-onset metastatic disease up to ten years after initial tumor diagnosis and may experience failure of systemic therapy. Unfortunately, preclinical models to study ILC progression and predict the efficacy of novel therapeutics are scarce. Here, we review the current advances in ILC modeling, including cell lines and organotypic models, genetically engineered mouse models, and patient-derived xenografts. We also underscore four critical challenges that can be addressed using ILC models: drug resistance, lobular tumor microenvironment, tumor dormancy, and metastasis. Finally, we highlight the advantages of shared experimental ILC resources and provide essential considerations from the perspective of the European Lobular Breast Cancer Consortium (ELBCC), which is devoted to better understanding and translating the molecular cues that underpin ILC to clinical diagnosis and intervention. This review will guide investigators who are considering the implementation of ILC models in their research programs.

[Breast cancer-related thrombotic microangiopathy: A review]

Thrombotic Microangiopathies (TM) have been described since the 1960s. They are characterized by presence of mechanical haemolytic anemia associated with peripheral thrombocytopenia. TM in cancer can be related to several causes, whose cancer himself: cancer-related microangiopathic haemolytic anaemia (MAHA). Incidence of cancer related MAHA remains unknown. Cancer-related MAHA are mainly observed in mucin-producer adenocarcinomas, such as gastric (half of reported cases) and breast cancer. We conducted a review of all original published cases of TM reported in breast cancer, and we specifically investigated BC-MAHA cases. A Medline search identified 158 MAHA cases including 118 BC-MAHA, and 40 drug-related MAHA. Most of BC-MAHA occur in disseminated cancers, mainly with medullar involvement, and/or bone metastasis. Patients typically suffer from poor general state, bone pain, and/or dyspnea. Laboratory abnormalities such as myelemia or erythromyelemia in peripheral blood are frequently observed. Incidence of coagulation disorders is increased, compared to other MAHA causes. BC-MAHA prognosis is dramatically poor. Treatments classically used in other MAHA causes, such as plasmapheresis or immunoglobulins, are inefficient. Urgent anti-neoplastic therapy may be the only effective treatment, associated to symptomatic therapies (transfusions, blood pressure control).

Association of antidiabetic medication and statins with survival from ductal and lobular breast carcinoma in women with type 2 diabetes

We investigated the survival of female patients with pre-existing type 2 diabetes (T2D) diagnosed with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) of breast, in relation to the use of metformin, other antidiabetic medication (ADM) and statins. The study cohort consisted of 3,165 women (2,604 with IDC and 561 with ILC). The cumulative mortality from breast cancer (BC) and from other causes was calculated using the Aalen-Johansen estimator. The cause-specific mortality rates were analysed by Cox models, and adjusted hazard ratios (HRs) were estimated for the use of different medications. No evidence of an association of metformin use with BC mortality was observed in either IDC (HR 0.92, 95% confidence interval [CI] 0.64-1.31) or ILC (HR 0.68, 95% CI 0.32-1.46) patients, when compared to other oral ADMs. The mortality from other causes was found to be lower amongst the IDC patients using metformin (HR 0.64, 95% CI 0.45-0.89), but amongst ILC patients the evidence was inconclusive (HR 1.22, 95% CI 0.64-2.32). Statin use was consistently associated with reduced mortality from BC in IDC patients (HR 0.77, 95% CI 0.62-0.96) and ILC patients (HR 0.59, 95% CI 0.37-0.96), and also mortality from other causes in IDC patients (HR 0.81, 95% CI 0.67-0.96) and in ILC patients (HR 0.66, 95% CI 0.43-1.01). We found no sufficient evidence for the possible effects of metformin and statins on the prognosis of BC being different in the two histological subtypes.

Understanding the function of the tumor microenvironment, and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer (BC), including metastasis, and drug resistance, is driven by multiple signaling pathways in the tumor microenvironment (TME), which hamper antitumor immunity. Recently, long non-coding RNAs have been reported to mediate pathophysiological develop-ments such as metastasis as well as immune suppression within the TME. Given the complex biology of BC, novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes. In this review, we describe the advances in the biology of breast neoplasia, including cellular and molecular biology, heterogeneity, and TME. We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC. Finally, we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms, crustaceans, and fishes and their synergistic effects in combination with other anticancer drugs. Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development, thus assisting current therapeutic regimens.

Intraductal xenografts show lobular carcinoma cells rely on their own extracellular matrix and LOXL1

Invasive lobular carcinoma (ILC) is the most frequent special histological subtype of breast cancer, typically characterized by loss of E-cadherin. It has clinical features distinct from other estrogen receptor-positive (ER+ ) breast cancers but the molecular mechanisms underlying its characteristic biology are poorly understood because we lack experimental models to study them. Here, we recapitulate the human disease, including its metastatic pattern, by grafting ILC-derived breast cancer cell lines, SUM-44 PE and MDA-MB-134-VI cells, into the mouse milk ducts. Using patient-derived intraductal xenografts from lobular and non-lobular ER+ HER2- tumors to compare global gene expression, we identify extracellular matrix modulation as a lobular carcinoma cell-intrinsic trait. Analysis of TCGA patient datasets shows matrisome signature is enriched in lobular carcinomas with overexpression of elastin, collagens, and the collagen modifying enzyme LOXL1. Treatment with the pan LOX inhibitor BAPN and silencing of LOXL1 expression decrease tumor growth, invasion, and metastasis by disrupting ECM structure resulting in decreased ER signaling. We conclude that LOXL1 inhibition is a promising therapeutic strategy for ILC.

Characteristics and outcome of breast cancer-related microangiopathic haemolytic anaemia: a multicentre study

BACKGROUND

Cancer-related microangiopathic haemolytic anaemia (MAHA) is a rare but life-threatening paraneoplastic syndrome. Only single cases or small series have been reported to date. We set up a retrospective multicentre study focusing on breast cancer-related MAHA.

METHODS

Main inclusion criteria were known diagnosis of breast cancer, presence of schistocytes and either low haptoglobin or cytopenia and absence of any causes of MAHA other than breast cancer, including gemcitabine- or bevacizumab-based treatment. Patient characteristics, treatments and outcome were retrieved from digital medical records.

RESULTS

Individual data from 54 patients with breast cancer-related MAHA were obtained from 7 centres. Twenty-three (44%) patients had a breast tumour with lobular features, and most primary tumours were low grade (grade I/II, N = 39, 75%). ER+/HER2-, HER2+ and triple-negative phenotypes accounted for N = 33 (69%), N = 7 (15%) and N = 8 (17%) cases, respectively. All patients had stage IV cancer at the time of MAHA diagnosis. Median overall survival (OS) was 28 days (range 0-1035; Q1:10, Q3:186). Independent prognostic factors for early death (≤ 28 days) were PS > 2 (OR = 7.0 [1.6; 31.8]), elevated bilirubin (OR = 6.9 [1.1; 42.6]), haemoglobin < 8.0 g/dL (OR = 3.7 [0.9; 16.7]) and prothrombin time < 50% (OR = 9.1 [1.2; 50.0]). A score to predict early death displayed a sensitivity of 86% (95% CI [0.67; 0.96]), a specificity of 73% (95% CI [0.52; 0.88]) and an area under the curve of 0.90 (95% CI [0.83; 0.97]).

CONCLUSIONS

Breast cancer-related MAHA appears to be a new feature of invasive lobular breast carcinoma. Prognostic factors and scores may guide clinical decision-making in this serious but not always fatal condition.

Comparison of Overall Survival Between Invasive Lobular Breast Carcinoma and Invasive Ductal Breast Carcinoma: A Propensity Score Matching Study Based on SEER Database

Objective

Invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) account for most breast cancers. However, the overall survival (OS) differences between ILC and IDC remain controversial. This study aimed to compare nonmetastatic ILC to IDC in terms of survival and prognostic factors for ILC.

Methods

This retrospective cohort study used data from the Surveillance, Epidemiology and End Results (SEER) Cancer Database (www.seer.cancer.gov). Women diagnosed with nonmetastatic ILC and IDC between 2006 and 2016 were included. A propensity score matching (PSM) method was used in our analysis to reduce baseline differences in clinicopathological characteristics and survival outcomes. Kaplan-Meier curves and log-rank test were used for survival analysis.

Results

Compared to IDC patients, ILC patients were diagnosed later in life with poorly differentiated and larger lesions, as well as increased expression of estrogen receptors (ERs) and/or progesterone receptors (PRs). A lower rate of radiation therapy and chemotherapy was observed in ILC. After PSM, ILC, and IDC patients exhibited similar OS (HR=1.017, p=0.409, 95% CI: 0.967–1.069). In subgroup analysis of HR-negative, AJCC stage III, N2/N3 stage patients, or those who received radiotherapy, ILC patients exhibited worse OS compared to IDC patients. Furthermore, multivariate analysis revealed a 47% survival benefit for IDC compared to ILC in HR-negative patients who received chemotherapy (HR=1.47, p=0.01, 95% CI: 1.09–1.97).

Conclusions

Our results demonstrated that ILC and IDC patients had similar OS after PSM. However, ILC patients with high risk indicators had worse OS compared to IDC patients by subgroup analysis.

Tumor-infiltrating lymphocytes are associated with poor prognosis in invasive lobular breast carcinoma

The prognostic impact of tumor-infiltrating lymphocytes (TILs) within invasive lobular carcinoma (ILC) remains to be better characterized. In estrogen receptor (ER)-negative invasive ductal carcinomas of no special type (IDC-NST), TILs are associated with good prognosis. The aim of this study was to examine TILs in ILC, with particular focus on prognostic and clinicopathologic features. A cohort comprising 459 consecutive ILCs diagnosed in a single institution from 2005 to 2008 met the eligibility criteria for this study. The percentage of tumor area occupied by TILs was quantified by two breast pathologists and categorized into three groups: no TILs, ≤5%, >5%. Clinicopathologic features were tested by Fisher's exact tests or Chi² tests. Overall survival (OS) and invasive disease-free survival (iDFS) were estimated by Kaplan-Meier and Cox proportional hazard statistics. There were 239 TIL-negative cases, 185 cases with ≤5% TILs, and 35 cases with >5% TILs. TILs were associated with younger age, larger tumors, lymph node involvement, poor Nottingham prognostic index, HER2 amplification, multinucleation, and prominent nucleoli (p < 0.05). Poor OS was significantly associated with increasing TILs in the univariate Cox proportional hazards model (p < 0.001) and Kaplan-Meier estimator (p < 0.05, log-rank test). Similar results were observed for iDFS (p = 0.004 for Cox univariate and p = 0.005 for log-rank test). Notably, TILs can identify a subset of ILC patients with poor OS independently of molecular subtype and lymph node metastases (multivariate Cox, p < 0.001, OS hazard ratio (HR) = 4.38 and HR = 6.15, for ≤5% and >5% TILs, respectively, vs. absence of TILs). Prominent nucleoli was the only nuclear feature associated with poor OS (p = 0.05) and iDFS (p = 0.05) in univariate Cox survival analysis. TILs represent a promising new morphologic biomarker associated with poor outcome of ILC, in contrast with that observed in ER-negative IDC-NST.

A nomogram for determining the disease-specific survival in invasive lobular carcinoma of the breast: A population study

We aimed to establish and validate a nomogram for predicting the disease-specific survival of invasive lobular carcinoma (ILC) patients.The Surveillance, Epidemiology, and End Results program database was used to identify ILC from 2010 to 2015, in which the data was extracted from 18 registries in the US. Multivariate Cox regression analysis was performed to identify independent prognostic factors and a nomogram was constructed to predict the 3-year and 5-year survival rates of ILC patients based on Cox regression. Predictive values were compared between the new model and the American Joint Committee on Cancer staging system using the concordance index, calibration plots, integrated discrimination improvement, net reclassification improvement, and decision-curve analyses.In total, 4155 patients were identified. After multivariate Cox regression analysis, nomogram was established based on a new model containing the predictive variables of age, the primary tumor site, histology grade, American Joint Committee on Cancer TNM (tumor node metastasis) stages II, III, and IV, breast cancer subtype, therapy modality (surgery and chemotherapy). The concordance index for the training and validation cohorts were higher for the new model (0.781 and 0.832, respectively) than for the old model (0.733 and 0.779). The new model had good performance in the calibration plots. Net reclassification improvement and integrated discrimination improvement were also improved. Finally, decision-curve analyses demonstrated that the nomogram was clinically useful.We have developed a reliable nomogram for determining the prognosis and treatment outcomes of ILC. The new model facilitates the choosing of superior medical examinations and the optimizing of therapeutic regimens with cooperation among oncologists.

Characterization of circulating breast cancer cells with tumorigenic and metastatic capacity

Functional studies giving insight into the biology of circulating tumor cells (CTCs) remain scarce due to the low frequency of CTCs and lack of appropriate models. Here, we describe the characterization of a novel CTC‐derived breast cancer cell line, designated CTC‐ITB‐01, established from a patient with metastatic estrogen receptor‐positive (ER⁺) breast cancer, resistant to endocrine therapy. CTC‐ITB‐01 remained ER⁺ in culture, and copy number alteration (CNA) profiling showed high concordance between CTC‐ITB‐01 and CTCs originally present in the patient with cancer at the time point of blood draw. RNA‐sequencing data indicate that CTC‐ITB‐01 has a predominantly epithelial expression signature. Primary tumor and metastasis formation in an intraductal PDX mouse model mirrored the clinical progression of ER⁺ breast cancer. Downstream ER signaling was constitutively active in CTC‐ITB‐01 independent of ligand availability, and the CDK4/6 inhibitor Palbociclib strongly inhibited CTC‐ITB‐01 growth. Thus, we established a functional model that opens a new avenue to study CTC biology.

Multigene testing in breast cancer: What have we learned from the 21-gene recurrence score assay?

Most invasive breast cancers express hormone receptors (HR) and typically have a favorable prognosis following endocrine therapy. Patients at a higher risk of recurrence can be identified by multigene prognostic classifiers such as the 21-gene recurrence score (RS) assay, 70-gene prognostic signature, PAM-50, 12-gene molecular score, and others. The 21-gene RS assay (Oncotype Dx™, Genomic Health, Redwood City, CA) has level I clinical evidence and is the most widely used multigene assay in North America. The RS assay is based on reverse transcriptase polymerase chain reaction that can be performed on the RNA isolated from formalin-fixed paraffin-embedded tissue. It evaluates the expression of 16 cancer-related genes developed based on a multi-step approach. Due to its ability to assess recurrence risk and predict potential benefit from chemotherapy, the assay is recommended for patients with node-negative, HR-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer by the American Society of Clinical Oncology, National Comprehensive Cancer Network clinical practice guidelines in oncology, European Society for Medical Oncology clinical practice guidelines, and St. Gallen consensus panel guidelines. The RS assay has also been incorporated in the prognostic stage groups in the 8th edition of the American Joint Commission of Cancer staging manual in order to provide essential genomic information for optimal treatment decisions. This review will focus on the utility of the RS assay in HR-positive and HER2-negative breast cancer patients, including risk of distant and locoregional recurrence in node-negative and node-positive tumors, association with radiotherapy, special subtypes of breast cancer, practical issues related to selecting tumors for testing, and overview of the recently published TailorX (Trial Assigning IndividuaLized Options for treatment [Rx]) results.

Adjuvant chemotherapy could not bring survival benefit to HR-positive, HER2-negative, pT1b-c/N0-1/M0 invasive lobular carcinoma of the breast: a propensity score matching study based on SEER database

BACKGROUND

The benefit of adjuvant chemotherapy in invasive lobular carcinoma (ILC) is still unclear. The objective of the current study was to elucidate the effectiveness of adjuvant chemotherapy in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, pT1b-c/N0-1/M0 ILC.

METHODS

Based on Surveillance, Epidemiology, and End-Results (SEER) database, we identified original 12,334 HR-positive, HER2-negative, pT1b-c/N0-1/M0 ILC patients, who were then divided into adjuvant chemotherapy group and control group. End-points were overall survival (OS) and breast cancer-specific mortality (BCSM). Aiming to minimize the selection bias of baseline characteristics, Propensity Score Matching (PSM) method was used.

RESULTS

In a total of 12,334 patients with HR-positive, HER2-negative, pT1b-c/N0-1/M0 ILC, 1785 patients (14.5%) were allocated into adjuvant chemotherapy group and 10,549 (85.5%) into control group. Used PSM, the 1785 patients in adjuvant chemotherapy group matched to the 1785 patients in control group. By Kaplan-Meier survival analyses, we observed no beneficial effect of adjuvant chemotherapy on OS in both original samples (P = 0.639) and matched samples (P = 0.962), however, ineffective or even contrary results of adjuvant chemotherapy on BCSM both in original samples (P = 0.001) and in matched samples (P = 0.002). In both original and matched multivariate Cox models, we observed ineffectiveness of adjuvant chemotherapy on OS (hazard ratio (HR) for overall survival = 0.82, 95% confidence interval (CI) [0.62-1.09]; P = 0.172 and HR = 0.90, 95%CI [0.65-1.26]; P = 0.553, respectively), unexpectedly promoting effect of adjuvant chemotherapy on BCSM (HR = 2.33, 95%CI [1.47-3.67]; P = 0.001 and HR = 2.41, 95%CI [1.32-4.39]; P = 0.004, respectively). Standard surgery was beneficial to the survival of patients. Lymph node metastasis was detrimental to survival and radiotherapy brought survival benefit in original samples, but two issues had unobvious effect in matched samples.

CONCLUSION

In this study, adjuvant chemotherapy did not improve survival for patients with HR-positive, HER2-negative pT1b-c/N0-1/M0 ILC.

18F-fluorodeoxyglucose PET/computed tomography in locoregional staging and assessment of biological and clinical aggressiveness of breast cancer subtypes

OBJECTIVE

We aimed to evaluate the availability of fluorine-18-fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in initial axillary lymph node (ALN) staging in breast cancer. The secondary objective is to evaluate the role of FDG PET/CT as a pretest in sentinel lymph node biopsy vs. axillary lymph node dissection when predicting disease aggressiveness.

METHODS

The study evaluated retrospectively 194 breast cancer patients who underwent preoperative 18F-FDG. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FDG PET/CT for ALN metastases were confirmed with histopathology as the gold standard.

RESULTS

The value of the area under curve (AUC), sensitivity and specificity for ALN metastases were determined as 0.847, 78.8% and 92.6%, respectively. The cut-off value of the maximum standardized uptake value (SUVmax) for metastatic ALN detection was calculated as 1.79. PPV, NPV and the accuracy of 18F-FDG PET/CT were 0.933 (93.3%), 0.75 (75%) and 0.837 (83.7%), respectively. The SUVmax value of the primary lesion was significantly correlated with grade, estrogen receptor (ER) status, progesterone receptor (PR) status, SUVmax value of metastatic ALN, Her-2 status and Ki-67 level. Molecular subtypes revealed no statistically significant difference in terms of mean SUVmax value.

CONCLUSION

High values of AUC, sensitivity, specificity, NPV and PPV encourage utilization of PET/CT for locoregional staging of nonmetastatic breast carcinoma. The significant correlation between the primary tumor SUVmax value and grade, ER status, PR status and Ki-67 level increases the prognostic predictive value of the preoperative PET/CT.

Combination of targeted daunorubicin liposomes and targeted emodin liposomes for treatment of invasive breast cancer

Conventional treatment fails to completely eliminate highly invasive breast cancer cells, and most surviving breast cancer cells tend to reproliferate and metastasize by forming vasculogenic mimicry (VM) channels. Thus, a type of targeted liposomes was developed by modification with arginine₈-glycine-aspartic acid (R₈GD) to encapsulate daunorubicin and emodin separately. A combination of the two targeted liposomes was then developed to destroy VM channels and inhibit tumour metastasis. MDA-MB-435S cells, a highly invasive breast cancer, were then evaluated in vitro and in mice. The experiments indicated that R₈GD modified daunorubicin liposomes plus R₈GD modified emodin liposomes had small particle size, uniform particle size distribution and high drug encapsulation rate. The combination of the two targeted liposomes exerted strong toxicity on the MDA-MB-435S cells and effectively inhibited the formation of VM channels and the metastasis of tumour cells. Action mechanism studies showed that the R₈GD modified daunorubicin liposomes plus R₈GD modified emodin liposomes could downregulate some metastasis-related proteins, including MMP-2, VE-cad, TGF-β1 and HIF-1α. These studies also demonstrated that the targeted liposomes allowed the chemotherapeutic drug to selectively accumulate at tumour site, thus exhibiting a distinct antitumor effect. Therefore, the combination of targeted daunorubicin liposomes and targeted emodin liposomes can provide a potential treatment for invasive breast cancer.

Overexpression of UHRF1 and its potential role in the development of invasive ductal breast cancer validated by integrative bioinformatics and immunohistochemistry analyses

BACKGROUND

Increasing evidence has highlighted the role of ubiquitin-like PHD and RING finger domain-containing protein 1 (UHRF1) in the development of cancers, including hepatocellular carcinoma, pancreatic cancer, and bladder cancer. However, the correlation between UHRF1 and breast cancer remains unclear. The present study aimed to analyze the expression of UHRF1 and its role in the development of invasive ductal breast cancer (IDC) by integrating multilevel expression data and immunohistochemistry analysis.

METHODS

The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases were used to gather UHRF1 expression data on IDC. Additionally, immunohistochemistry analysis was used to investigate the correlations between UHRF1 expression and the clinical characteristics of IDC.

RESULTS

The GEO and TCGA databases indicated that UHRF1 was up-regulated in IDC. Consistently, the immunohistochemical specimens showed that the significant overexpression of UHRF1 in IDC, and its expression level showed an increasing trend from ductal carcinomas in situ to IDC. Notably, the increased levels of UHRF1 were closely correlated with estrogen receptor expression, pathological grade, and the prognosis of the disease. In addition, patients with a high UHRF1 expression had a poorer prognosis.

CONCLUSIONS

In conclusion, our findings suggested that UHRF1 plays a promoting role in breast tumorigenesis, and the over-expression of UHRF1 could serve as a biomarker for the prognosis in invasive ductal carcinomas in breast cancer.

Immune Infiltration in Invasive Lobular Breast Cancer

Background

Invasive lobular breast cancer (ILC) is the second most common histological subtype of breast cancer after invasive ductal cancer (IDC). Here, we aimed at evaluating the prevalence, levels, and composition of tumor-infiltrating lymphocytes (TILs) and their association with clinico-pathological and outcome variables in ILC, and to compare them with IDC.

Methods

We considered two patient series with TIL data: a multicentric retrospective series (n = 614) and the BIG 02-98 study (n = 149 ILC and 807 IDC). We compared immune subsets identified by immuno-histochemistry in the ILC (n = 159) and IDC (n = 468) patients from the Nottingham series, as well as the CIBERSORT immune profiling of the ILC (n = 98) and IDC (n = 388) METABRIC and The Cancer Genome Atlas patients. All ILC/IDC comparisons were done in estrogen receptor (ER)–positive/human epidermal growth factor receptor 2 (HER2)–negative tumors. All statistical tests were two-sided.

Results

TIL levels were statistically significantly lower in ILC compared with IDC (fold-change = 0.79, 95% confidence interval = 0.70 to 0.88, P < .001). In ILC, high TIL levels were associated with young age, lymph node involvement, and high proliferative tumors. In the univariate analysis, high TIL levels were associated with worse prognosis in the retrospective and BIG 02-98 lobular series, although they did not reach statistical significance in the latter. The Nottingham series revealed that the levels of intratumoral but not total CD8⁺ were statistically significantly lower in ILC compared with IDC. Comparison of the CIBERSORT profiles highlighted statistically significant differences in terms of immune composition.

Conclusions

This study shows differences between the immune infiltrates of ER-positive/HER2-negative ILC and IDC in terms of prevalence, levels, localization, composition, and clinical associations.

Impact of invasive lobular carcinoma on long-term outcomes in Mexican breast cancer patients

PURPOSE

The aim of this study was to compare the difference in disease-free survival (DFS) and overall survival (OS) between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) in our Hispanic population with breast cancer (BC).

METHODS

We retrospectively analyzed a database of 4533 non-metastatic BC patients treated for BC at the National Cancer Institute in Mexico (INCan) between 2006 and 2016. We compared clinical characteristics, treatment and survival between women with invasive ductal and invasive lobular BC. We evaluated differences between survival curves with the log-rank test and used Cox's proportional hazards model for the multivariate analysis.

RESULTS

Median follow-up time was 42.13 months (IQ₂₅ 25.2-IQ₇₅ 72.06). The median age was 50.9 years (IQ₂₅ 43.5-IQ₇₅ 59.8). DFS at 5 years was 80.8% for IDC versus 76.2% for ILC. 5 years OS was 88.7% for IDC versus 84.3% for ILC. Multivariate analysis showed that factors that negatively affected the 5-year DFS include: clinical stage III [hazard ratio (HR) 4.2, 95% CI 3.36-5.35; p < 0.001], triple negative phenotype (HR 1.4, 95% CI 1.08-1.81; p = 0.009), Ki67 ≥ 18 (HR 1.6, 95% CI 1.28-2.11; p < 0.001), and lobular histological type (HR 1.6, 95% CI 1.09-2.49; p = 0.017). Factors associated with a negative impact on OS were: clinical stage III (HR 4.5, 95% CI 3.15-6.54; p < 0.001), triple negative phenotype (HR 2.4, 95% CI 1.69-3.48; p < 0.001), and Ki67 ≥ 18% (HR 1.9, 95% CI 1.27-2.92; p = 0.02).

CONCLUSION

Our results highlight the different biology of ILC and show that long-term prognosis in terms of DFS is not as favorable as previously reported.

ESR1 mutations in metastatic lobular breast cancer patients

Invasive lobular breast cancer (ILC) represents the second most common histology of breast cancer after invasive ductal breast cancer (IDC), accounts for up to 15% of all invasive cases and generally express the estrogen receptor (ER, coded by the ESR1 gene). ESR1 mutations have been associated with resistance to endocrine therapy, however these have not been specifically evaluated in ILC. We assessed the frequency of ESR1 mutations by droplet digital PCR in a retrospective multi-centric series of matched primary tumor and recurrence samples (n = 279) from 80 metastatic ER-positive ILC patients. We further compared ESR1 mutations between IDC and ILC patients in metastatic samples from MSKCC-IMPACT (n = 595 IDC and 116 ILC) and in ctDNA from the SoFEA and PALOMA-3 trials (n = 416 IDC and 76 ILC). In the retrospective series, the metastases from seven patients (9%) harbored ESR1 mutations, which were absent from the interrogated primary samples. Five patients (6%) had a mutation in the primary tumor or axillary metastasis, which could not be detected in the matched distant metastasis. In the MSKCC-IMPACT cohort, as well as in the SoFEA and PALOMA-3 trials, there were no differences in prevalence and distribution of the mutations between IDC and ILC, with D538G being the most frequent mutation in both histological subtypes. To conclude, no patient had an identical ESR1 mutation in the early and metastatic disease in the retrospective ILC series. In the external series, there was no difference in terms of prevalence and type of ESR1 mutations between ILC and IDC.

Among a cohort of 80 women with metastatic lobular breast cancer, no patient had an identical mutation in the ESR1 gene in both metastases and localized tumors. ESR1 encodes the estrogen receptor targeted by endocrine therapy — thus, tumors harboring mutations in this gene may require different treatment strategies. Christine Desmedt
 from KU Leuven, Belgium, and colleagues found that 9% of patients had metastases with ESR1 mutations that were absent in primary breast tumors; another 6% had mutations in the primary tumors or in cancer-invaded lymph nodes that were not detected in distant metastatic sites. Comparisons with other datasets showed that the prevalence and distribution of ESR1 mutations were not significantly different among women with lobular and ductal breast cancer, the two most common subtypes of the disease.

Integrated landscape of copy number variation and RNA expression associated with nodal metastasis in invasive ductal breast carcinoma

Background

Lymph node metastasis (NM) in breast cancer is a clinical predictor of patient outcomes, but how its genetic underpinnings contribute to aggressive phenotypes is unclear. Our objective was to create the first landscape analysis of CNV-associated NM in ductal breast cancer. To assess the role of copy number variations (CNVs) in NM, we compared CNVs and/or associated mRNA expression in primary tumors of patients with NM to those without metastasis.

Results

We found CNV loss in chromosomes 1, 3, 9, 18, and 19 and gains in chromosomes 5, 8, 12, 14, 16-17, and 20 that were associated with NM and replicated in both databases. In primary tumors, per-gene CNVs associated with NM were ten times more frequent than mRNA expression; however, there were few CNV-driven changes in mRNA expression that differed by nodal status. Overlapping regions of CNV changes and mRNA expression were evident for the CTAGE5 gene. In 8q12, 11q13-14, 20q1, and 17q14-24 regions, there were gene-specific gains in CNV-driven mRNA expression associated with NM.

Methods

Data on CNV and mRNA expression from the TCGA and the METABRIC consortium of breast ductal carcinoma were utilized to identify CNV-based features associated with NM. Within each dataset, associations were compared across omic platforms to identify CNV-driven variations in gene expression. Only replications across both datasets were considered as determinants of NM.

Conclusions

Gains in CTAGE5, NDUFC2, EIF4EBP1, and PSCA genes and their expression may aid in early diagnosis of metastatic breast carcinoma and have potential as therapeutic targets.

Breast Cancers of Special Histologic Subtypes Are Biologically Diverse

BACKGROUND/OBJECTIVE

Cancers classified as "special histologic subtypes" are felt to have a good prognosis. We used the 21-gene Oncotype DX Breast Recurrence Score^® multigene assay to examine prognostic variation within special histologic subtypes. We also examined the Recurrence Score^® (RS) distribution among the more common ductal (IDC) and lobular (ILC) cancers.

METHODS

610,350 tumor specimens examined in the Genomic Health clinical laboratory from 2/2004 to 8/2017 were included. Specimen histology was classified centrally using a single H&E slide and World Health Organization criteria. RS distribution (low < 18, intermediate 18-30, and high ≥ 31) was compared among histologic subtypes.

RESULTS

Median patient age was 60 years (IQR 51-67); 80% were node negative. Most patients had low RS results (59.2%); only 9.5% had high results. The lowest mean RS was seen in the papillary subtype (11); the highest in the IDC group (18.4). Mean RS for all special subtypes was lower than that of IDC patients. When the high RS threshold was decreased from 31 to 25, as used in the TAILORx and RxPONDER trials, the number of high RS-result patients increased from 9.5% to 16.8%. Patients with ILC had a lower mean RS result than patients with IDC, 16.5 versus 18.4.

CONCLUSION

There is substantial diversity in predicted prognosis among patients with cancers classified as special histologic subtypes, with 12-25% having intermediate RS results and 0.5-9% having high RS results. Pending further definition of the role of chemotherapy for patients with intermediate RS results by TAILORx and RxPONDER, the RS result may help to inform systemic therapy decisions in these patients.

Molecular Classification of Breast Cancer

Breast cancer is a heterogeneous disease, observed traditionally by morphology and protein expression but, more recently with the advent of modern molecular technologies, at the genomic and transcriptomic level. This review describes the association between the different molecular subtypes with the histologic subtypes of breast cancer alongside some of their major genomic characteristics and illustrates how these subtypes may affect the appearance of tumors on imaging studies. The authors aim to show how molecular stratification can be used to augment traditional methods to improve our understanding of breast cancers and their clinical management.

ERBB2 mutation is associated with a worse prognosis in patients with CDH1 altered invasive lobular cancer of the breast

E-cadherin (CDH1) is a glycoprotein that mediates adhesion between epithelial cells and also suppresses cancer invasion. Mutation or deletion of the CDH1 gene has been reported in 30-60% cases of invasive lobular carcinoma (ILC). However, little is known about genomic differences between ILC with and without a CDH1 alteration. Therefore, we analyzed whole genome sequencing data of 169 ILC cases from The Cancer Genome Atlas (TCGA) to address this deficiency. Our study shows that CDH1 gene was altered in 59.2% (100/169) of ILC. No significant difference was identified between CDH1-altered and -unaltered ILC cases for any of the examined demographic, clinical or pathologic characteristics, including histologic grade, tumor stage, lymph node metastases, or ER/PR/HER2 states. Seven recurrent mutations (PTEN, MUC16, ERBB2, FAT4, PCDHGA2, HERC1 and FLNC) and four chromosomal changes with recurrent copy number variation (CNV) (11q13, 17q12-21, 8p11 and 8q11) were found in ILC, which correlated with a positive or negative CDH1 alteration status, respectively. The prevalence of the most common breast cancer driver abnormalities including TP53 and PIK3CA mutations and MYC and ERBB2 amplifications showed no difference between the two groups. However, CDH1-altered ILC with an ERBB2 mutation shows a significantly worse prognosis compared to its counterparts without such a mutation. Our study suggests that CDH1-altered ILC patients with ERBB2 mutations may represent an actionable group of patients who could benefit from targeted breast cancer therapy.

Invasive lobular carcinoma of the breast: A special histological type compared with invasive ductal carcinoma

The clinical outcomes and therapeutic strategies for infiltrating ductal carcinoma (IDC) and infiltrating lobular carcinoma (ILC) are not uniform. The primary objectives of this study were to identify the differences in the clinical characteristics and prognoses between ILC and IDC, and identify the high-risk population based on the hormone receptor status and metastasis sites. The Surveillance, Epidemiology, and End Results Program database was searched and patients diagnosed with ILC or IDC from 1990 to 2013 were identified. In total,796,335 patients were analyzed, including 85,048 withILC (10.7%) and 711,287 withIDC (89.3%). The ILC group was correlatedwith older age, larger tumor size, later stage, lower grade, metastasis disease(M1) disease, and greater counts ofpositive lymph nodesandestrogen-receptor-positive (ER)/progesterone receptor-positive (PR) positive nodes. The overall survival showed an early advantage for ILC but a worse outcome after 5 years. Regarding the disease-specific survival, the IDC cohort had advantages over the ILC group, both during the early years and long-term. In hormone status and metastasis site subgroup analyses, the ER+/PR+ subgroup had the best survival, while the ER+/PR- subgroup had the worst outcome, especially the ILC cohort. ILC and IDC had different metastasis patterns. The proportion of bone metastasis was higher in the ILC group (91.52%) than that in the IDC (76.04%), and the ILC group was more likely to have multiple metastasis sites. Survival analyses showed patients with ILC had a higher risk of liver metastasis (disease-specific survival[DSS]; P = 0.046), but had a better overall survival than the bone metastasis group (P<0.0001). We concluded that the long-term prognosis for ILC was poorer than that for IDC, and the ER+/PR- subgroup had the worst outcome. Therefore, the metastasis pattern and prognosis must be seriously evaluated, and a combination of endocrine therapy and chemotherapy should be considered.

Distinct Pattern of Metastases in Patients with Invasive Lobular Carcinoma of the Breast

BACKGROUND

Invasive lobular carcinoma (ILC) comprises around 10 - 15% of invasive breast cancers. Few prior studies have demonstrated a unique pattern of metastases between ILC and the more common invasive ductal carcinoma (IDC). To our knowledge, such data is limited to first sites of distant recurrence. We aimed to perform a comparison of the metastatic pattern of ILC and IDC at first distant recurrence as well as over the entire course of metastatic disease.

METHODS

We used a prospectively collated database of patients with metastatic breast cancer. Breast cancer recurrence or metastases were classified into various sites and a descriptive analysis was performed.

RESULTS

Among 761 patients, 88 (11.6%) were diagnosed with ILC and 673 (88.4%) with IDC. Patients with ILC showed more frequent metastases to the bone (56.8 vs. 37.7%, p = 0.001) and gastrointestinal (GI) tract (5.7 vs. 0.3%, p < 0.001) as first site of distant recurrence, and less to organs such as lung (5.7 vs. 24.2%, p < 0.001) and liver (4.6 vs. 11.4%, p = 0.049). Over the entire course of metastatic disease, more patients with ILC had ovarian (5.7 vs. 2.1%, p = 0.042) and GI tract metastases (8.0 vs. 0.6%, p < 0.001), also demonstrating reduced tendency to metastasize to the liver (20.5 vs. 49.0%, p < 0.001) and lung (23.9 vs. 51.9%, p < 0.001). All associations but bone held after sensitivity analysis on hormonal status. Although patients presenting with ILC were noted to have more advanced stage at presentation, recurrence-free survival in these patients was increased (4.8 years vs. 3.2 years, p = 0.017). However, overall survival was not (2.5 vs. 2.0 years, p = 0.75).

CONCLUSION

After accounting for hormone receptor status, patients with IDC had greater lung/pleura and liver involvement, while patients with ILC had a greater propensity to develop ovarian and GI metastases both at first site and overall. Clinicians can use this information to provide more directed screening for metastases; it also adds to the argument that these two variants of breast cancer should be managed as unique diseases.

The 21-gene recurrence score in special histologic subtypes of breast cancer with favorable prognosis

BACKGROUND/PURPOSE

The 21-gene recurrence score (RS) assay predicts the likelihood of distant recurrence and chemotherapy benefit in early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. Data on the RS of special histologic subtypes of invasive breast carcinoma with favorable prognosis are limited.

METHODS

We reviewed our institutional database to identify patients with special histologic subtypes of breast cancer associated with favorable prognosis and available RS results. Our cohort consists of fifty-seven women: thirty-three patients with pure mucinous carcinoma (MC), ten with tubular carcinoma (TC), nine with encapsulated papillary carcinoma (EPC), and five with solid papillary carcinoma (SPC).

RESULTS

Most (44/57, 77.2%) carcinomas had low RS (≤17), and none had high RS (≥31). All EPCs had low RS, but other subtypes had RS 18-30. Higher RS was associated with lower progesterone receptor (PR) expression by immunohistochemistry and lower PR mRNA scores (P ≤ 0.007). No morphologic feature (tumor grade, biopsy site changes, cellular stroma, inflammatory cells) was associated with RS ≥ 18. At a median follow-up of 40 months, the distant recurrence-free survival was 100%. One patient with SPC developed locoregional recurrence at 22 months.

CONCLUSIONS

As the largest series to date, our study raises the question of whether the RS assay is necessary for breast cancers with favorable histology. Reflex testing of node-negative, ER+/HER2- breast cancers may be deferred for these special histologic subtypes, emphasizing the need for multidisciplinary discussions between breast pathologists and other members of the breast cancer team.

MetaDCN: meta-analysis framework for differential co-expression network detection with an application in breast cancer

MOTIVATION

Gene co-expression network analysis from transcriptomic studies can elucidate gene-gene interactions and regulatory mechanisms. Differential co-expression analysis helps further detect alterations of regulatory activities in case/control comparison. Co-expression networks estimated from single transcriptomic study is often unstable and not generalizable due to cohort bias and limited sample size. With the rapid accumulation of publicly available transcriptomic studies, co-expression analysis combining multiple transcriptomic studies can provide more accurate and robust results.

RESULTS

In this paper, we propose a meta-analytic framework for detecting differentially co-expressed networks (MetaDCN). Differentially co-expressed seed modules are first detected by optimizing an energy function via simulated annealing. Basic modules sharing common pathways are merged into pathway-centric supermodules and a Cytoscape plug-in (MetaDCNExplorer) is developed to visualize and explore the findings. We applied MetaDCN to two breast cancer applications: ER+/ER- comparison using five training and three testing studies, and ILC/IDC comparison with two training and two testing studies. We identified 20 and 4 supermodules for ER+/ER- and ILC/IDC comparisons, respectively. Ranking atop are 'immune response pathway' and 'complement cascades pathway' for ER comparison, and 'extracellular matrix pathway' for ILC/IDC comparison. Without the need for prior information, the results from MetaDCN confirm existing as well as discover novel disease mechanisms in a systems manner.

AVAILABILITY AND IMPLEMENTATION

R package 'MetaDCN' and Cytoscape App 'MetaDCNExplorer' are available at http://tsenglab.biostat.pitt.edu/software.htm .

CONTACT

ctseng@pitt.edu.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Transcriptomic and genomic features of invasive lobular breast cancer

Accounting for 10-15% of all breast neoplasms, invasive lobular breast cancer (ILC) is the second most common histological subtype of breast cancer after invasive ductal breast cancer (IDC). Understanding ILC biology, which differs from IDC in terms of clinical presentation, treatment response, relapse timing and patterns, is essential in order to adopt novel, disease-specific management strategies. While the contribution of the histological subtypes to tumour biology has been poorly investigated and acknowledged in the past, recently several major, independent efforts have led to the assembly and molecular characterization of well-annotated ILC case sets. In this review, we provide a critical overview of the literature exploring ILC, through comprehensive and multiomic methods. The first part specifically focuses on ILC transcriptomic features by reviewing the intrinsic molecular subtypes, the application of gene expression scores for the prediction of recurrence, and the identification of gene expression subtypes. The second part describes the main research efforts that lead to the identification of the genomic landscape of ILC, with a special focus to findings that differentiate ILC from IDC and carry potential clinical relevance.

Estrogen and progesterone receptor expression levels do not differ between lobular and ductal carcinoma in patients with hormone receptor-positive tumors

Background

Differences in estrogen (ER) and progesterone (PR) expression between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) could be an underlying reason for the difference in chemo-sensitivity and response to hormonal therapy between ILC and IDC. The aim of this study was to investigate the differences in ER and PR expression levels between postmenopausal patients with hormonal receptor-positive ILC and IDC.

Methods

We included all ER and/or PR receptor-positive ILC and IDC, diagnosed between January 2011 and December 2013 from the population-based Netherlands Cancer Registry. A semi-quantitative classification was used to analyze differences in ER/PR expression, which consisted of three ER expression classes: 10–69, 70–89, and ≥90%. Differences in ER and PR expression levels between IDC and ILC were analyzed according to age group, tumor size, axillary nodal status, grade, and HER2 status.

Results

In total, 26,339 ER and/or PR-positive breast cancers were included in the study, of which 17% were ILC and 83% IDC. In patients with IDC, 86% of the tumors showed an ER expression level of 90% or more, compared to 84% in those with ILC. In both IDC and ILC a PR expression level of 90% or more was observed in 54% of the tumors. In postmenopausal patients aged 50–69 years no significant differences could be observed in ER and PR expression levels between ILC and IDC.

Conclusion

Patients with ER and PR-positive ILC and IDC have similar quantitative ER and PR expression profiles, implicating that ER/PR expression is unlikely to be a confounding factor in studies concerning chemo-sensitivity of ILC and IDC.

Prognostic Value of MammaPrint® in Invasive Lobular Breast Cancer

BACKGROUND

MammaPrint® is a microarray-based gene expression test cleared by the US Food and Drug Administration to assess recurrence risk in early-stage breast cancer, aimed to guide physicians in making neoadjuvant and adjuvant treatment decisions. The increase in the incidence of invasive lobular carcinomas (ILCs) over the past decades and the modest representation of ILC in the MammaPrint development data set calls for a stratified survival analysis dedicated to this specific subgroup.

STUDY AIM

The current study aimed to validate the prognostic value of the MammaPrint test for breast cancer patients with early-stage ILCs.

MATERIALS AND METHODS

Univariate and multivariate survival associations for overall survival (OS), distant metastasis-free interval (DMFI), and distant metastasis-free survival (DMFS) were studied in a study population of 217 early-stage ILC breast cancer patients from five different clinical studies.

RESULTS AND DISCUSSION

A significant association between MammaPrint High Risk and poor clinical outcome was shown for OS, DMFI, and DMFS. A subanalysis was performed on the lymph node-negative study population. In the lymph node-negative study population, we report an up to 11 times higher change in the diagnosis of an event in the MammaPrint High Risk group. For DMFI, the reported hazard ratio is 11.1 (95% confidence interval = 2.3-53.0).

CONCLUSION

Study results validate MammaPrint as an independent factor for breast cancer patients with early-stage invasive lobular breast cancer. Hazard ratios up to 11 in multivariate analyses emphasize the independent value of MammaPrint, specifically in lymph node-negative ILC breast cancers.

Efficacy and safety of palbociclib in combination with letrozole as first-line treatment of ER-positive, HER2-negative, advanced breast cancer: expanded analyses of subgroups from the randomized pivotal trial PALOMA-1/TRIO-18

Background

Palbociclib is an oral small-molecule inhibitor of cyclin-dependent kinases 4 and 6. In the randomized, open-label, phase II PALOMA-1/TRIO-18 trial, palbociclib in combination with letrozole improved progression-free survival (PFS) compared with letrozole alone as first-line treatment of estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative, advanced breast cancer (20.2 months versus 10.2 months; hazard ratio (HR) = 0.488, 95 % confidence interval (CI) 0.319–0.748; one-sided p = 0.0004). Grade 3–4 neutropenia was the most common adverse event (AE) in the palbociclib + letrozole arm. We now present efficacy and safety analyses based on several specific patient and tumor characteristics, and present in detail the clinical patterns of neutropenia observed in the palbociclib + letrozole arm of the overall safety population.

Methods

Postmenopausal women (n = 165) with ER+, HER2-negative, advanced breast cancer who had not received any systemic treatment for their advanced disease were randomized 1:1 to receive either palbociclib in combination with letrozole or letrozole alone. Treatment continued until disease progression, unacceptable toxicity, consent withdrawal, or death. The primary endpoint was PFS. We now analyze the difference in PFS for the treatment populations by subgroups, including age, histological type, history of prior neoadjuvant/adjuvant systemic treatment, and sites of distant metastasis, using the Kaplan-Meier method. HR and 95 % CI are derived from a Cox proportional hazards regression model.

Results

A clinically meaningful improvement in median PFS and clinical benefit response (CBR) rate was seen with palbociclib + letrozole in every subgroup evaluated. Grade 3–4 neutropenia was the most common AE with palbociclib + letrozole in all subgroups. Analysis of the frequency of neutropenia by grade during the first six cycles of treatment showed that there was a downward trend in Grade 3–4 neutropenia over time. Among those who experienced Grade 3–4 neutropenia, 71.7 % had no overlapping infections of any grade and none had overlapping Grade 3–4 infections.

Conclusion

The magnitude of clinical benefit seen with the addition of palbociclib to letrozole in improving both median PFS and CBR rate is consistent in nearly all subgroups analyzed, and consistent with that seen in the overall study population. The safety profile of the combination treatment in all subgroups was also comparable to that in the overall safety population of the study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0721-5) contains supplementary material, which is available to authorized users.

Genomic Characterization of Primary Invasive Lobular Breast Cancer

Purpose

Invasive lobular breast cancer (ILBC) is the second most common histologic subtype after invasive ductal breast cancer (IDBC). Despite clinical and pathologic differences, ILBC is still treated as IDBC. We aimed to identify genomic alterations in ILBC with potential clinical implications.

Methods

From an initial 630 ILBC primary tumors, we interrogated oncogenic substitutions and insertions and deletions of 360 cancer genes and genome-wide copy number aberrations in 413 and 170 ILBC samples, respectively, and correlated those findings with clinicopathologic and outcome features.

Results

Besides the high mutation frequency of CDH1 in 65% of tumors, alterations in one of the three key genes of the phosphatidylinositol 3-kinase pathway, PIK3CA, PTEN, and AKT1, were present in more than one-half of the cases. HER2 and HER3 were mutated in 5.1% and 3.6% of the tumors, with most of these mutations having a proven role in activating the human epidermal growth factor receptor/ERBB pathway. Mutations in FOXA1 and ESR1 copy number gains were detected in 9% and 25% of the samples. All these alterations were more frequent in ILBC than in IDBC. The histologic diversity of ILBC was associated with specific alterations, such as enrichment for HER2 mutations in the mixed, nonclassic, and ESR1 gains in the solid subtype. Survival analyses revealed that chromosome 1q and 11p gains showed independent prognostic value in ILBC and that HER2 and AKT1 mutations were associated with increased risk of early relapse.

Conclusion

This study demonstrates that we can now begin to individualize the treatment of ILBC, with HER2, HER3, and AKT1 mutations representing high-prevalence therapeutic targets and FOXA1 mutations and ESR1 gains deserving urgent dedicated clinical investigation, especially in the context of endocrine treatment.