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Invasive lobular breast cancer (ILC) is characterized by a relatively high risk for late recurrence and a unique metastatic pattern with an increased risk for metastasis to gynecologic organs and peritoneum. We present a unique case of recurrent ILC with metastasis to the abdominal peritoneum as well as the uterine myometrium and cervix. Treatment was complicated by the discovery of concomitant uterine carcinosarcoma. This patient was effectively treated with a combination of hormonal therapy for her metastatic ILC and a combination of chemotherapy and immunotherapy for uterine carcinosarcoma. Molecular evaluation revealed a characteristic CDH1 mutation within the ILC and a PI3KCA mutation within the uterine carcinosarcoma, both of which have been linked to epithelial-to-mesenchymal transitions. Examination of the tumor immune microenvironment revealed proportionally more cytotoxic NK cells. This robust immune infiltration may be an indicator of the response to immunotherapy observed in this tumor or a result of the metastatic breast cancer within the uterus. This report provides a characterization of the molecular and immunologic landscape in this case with metastatic ILC and uterine carcinosarcoma. [ABSTRACT FROM AUTHOR]

Metastatic spread of tumour cells to tissues and organs around the body is the most frequent cause of death from breast cancer. This has been modelled mainly using mouse models such as syngeneic mammary cancer or human in mouse xenograft models. These have limitations for modelling human disease progression and cannot easily be used for investigation of drug resistance and novel therapy screening. To complement these approaches, advances are being made in ex vivo and 3D in vitro models, which are becoming progressively better at reliably replicating the tumour microenvironment and will in the future facilitate drug development and screening. These approaches include microfluidics, organ-on-a-chip and use of advanced biomaterials. The relevant tissues to be modelled include those that are frequent and clinically important sites of metastasis such as bone, lung, brain, liver for invasive ductal carcinomas and a distinct set of common metastatic sites for lobular breast cancer. These sites all have challenges to model due to their unique cellular compositions, structure and complexity. The models, particularly in vivo, provide key information on the intricate interactions between cancer cells and the native tissue, and will guide us in producing specific therapies that are helpful in different context of metastasis. [ABSTRACT FROM AUTHOR]

Purpose: Accounting for about 15% of invasive lobular carcinomas and 1% of breast carcinomas, pleomorphic lobular carcinoma is known to be a rare histological subtype of invasive lobular carcinoma. Yet, it is more aggressive and produces a worse prognosis than other breast cancers. Ultimately, the present study compares the clinicopathological features of pleomorphic and invasive lobular breast carcinomas. Methods: In the study, we retrospectively evaluated the data of 262 patients with histological subtypes of classical and pleomorphic lobular cancers having been recruited for surgical operations. After resorting to Kolmogorov-Smirnov and Shapiro-Wilk tests to check the normality of distribution, the categorical and continuous variables were compared between the groups using the chi-square test and independent samples t test, respectively. In all analyses, we considered a P -value of <.05 to be statistically significant. Results: Our findings revealed that the groups with lobular and pleomorphic groups significantly differed by Ki-67 value, estrogen receptor negativity, grade, multicentricity, multifocality, surgical margin positivity, completion mastectomy, and metachronous contralateral tumor (P <.05). Conclusion: We discovered that pleomorphic type was associated with higher grades, estrogen receptor negativity, and Ki-67 expression. The incidence of metachronous breast cancer was high in the pleomorphic group, which may be a noteworthy finding to be considered in follow-ups. In addition, the high rates of multicentricity and multifocality of tumors in the pleomorphic group may be associated with increased surgical margin positivity and a higher likelihood of mastectomy. In a nutshell, our findings may guide patients and surgeons regarding the type of intervention and reconstruction options to be adopted in prospective surgeries. [ABSTRACT FROM AUTHOR]

Background: Despite histological and molecular differences between invasive lobular carcinoma (ILC) and invasive carcinoma of no special type, according to national treatment guidelines no distinction is made regarding the use of (neo)adjuvant chemotherapy. Studies on the long‐term outcome of chemotherapy in patients with ILC are scarce and show inconclusive results. Methods: All patients with estrogen receptor (ER)–positive, human epidermal growth factor receptor 2 (HER2)–negative ILC with an indication for chemotherapy treated with adjuvant endocrine therapy were selected from the Erasmus Medical Center Breast Cancer database. Cox proportional hazards models were used to estimate the effect of chemotherapy on recurrence‐free survival (RFS), breast cancer–specific survival (BCSS), and overall survival (OS). Results: A total of 520 patients were selected, of whom 379 were treated with chemotherapy and 141 were not. Patients in the chemotherapy group were younger (51 vs. 61 years old; p <.001), had a higher T status (T3+, 33% vs. 14%; p <.001), and more often had lymph node involvement (80% vs. 49%; p <.001) in comparison to the no‐chemotherapy group. After adjusting for confounders, chemotherapy treatment was not associated with better RFS (hazard ratio [HR], 1.20; 95% confidence interval [CI], 0.63–2.31), BCSS (HR, 1.24; 95% CI, 0.60–2.58), or OS (HR, 0.97; 95% CI, 0.56–1.66). This was also reflected by adjusted Cox survival curves in the chemotherapy versus no‐chemotherapy group for RFS (75% vs. 79%), BCSS (80% vs. 84%), and OS (72% vs. 71%). Conclusions: Chemotherapy is not associated with improved RFS, BCSS, or OS for patients with ER+/HER2− ILC treated with adjuvant endocrine therapy and with an indication for chemotherapy. Chemotherapy is not associated with improved recurrence‐free survival, breast cancer–specific survival, or overall survival for patients with estrogen receptor–positive/human epidermal growth factor receptor 2–negative invasive lobular carcinoma treated with endocrine therapy and with an indication for chemotherapy. [ABSTRACT FROM AUTHOR]

Invasive lobular carcinoma (ILC) is a special breast cancer type characterized by noncohesive growth and E‐cadherin loss. Focal activation of P‐cadherin expression in tumor cells that are deficient for E‐cadherin occurs in a subset of ILCs. Switching from an E‐cadherin deficient to P‐cadherin proficient status (EPS) partially restores cell–cell adhesion leading to the formation of cohesive tubular elements. It is unknown what conditions control EPS. Here, we report on EPS in ILC metastases in the large bowel. We reviewed endoscopic colon biopsies and colectomy specimens from a 52‐year‐old female (index patient) and of 18 additional patients (reference series) diagnosed with metastatic ILC in the colon. EPS was assessed by immunohistochemistry for E‐cadherin and P‐cadherin. CDH1/E‐cadherin mutations were determined by next‐generation sequencing. The index patient's colectomy showed transmural metastatic ILC harboring a CDH1/E‐cadherin p.Q610* mutation. ILC cells displayed different growth patterns in different anatomic layers of the colon wall. In the tunica muscularis propria and the tela submucosa, ILC cells featured noncohesive growth and were E‐cadherin‐negative and P‐cadherin‐negative. However, ILC cells invading the mucosa formed cohesive tubular elements in the intercryptal stroma of the lamina propria mucosae. Inter‐cryptal ILC cells switched to a P‐cadherin‐positive phenotype in this microenvironmental niche. In the reference series, colon mucosa infiltration was evident in 13 of 18 patients, one of which showed intercryptal EPS and conversion to cohesive growth as described in the index patient. The large bowel is a common metastatic site in ILC. In endoscopic colon biopsies, the typical noncohesive growth of ILC may be concealed by microenvironment‐induced EPS and conversion to cohesive growth. [ABSTRACT FROM AUTHOR]

Invasive lobular breast cancer (ILC) is characterized by a relatively high risk for late recurrence and a unique metastatic pattern with an increased risk for metastasis to gynecologic organs and peritoneum. We present a unique case of recurrent ILC with metastasis to the abdominal peritoneum as well as the uterine myometrium and cervix. Treatment was complicated by the discovery of concomitant uterine carcinosarcoma. This patient was effectively treated with a combination of hormonal therapy for her metastatic ILC and a combination of chemotherapy and immunotherapy for uterine carcinosarcoma. Molecular evaluation revealed a characteristic CDH1 mutation within the ILC and a PI3KCA mutation within the uterine carcinosarcoma, both of which have been linked to epithelial-to-mesenchymal transitions. Examination of the tumor immune microenvironment revealed proportionally more cytotoxic NK cells. This robust immune infiltration may be an indicator of the response to immunotherapy observed in this tumor or a result of the metastatic breast cancer within the uterus. This report provides a characterization of the molecular and immunologic landscape in this case with metastatic ILC and uterine carcinosarcoma.

18F-fluoroestradiol (18F-FES) is a Food and Drug Administration-approved radiopharmaceutical used for molecular imaging of the estrogen receptor (ER). When combined with PET, 18F-FES may improve the diagnosis of ER-positive breast cancer in the metastatic setting and provide insights into tumor heterogeneity. In this article, we review data on the use of 18F-FES imaging for treatment selection, staging, imaging lobular breast cancer, and the novel breast specific imaging tool, dedicated breast PET.

Purpose: To compare the diagnostic performance (detection, assessment of correct disease extent and multifocality/centricity) of Contrast-Enhanced Mammography (CEM) Versus Breast Magnetic Resonance (MRI) in the study of lobular neoplasms. Methods: We retrospectively selected all the patients who underwent surgery for a lobular breast neoplasm, either an in situ or an invasive tumor, and had undergone both breast CEM and MRI examinations during the pre-surgical planning. Wilcoxon Signed Rank test was performed to assess the differences between size measurements using the different methods and the post-surgical pathological measurements, considered the gold standard. The agreement in identifying multifocality/multicentricity among the different methods and the pathology was assessed using the Kappa statistics. Results: We selected 19 patients, of which one presented a bilateral neoplasm. Then, the images of these 19 patients were analyzed, for a total of 52 malignant breast lesions. We found no significant differences between the post-surgical pathological size of the lesions and the calculated size with CEM and MRI (p-value of the difference respectively 0.71 and 0.47). In all 20 cases, neoplasm detection was possible both with CEM and MRI. CEM and MRI showed an excellent ability to identify multifocal and multicentric cases (K statistic equal to 0.93 for both the procedures), while K statistic was 0.11 and 0.59 for FFDM and US, respectively. Conclusion: The findings of this study suggest that CEM is a reliable imaging technique in the preoperative setting of patients with lobular neoplasm, with comparable results to breast MRI. [ABSTRACT FROM AUTHOR]

Invasive lobular carcinoma (ILC) is a low‐ to intermediate‐grade histological breast cancer type caused by mutational inactivation of E‐cadherin function, resulting in the acquisition of anchorage independence (anoikis resistance). Most ILC cases express estrogen receptors, but options are limited in relapsed endocrine‐refractory disease as ILC tends to be less responsive to standard chemotherapy. Moreover, ILC can relapse after >15 years, an event that currently cannot be predicted. E‐cadherin inactivation leads to p120‐catenin‐dependent relief of the transcriptional repressor Kaiso (ZBTB33) and activation of canonical Kaiso target genes. Here, we examined whether an anchorage‐independent and ILC‐specific transcriptional program correlated with clinical parameters in breast cancer. Based on the presence of a canonical Kaiso‐binding consensus sequence (cKBS) in the promoters of genes that are upregulated under anchorage‐independent conditions, we defined an ILC‐specific anoikis resistance transcriptome (ART). Converting the ART genes into human orthologs and adding published Kaiso target genes resulted in the Kaiso‐specific ART (KART) 33‐gene signature, used subsequently to study correlations with histological and clinical variables in primary breast cancer. Using publicly available data for ERPOSHer2NEG breast cancer, we found that expression of KART was positively associated with the histological ILC breast cancer type (p < 2.7E‐07). KART expression associated with younger patients in all invasive breast cancers and smaller tumors in invasive ductal carcinoma of no special type (IDC‐NST) (<2 cm, p < 6.3E‐10). We observed associations with favorable long‐term prognosis in both ILC (hazard ratio [HR] = 0.51, 95% CI = 0.29–0.91, p < 3.4E‐02) and IDC‐NST (HR = 0.79, 95% CI = 0.66–0.93, p < 1.2E‐04). Our analysis thus defines a new mRNA expression signature for human breast cancer based on canonical Kaiso target genes that are upregulated in E‐cadherin deficient ILC. The KART signature may enable a deeper understanding of ILC biology and etiology. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

Introduction: Mutations occurring in the CDH1 gene elevate the susceptibility to the development of hereditary diffuse gastric cancer (HDGC) as well as lobular breast cancer (LBC). LBCs with CDH1 germline mutations are classified as hereditary breast cancers, devoid of any indication of gastric carcinoma. As prophylactic gastrectomy is a recommended course of treatment for individuals with CDH1 mutations, it is advised that genetic testing be conducted for those who meet the criteria established by the National Comprehensive Cancer Network (NCCN). This study aimed to screen patients with HDGC for CDH1 testing and clinical management for the prevention of HDGC. Moreover, patients with LBC are tested for CDH1 mutation. Materials and Methods: In this multicenter study, thirty-one patients with HDGC were selected among 615 patients and admitted for CDH1 mutation testing. PCR for all 16 exons of CDH1 and Sanger sequencing were performed. Patients with LBC who are negative for BRCA1/2 were also included in this study regardless of gastric cancer history. Results: The results showed that 5.04% of patients with DGC were identified as HDGC of which 9.6% of individuals had a pathogenic CDH1 mutation and only 15.38% of cases with a family history carried germline mutation in CDH1. Furthermore, 7.6% of patients with LBC and negative for a family history of gastric cancer have CDH1 mutation. Discussion: All patients who met the NCCN criteria were not CDH1 mutation-positive, indicating other genes should be involved in DGC. Moreover, patients with LBC and negative for BRCA1/2 are recommended for testing the mutation in CDH1.

Abstract Invasive lobular carcinoma (ILC) is a special breast cancer type characterized by noncohesive growth and E‐cadherin loss. Focal activation of P‐cadherin expression in tumor cells that are deficient for E‐cadherin occurs in a subset of ILCs. Switching from an E‐cadherin deficient to P‐cadherin proficient status (EPS) partially restores cell–cell adhesion leading to the formation of cohesive tubular elements. It is unknown what conditions control EPS. Here, we report on EPS in ILC metastases in the large bowel. We reviewed endoscopic colon biopsies and colectomy specimens from a 52‐year‐old female (index patient) and of 18 additional patients (reference series) diagnosed with metastatic ILC in the colon. EPS was assessed by immunohistochemistry for E‐cadherin and P‐cadherin. CDH1/E‐cadherin mutations were determined by next‐generation sequencing. The index patient's colectomy showed transmural metastatic ILC harboring a CDH1/E‐cadherin p.Q610* mutation. ILC cells displayed different growth patterns in different anatomic layers of the colon wall. In the tunica muscularis propria and the tela submucosa, ILC cells featured noncohesive growth and were E‐cadherin‐negative and P‐cadherin‐negative. However, ILC cells invading the mucosa formed cohesive tubular elements in the intercryptal stroma of the lamina propria mucosae. Inter‐cryptal ILC cells switched to a P‐cadherin‐positive phenotype in this microenvironmental niche. In the reference series, colon mucosa infiltration was evident in 13 of 18 patients, one of which showed intercryptal EPS and conversion to cohesive growth as described in the index patient. The large bowel is a common metastatic site in ILC. In endoscopic colon biopsies, the typical noncohesive growth of ILC may be concealed by microenvironment‐induced EPS and conversion to cohesive growth.

Gastrointestinal tract breast cancer (BC) metastases represent a rare event and generally originate from the lobular subtype. Duodenal involvement was rarely described in previous case series. Abdominal symptoms are extremely unspecific and misleading. Diagnosis is challenging, and it consists of a few mandatory steps from radiological examinations to histological and immunohistochemical analyses. Here, we presented the clinical case of a 54-year-old postmenopausal woman who was hospitalized for vomiting and jaundice, presenting increased level of liver enzymes and minimal main bile duct and choledocus dilatation at abdominal ultrasonography. She underwent breast-conserving surgery and axillary lymph node dissection for stage IIIB lobular BC, 5 years before. Metastatic infiltration of the duodenal bulb originating from lobular BC was proven histologically, through fine-needle aspiration during endoscopic ultrasonography. Treatment was established after multidisciplinary team evaluation, based on the clinical status and prognosis of the patient. Pancreaticoduodenectomy was performed, and final histological examination confirmed the secondary localization of lobular BC, infiltrating the duodenal and gastric wall, pancreas parenchyma, and surrounding tissues. No metastatic lymph nodes were found. After surgery, the patient underwent first line of adjuvant systemic treatment with fulvestrant and ribociclib. After a follow-up of 21 months, the patient was in good clinical condition, without signs of locoregional or distant recurrence. This report stressed on the importance of a tailored therapeutic approach. Although systemic therapy generally represents the preferred option, surgery should not be excluded if an oncological radical resection can be performed achieving acceptable locoregional disease control.

Simple Summary: Early-stage invasive lobular breast cancer (ILC) is characterized by multifocal tumor growth in the breast and a distinct pattern of late metastatic spread to other tissues. ILC cells are hypothesized to initiate metastases by exiting the breast via blood and lymphatic channels early in the disease process and then invading and eventually growing in distant tissues. Using in vitro ILC models, this study reveals that expression and activation of glucocorticoid receptor (GR), a stress-hormone-activated nuclear receptor and transcription factor, resulted in inhibition of ILC cell proliferation. Unexpectedly, GR activation also appeared to increase gene expression pathways that promote metastases. Thus, GR may be an important modulator of the low proliferative rate and high late metastatic risk associated with ILC. Estrogen receptor-positive (ER+) invasive lobular breast cancer (ILC) comprises about ~15% of breast cancer. ILC's unique genotypic (loss of wild type E-cadherin expression) and phenotypic (small individual round cancer cells that grow in discontinuous nests) are thought to contribute to a distinctive pattern of metastases to serosal membranes. Unlike invasive ductal carcinoma (IDC), ILC metastases often intercalate into the mesothelial layer of the peritoneum and other serosal surfaces. While ER activity is a known driver of ILC proliferation, very little is known about how additional nuclear receptors contribute to ILC's distinctive biology. In ER+ IDC, we showed previously that glucocorticoid receptor (GR) activity inhibits pro-proliferative gene expression and cell proliferation. Here we examined ER+ ILC models and found that GR activation similarly reduces S-phase entry gene expression and ILC proliferation. While slowing tumor growth rate, our data also suggest that GR activation results in an enhanced metastatic phenotype through increasing integrin-encoding gene expression, extracellular matrix protein adhesion, and mesothelial cell clearance. Moreover, in an intraductal mouse mammary gland model of ILC, we found that GR expression is associated with increased bone metastases despite slowed primary mammary tumor growth. Taken together, our findings suggest GR-mediated gene expression may contribute to the unusual characteristics of ILC biology. [ABSTRACT FROM AUTHOR]

Pathogenic germline variants (PGVs) in the CDH1 gene are associated with diffuse gastric and lobular breast cancer syndrome (DGLBC) and can increase the lifetime risk for both diffuse gastric cancer and lobular breast cancer. Given the risk for diffuse gastric cancer among individuals with CDH1 PGVs is up to 30–40%, prophylactic total gastrectomy is often recommended to affected individuals. Therefore, accurate interpretation of CDH1 variants is of the utmost importance for proper clinical decision-making. Herein we present a 45-year-old female, with lobular breast cancer and a father with gastric cancer of unknown pathology at age 48, who was identified to have an intronic variant of uncertain significance in the CDH1 gene, specifically c.833-9 C > G. Although the proband did not meet the International Gastric Cancer Linkage Consortium (IGCLC) criteria for gastric surveillance, she elected to pursue an upper endoscopy where non-targeted gastric biopsies identified a focus of signet ring cell carcinoma (SRCC). The proband then underwent a total gastrectomy, revealing numerous SRCC foci, but no invasive diffuse gastric cancer. Simultaneously, a genetic testing laboratory performed RNA sequencing to further analyze the CDH1 intronic variant, identifying an abnormal transcript from a novel acceptor splice site. The RNA analysis in conjunction with the patient's gastric foci of SRCC and family history was sufficient evidence for reclassification of the variant from uncertain significance to likely pathogenic. In conclusion, we report the first case of the CDH1 c.833-9 C > G intronic variant being associated with DGLBC and illustrate how collaboration among clinicians, laboratory personnel, and patients is crucial for variant resolution. [ABSTRACT FROM AUTHOR]

Purpose: Triple-negative invasive lobular carcinoma (TN-ILC) of breast cancer is a rare disease and the clinical outcomes and prognostic factors are not well-defined. Methods: Women with stage I–III TN-ILC or triple-negative invasive ductal carcinoma (TN-IDC) of the breast undergoing mastectomy or breast-conserving surgery between 2010 and 2018 in the National Cancer Database were included. Kaplan–Meier curves and multivariate Cox proportional hazard regression were used to compare overall survival (OS) and evaluate prognostic factors. Multivariate logistic regression was performed to analyze the factors associated with pathological response to neoadjuvant chemotherapy. Results: The median age at diagnosis for women with TN-ILC was 67 years compared to 58 years in TN-IDC (p < 0.001). There was no significant difference in the OS between TN-ILC and TN-IDC in multivariate analysis (HR 0.96, p = 0.44). Black race and higher TNM stage were associated with worse OS, whereas receipt of chemotherapy or radiation was associated with better OS in TN-ILC. Among women with TN-ILC receiving neoadjuvant chemotherapy, the 5-year OS was 77.3% in women with a complete pathological response (pCR) compared to 39.8% in women without any response. The odds of achieving pCR following neoadjuvant chemotherapy were significantly lower in women with TN-ILC compared to TN-IDC (OR 0.53, p < 0.001). Conclusion: Women with TN-ILC are older at diagnosis but have similar OS compared to TN-IDC after adjusting for tumor and demographic characteristics. Administration of chemotherapy was associated with improved OS in TN-ILC, but women with TN-ILC were less likely to achieve complete response to neoadjuvant therapy compared to TN-IDC. [ABSTRACT FROM AUTHOR]

Due to the increasing research into familial clustering of cancer entities, more and more genes are being identified in which mutations explain this clustering. Mutations in the cadherin 1 (CDH1) and catenin alpha 1 (CTNNA1) genes are considered to be causative for the occurrence of hereditary diffuse gastric cancer. Those affected show an incidence of gastric cancer of around 40% up to the age of 80 years and affected women show an incidence of 55% for the occurrence of lobular breast cancer. In 2020 updated international guidelines were published for the clinical management of patients with hereditary diffuse gastric cancer. When the specific test criteria are fulfilled, patients should undergo genetic testing for mutations in the CDH1 and CTNNA1 genes. In cases of the familial occurrence of diffuse gastric cancer and detection of a pathological mutation, a prophylactic total gastrectomy with D1 lymphadenectomy is recommended. Alternatively, or when pathological mutations are not detected, a gastroscopy should be performed annually with targeted and random biopsies. The occurrence of lobular breast cancer should be monitored annually by magnetic resonance imaging (MRI) from the age of 30 years onwards. A bilateral mastectomy for risk reduction should be discussed in a multidisciplinary setting. [ABSTRACT FROM AUTHOR]

Introduction: Mutations occurring in the CDH1 gene elevate the susceptibility to the development of hereditary diffuse gastric cancer (HDGC) as well as lobular breast cancer (LBC). LBCs with CDH1 germline mutations are classified as hered- itary breast cancers, devoid of any indication of gastric carcinoma. As prophylactic gastrectomy is a recommended course of treatment for individuals with CDH1 mu- tations, it is advised that genetic testing be conducted for those who meet the criteria established by the National Comprehensive Cancer Network (NCCN). This study aimed to screen patients with HDGC for CDH1 testing and clinical management for the prevention of HDGC. Moreover, patients with LBC are tested for CDH1 mutation. Materials and Methods: In this multicenter study, thirty-one patients with HDGC were selected among 615 patients and admitted for CDH1 mutation testing. PCR for all 16 exons of CDH1 and Sanger sequencing were performed. Patients with LBC who are negative for BRCA1/2 were also included in this study regardless of gastric cancer history. Results: The results showed that 5.04% of patients with DGC were identified as HDGC of which 9.6% of individuals had a pathogenic CDH1 mutation and only 15.38% of cases with a family history carried germline mutation in CDH1. Furthermore, 7.6% of patients with LBC and negative for a family history of gastric cancer have CDH1 mutation. Discussion: All patients who met the NCCN criteria were not CDH1 mutation-positive, indicating other genes should be involved in DGC. Moreover, patients with LBC and negative for BRCA1/2 are recommended for testing the mutation in CDH1. [ABSTRACT FROM AUTHOR]

Gastrointestinal tract breast cancer (BC) metastases represent a rare event and generally originate from the lobular subtype. Duodenal involvement was rarely described in previous case series. Abdominal symptoms are extremely unspecific and misleading. Diagnosis is challenging, and it consists of a few mandatory steps from radiological examinations to histological and immunohistochemical analyses. Here, we presented the clinical case of a 54-year-old postmenopausal woman who was hospitalized for vomiting and jaundice, presenting increased level of liver enzymes and minimal main bile duct and choledocus dilatation at abdominal ultrasonography. She underwent breast-conserving surgery and axillary lymph node dissection for stage IIIB lobular BC, 5 years before. Metastatic infiltration of the duodenal bulb originating from lobular BC was proven histologically, through fine-needle aspiration during endoscopic ultrasonography. Treatment was established after multidisciplinary team evaluation, based on the clinical status and prognosis of the patient. Pancreaticoduodenectomy was performed, and final histological examination confirmed the secondary localization of lobular BC, infiltrating the duodenal and gastric wall, pancreas parenchyma, and surrounding tissues. No metastatic lymph nodes were found. After surgery, the patient underwent first line of adjuvant systemic treatment with fulvestrant and ribociclib. After a follow-up of 21 months, the patient was in good clinical condition, without signs of locoregional or distant recurrence. This report stressed on the importance of a tailored therapeutic approach. Although systemic therapy generally represents the preferred option, surgery should not be excluded if an oncological radical resection can be performed achieving acceptable locoregional disease control. [ABSTRACT FROM AUTHOR]

The thirteenth annual workshop of the European Network for Breast Development and Cancer (ENBDC) Laboratories Annual Workshop took place on the 28–30 April 2022 in Weggis, Switzerland and focused on methods in mammary gland biology and breast cancer. Sixty scientists participated in the ENBDC annual workshop which had not been held in person since 2019 due to the global COVID-19 pandemic. Topics spanned the mammary gland biology field, ranging from lactation biology and embryonic development, single cell sequencing of the human breast, and stunning cutting-edge imaging of the mouse mammary gland and human breast as well as breast cancer research topics including invasive progression of the pre-invasive DCIS stage, metabolic determinants of endocrine therapy resistance, models for lobular breast cancer, and how mutational landscapes of normal breast during age and pregnancy determine cancer risk. The latest findings from participating researchers were presented through oral presentations and poster sessions and included plenty of unpublished work. [ABSTRACT FROM AUTHOR]

Gastrointestinal tract is an uncommon site of breast cancer metastasis. Rectal linitis plastica (RLP) is a rare presentation of rectal neoplasia, both primary and secondary, and refers to a diffuse infiltration of the wall by an infiltrating carcinoma. Diagnostic assessment of RLP may be challenging since cross-sectional imaging and endoscopic findings may be nonspecific, and endoscopic biopsies are frequently non-diagnostic due to the submucosal disease localization. Endoscopic ultrasound (EUS) with fine needle biopsy (FNB) is widely used for the diagnostic assessment of sub-epithelial lesions of upper and lower gastrointestinal tract. However, data about the use of EUS in case of rectal linitis plastica are very poor. We present a case of rectal metastasis as the first presentation of lobular breast cancer, presenting as rectal linitis plastica and diagnosed with EUS-FNB. [ABSTRACT FROM AUTHOR]

Breast cancer incidence has been steadily rising and is the leading cause of cancer death in women due to its high metastatic potential. Individual breast cancer subtypes are classified by both cell type of origin and receptor expression, namely estrogen, progesterone and human epidermal growth factor receptors (ER, PR and HER2). Recently, the importance and context-dependent role of glucocorticoid receptor (GR) expression in the natural history and prognosis of breast cancer subtypes have been uncovered. In ER-positive breast cancer, GR expression is associated with a better prognosis as a result of ER-GR crosstalk. GR appears to modulate ER-mediated gene expression resulting in decreased tumor cell proliferation and a more indolent cancer phenotype. In ER-negative breast cancer, including GR-positive triple-negative breast cancer (TNBC), GR expression enhances migration, chemotherapy resistance and cell survival. In invasive lobular carcinoma, GR function is relatively understudied, and more work is required to determine whether lobular subtypes behave similarly to their invasive ductal carcinoma counterparts. Importantly, understanding GR signaling in individual breast cancer subtypes has potential clinical implications because of the recent development of highly selective GR non-steroidal ligands, which represent a therapeutic approach for modulating GR activity systemically. • Glucocorticoid receptor (GR) is expressed in about 60% of both estrogen receptor positive (ER+) and negative (ER-) breast cancers. • Glucocorticoid receptor transcriptional activity is breast cancer subtype dependent (e.g. luminal versus basal). • GR activation inhibits proliferation in ER+ breast cancer cells. • GR-mediated gene expression pathways (e.g. EMT, cell survival, metastasis) are associated with worse TNBC prognosis. [ABSTRACT FROM AUTHOR]

Introduction: Invasive lobular breast cancer (ILC) is a diagnostic challenge due to the diversity of morphological features. The objective of the study was to investigate the presentation and local extent of ILC using various imaging techniques and to assess the correlation between imaging and molecular profile. Materials and methods: We reviewed 162 consecutive patients with ILC found on vacuum-assisted biopsy, who underwent evaluation of the lesion morphology and extent using ultrasound (US), mammography (MMG), and magnetic resonance imaging (MRI). Radiographic features were compared with ILC intrinsic subtype based on the expression of Ki-67 and estrogen, progesterone, and HER2 receptors. Results: A total of 113 mass lesions and 49 non-mass enhancements (NMEs) were found in MRI. Masses were typically irregular and spiculated, showing heterogeneous contrast enhancement, diffusion restriction, and type III enhancement curve. NMEs presented mainly as the area of focal or multiregional distribution with heterogeneous or clumped contrast enhancement, diffusion restriction, and type III enhancement curve. Lesion extent significantly varied between MRI and MMG/ultrasonography (USG) (P < 0.001) but did not differ between MGF and ultrasonography (USG). The larger the ILC, the higher the disproportion when lesion extent in MRI was compared with MMG (P < 0.001) and ultrasonography (USG) (P < 0.001). In the study group, there were 97 cases of luminal A subtype (59.9%), 54 cases of luminal B HER2-(33.3%), nine cases of luminal B HER2+ (5.5%), and two cases of triple negative (1.2%). The HER2 type was not found in the study group. We did not observe any significant correlation between molecular profile and imaging. Conclusion: MRI is the most effective technique for the assessment of ILC local extent, which is important for optimal treatment planning. Further studies are needed to investigate if the intrinsic subtype of ILC can be predicted by imaging features on MRI. [ABSTRACT FROM AUTHOR]

Background: Invasive lobular carcinoma (ILC) comprises 8–15 % of all invasive breast cancers and large population-based studies with >10 years of follow-up are rare. Whether ILC has a long-time prognosis different from that of invasive ductal carcinoma, (IDC) remains controversial. Purpose: To investigate the excess mortality rate ratio (EMRR) of patients with ILC and IDC and to correlate survival with clinical parameters in a large population-based cohort. Material and methods: From 1989 through 2006, we identified 17,481 patients diagnosed with IDC (n = 14,583) or ILC (n = 2898), younger than 76 years from two Swedish Regional Cancer Registries. Relative survival (RS) during 20 years of follow up was analysed. Results: ILC was significantly associated with older age, larger tumours, ER positivity and well differentiated tumours. We noticed an improved survival for patients with ILC during the first five years, excess mortality rate ratio (EMRR) 0.64 (CI 95 % 0.53–0.77). This was shifted to a significant decreased survival 10–15 years after diagnosis (EMRR 1.49, CI 95 % 1.16–1.93). After 20 years the relative survival rates were similar, 0.72 for ILC and 0.73 for IDC. Conclusions: During the first five years after surgery, the EMRR was lower for patients with ILC as compared to patients with IDC, but during the years 10–15 after surgery, we observed an increased EMRR for patients with ILC as compared to IDC. These EMRR between ILC and IDC were statistically significant but the absolute difference in excess mortality between the two groups was small.

IntroductionInvasive lobular breast cancer (ILC) is a diagnostic challenge due to the diversity of morphological features. The objective of the study was to investigate the presentation and local extent of ILC using various imaging techniques and to assess the correlation between imaging and molecular profile.Materials and methodsWe reviewed 162 consecutive patients with ILC found on vacuum-assisted biopsy, who underwent evaluation of the lesion morphology and extent using ultrasound (US), mammography (MMG), and magnetic resonance imaging (MRI). Radiographic features were compared with ILC intrinsic subtype based on the expression of Ki-67 and estrogen, progesterone, and HER2 receptors.ResultsA total of 113 mass lesions and 49 non-mass enhancements (NMEs) were found in MRI. Masses were typically irregular and spiculated, showing heterogeneous contrast enhancement, diffusion restriction, and type III enhancement curve. NMEs presented mainly as the area of focal or multiregional distribution with heterogeneous or clumped contrast enhancement, diffusion restriction, and type III enhancement curve. Lesion extent significantly varied between MRI and MMG/ultrasonography (USG) (P < 0.001) but did not differ between MGF and ultrasonography (USG). The larger the ILC, the higher the disproportion when lesion extent in MRI was compared with MMG (P < 0.001) and ultrasonography (USG) (P < 0.001). In the study group, there were 97 cases of luminal A subtype (59.9%), 54 cases of luminal B HER2− (33.3%), nine cases of luminal B HER2+ (5.5%), and two cases of triple negative (1.2%). The HER2 type was not found in the study group. We did not observe any significant correlation between molecular profile and imaging.ConclusionMRI is the most effective technique for the assessment of ILC local extent, which is important for optimal treatment planning. Further studies are needed to investigate if the intrinsic subtype of ILC can be predicted by imaging features on MRI.

Pathogenic CDH1 germline mutations are associated with lobular breast cancer in the so-called hereditary lobular breast cancer (HLBC) syndrome, without apparent correlation with the classic hereditary diffuse gastric cancer (HDGC). Recent international guidelines recommend CDH1 screening also in absence of diffuse gastric cancer (DGC) history. Genomic characteristics underlying gastric and breast tumorigenesis in this varied population of patients is still unclear. In this review we revised all CDH1 germline mutations described in literature associated with lobular breast cancer (LBC). We distinguish two subgroups of CDH1 mutant carriers: (a) 'mixed' HDGC syndrome, showing both DGC plus LBC and (b) HLBC, in which DGC is absent and the LBC phenotype is predominant. A higher frequency of CDH1 mutations was identified in the HLBC syndrome with an early age at LBC diagnosis; it is possible that LBCs with CDH1 germline mutations are an independent inherited syndrome. This evidence allows us to gain biological insight into the pathophysiological mechanisms responsible for the different phenotypes of the disease and potentially tailor the prophylactic and screening procedures. [ABSTRACT FROM AUTHOR]

Abstract Background The E-Cadherin gene (CDH1, Cadherin 1), located at 16q22.1 encodes for a calcium-dependent membranous glycoprotein with an important role in cellular adhesion and polarity maintenance. Methods To systematically determine E-Cadherin protein expression in normal and cancerous tissues, 14,637 tumor samples from 112 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Results E-Cadherin was strongly expressed in normal epithelial cells of most organs. From 77 tumor entities derived from cell types normally positive for E-Cadherin, 35 (45.5%) retained at least a weak E-Cadherin immunostaining in ≥99% of cases and 61 (79.2%) in ≥90% of cases. Tumors with the highest rates of E-Cadherin loss included Merkel cell carcinoma, anaplastic thyroid carcinoma, lobular carcinoma of the breast, and sarcomatoid and small cell neuroendocrine carcinomas of the urinary bladder. Reduced E-Cadherin expression was linked to higher grade (p = 0.0009), triple negative receptor status (p = 0.0336), and poor prognosis (p = 0.0466) in invasive breast carcinoma of no special type, triple negative receptor status in lobular carcinoma of the breast (p = 0.0454), advanced pT stage (p = 0.0047) and lymph node metastasis in colorectal cancer (p

Invasive lobular carcinoma is the second most common type of invasive carcinoma of the breast. Although rare, invasive lobular carcinoma can lead to gastric metastases, which may appear several years after the initial diagnosis. The diagnosis is difficult, either because of its rarity or because of overlapping symptoms and imaging findings with primary gastric carcinoma. Immunohistochemistry is the key to diagnosis. We report a case of a 40-year-old woman with a previous history of invasive lobular carcinoma of the breast 2 years before, who presented recurrent and nonspecific gastrointestinal symptoms. Imaging findings revealed linitis plastica and the biopsy showed the presence of signet ring cell neoplasia. After gastrectomy, immunohistochemistry demonstrated diffuse expression of GATA-3 and the presence of estrogen receptors in some neoplastic cells with CK20-, leading to the final diagnosis of gastric metastases from invasive lobular carcinoma of the breast.

The detection of circulating tumor DNA (ctDNA) in the plasma of cancer patients is emerging as a very sensitive and specific prognostic biomarker. Previous studies with ctDNA have focused on the ability of ctDNA detection to predict micrometastatic and eventual clinical metastatic relapse. There are few data on the role of ctDNA in monitoring response to local therapy. The present study reports the case of a patient with early-stage lobular breast cancer, with a detectable ctDNA test which resolved with local radiotherapy to the breast. This case suggests that ctDNA is sensitive enough to detect the response of minimal residual disease, localized in the breast, to radiation therapy, and thus may assist in providing indications for local breast cancer treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Inactivating mutations in the CDH1 gene, encoding the cell adhesion protein E-cadherin, cause hereditary diffuse gastric cancer syndrome (HDGC), as well as being a hallmark of sporadic diffuse gastric cancers and lobular breast cancers. We have previously identified AKT3 as a potential vulnerability in gastric cancers lacking CDH1 expression. This study aimed to test whether drugs which inhibit the AKT3-associated gene, discoidin domain receptor tyrosine kinase 2 (DDR2) specifically targeted cells deficient in E-cadherin. We demonstrated that cells and organoids lacking E-cadherin exhibited heightened sensitivity to dasatinib, a drug that targets multiple kinases including DDR2 and SRC. The CDH1 gene, encoding the cell adhesion protein E-cadherin, is one of the most frequently mutated genes in gastric cancer and inactivating germline CDH1 mutations are responsible for the cancer syndrome hereditary diffuse gastric cancer (HDGC). CDH1-deficient gastric cancers exhibit high AKT serine/threonine kinase 3 (AKT3) expression, but specific drugs against this AKT isoform are not available. We therefore used two publicly available datasets to identify AKT3-associated genes which could be used to indirectly target AKT3. Reactome analysis identified an enrichment of extracellular matrix remodelling genes in AKT3-high gastric cancers. Of the 51 genes that were significantly correlated with AKT3 (but not AKT1), discoidin domain receptor tyrosine kinase 2 (DDR2) showed the strongest positive association. Treatment of isogenic human cells and mouse gastric and mammary organoids with dasatinib, a small molecule inhibitor of multiple kinases including SRC, BCR-ABL and DDR2, preferentially slowed the growth and induced apoptosis of E-cadherin-deficient cells. Dasatinib treatment also preferentially slowed the growth of gastric and mammary organoids harbouring both Cdh1 and Tp53 mutations. In organoid models, dasatinib treatment was associated with decreased phosphorylation of total AKT, with a stronger effect seen in Cdh1-deficient organoids. Treatment with combinations of dasatinib and an inhibitor of AKT, MK2206, enhanced the effect of dasatinib in breast MCF10A cells. In conclusion, targeting the DDR2-SRC-AKT3 axis with dasatinib represents a promising approach for the chemoprevention and chemotherapy of gastric and breast cancers lacking E-cadherin. [ABSTRACT FROM AUTHOR]

Purpose: Lobular breast cancer (LBC) accounts for ~ 15% of breast cancer. Here, we studied the frequency of pathogenic germline variants (PGVs) in an extended panel of genes in women affected with LBC. Methods: 302 women with LBC and 1567 without breast cancer were tested for BRCA1/2 PGVs. A subset of 134 LBC affected women who tested negative for BRCA1/2 PGVs underwent extended screening, including: ATM, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51D, and TP53.Results: 35 PGVs were identified in the group with LBC, of which 22 were in BRCA1/2. Ten actionable PGVs were identified in additional genes (ATM(4), CDH1(1), CHEK2(1), PALB2(2) and TP53(2)). Overall, PGVs in three genes conferred a significant increased risk for LBC. Odds ratios (ORs) were: BRCA1: OR = 13.17 (95%CI 2.83–66.38; P = 0.0017), BRCA2: OR = 10.33 (95%CI 4.58–23.95; P < 0.0001); and ATM: OR = 8.01 (95%CI 2.52–29.92; P = 0.0053). We did not detect an increased risk of LBC for PALB2, CDH1 or CHEK2. Conclusion: The overall PGV detection rate was 11.59%, with similar rates of BRCA1/2 (7.28%) PGVs as for other actionable PGVs (7.46%), indicating a benefit for extended panel genetic testing in LBC. We also report a previously unrecognised association of pathogenic variants in ATM with LBC. [ABSTRACT FROM AUTHOR]

Background: Vitamin D (vitD) may be involved in different extraskeletal conditions as well as skeletal muscle diseases. It has been hypothesized that, at least in part, a low level of vitD could contribute to facilitating cancer development. Breast cancer (BC) seems to be associated with low levels of vitD. Materials and methods: This was an observational retrospective evaluation of 87 women (mean age: 54 ± 12 years old) who underwent surgery for the treatment of BC. Our main purpose was to correlate the types of BC and the levels of vitD. Results: A positive significant correlation (R > 0.7) was found between non-invasive carcinoma in situ and 25(OH)D levels and age (R = 0.82, p < 0.05). A positive, but nonsignificant, correlation was reported between invasive ductal carcinoma and 25(OH)D and age (R = 0.45, p > 0.05). A negative but nonsignificant correlation was found between invasive lobular carcinoma and 25(OH)D and age (R = 0.24, p > 0.05). Discussion and Conclusions: We did not find a significant relationship between vitD and BC subtypes. Considering the positive significant correlation between vitD levels and age for in situ BC, although preliminary, our results seem to suggest a possible role of vitD in in situ BC. However, these findings need to be confirmed in larger studies. [ABSTRACT FROM AUTHOR]

Abstract Invasive lobular carcinoma (ILC) is the most common of the breast cancer special types, accounting for up to 15% of all breast cancer cases. ILCs are noted for their lack of E-cadherin function, which underpins their characteristic discohesive growth pattern, with cells arranged in single file and dispersed throughout the stroma. Typically, tumours are luminal in molecular subtype, being oestrogen and progesterone receptor positive, and HER2 negative. Since last reviewing the lobular literature (McCart Reed et al., Breast Cancer Res 17:12, 2015), there has been a considerable increase in research output focused on this tumour type, including studies into the pathology and management of disease, a high-resolution definition of the genomic landscape of tumours as well as the evolution of several potential therapeutic avenues. There abounds a huge amount of new data, which we will review herein.

Invasive lobular carcinoma (ILC) is the most common special type of invasive breast cancer (IBC), accounting for 5-15% of IBCs. The distinct histomorphology of ILC reflects a special tumor biology, the hallmark of which is the lack of E-cadherin expression. However, the occasional presence of E-cadherin expression and the presence of IBC of no special type (IBC, NST)-like morphologies in ILC and vice versa make the diagnosis challenging.  We present two cases of the alveolar variant of ILC, a diagnostically challenging entity. The first case is an 81-year-old female with two discrete right breast masses at 1 o'clock and 9 o'clock positions.  The second case is a 61-year-old female with two discrete left breast masses located at 11 o'clock and 12 o'clock positions. Core needle biopsies and subsequent mastectomy were performed in both cases. On histology, three tumor foci were identified in the first case. The 1 o'clock focus showed IBC, NST, grade 3/3, ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). The 9 o'clock focus revealed ILC, classic and alveolar variants, grade 2/3, while a nearby third incidental focus was ILC, alveolar variant, both supported by lack of E-cadherin and β-catenin immunostaining.  The second case showed ILC, alveolar variant, grade 1 with LCIS component in the 11 o'clock lesion on both biopsy and mastectomy specimens. The lesion at the 12 o'clock position was diagnosed as IBC, NST, grade 2 with high-grade DCIS and LCIS components.  It is challenging to distinguish the alveolar variant of ILC from IBC, NST, and in situ lesions because of the overlapping morphology and occasional E-cadherin expression. Altered adherence of lobular cells may also be due to loss of α-, β-, and γ-catenins, and cytoplasmic re-localization of p120-catenin. Therefore, in ILC, the lack of β-catenin can be used as an adjunct along with E-cadherin. Myoepithelial markers such as p63 and smooth muscle myosin heavy chain (SMMHC) can be used to distinguish the alveolar variant of ILC from LCIS., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Kolawole et al.)

Invasive lobular breast cancer (ILC) presents unique challenges and considerations in the realm of surgical management. Characterized by its distinct histological features, including the loss of E-cadherin expression and dys-cohesive growth pattern, ILC often poses diagnostic and therapeutic dilemmas for clinicians. This abstract explores the surgical landscape of ILC, focusing on its epidemiology, clinical presentation, diagnostic modalities, and surgical interventions. Emphasizing the importance of individualized treatment strategies, this narrative delves into the nuances of surgical decision-making, including the role of breast-conserving surgery versus mastectomy, axillary staging, and the significance of margin status. Additionally, advancements in surgical techniques, such as oncoplastic approaches and sentinel lymph node biopsy, are examined in the context of optimizing oncologic outcomes and preserving cosmesis. Through a comprehensive review of current literature and clinical guidelines, this overview aims to provide a nuanced understanding of the surgical considerations inherent to the management of invasive lobular breast cancer., Competing Interests: Disclosure The authors have stated that they have no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

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., Competing Interests: Declaration of competing interest No financial/personal interest from all Authors with the exception of Prof. Giuseppe Curigliano., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Invasive lobular carcinoma (ILC) comprises 8–15 % of all invasive breast cancers and large population-based studies with >10 years of follow-up are rare. Whether ILC has a long-time prognosis different from that of invasive ductal carcinoma, (IDC) remains controversial. To investigate the excess mortality rate ratio (EMRR) of patients with ILC and IDC and to correlate survival with clinical parameters in a large population-based cohort. From 1989 through 2006, we identified 17,481 patients diagnosed with IDC (n = 14,583) or ILC (n = 2898), younger than 76 years from two Swedish Regional Cancer Registries. Relative survival (RS) during 20 years of follow up was analysed. ILC was significantly associated with older age, larger tumours, ER positivity and well differentiated tumours. We noticed an improved survival for patients with ILC during the first five years, excess mortality rate ratio (EMRR) 0.64 (CI 95 % 0.53–0.77). This was shifted to a significant decreased survival 10–15 years after diagnosis (EMRR 1.49, CI 95 % 1.16–1.93). After 20 years the relative survival rates were similar, 0.72 for ILC and 0.73 for IDC. During the first five years after surgery, the EMRR was lower for patients with ILC as compared to patients with IDC, but during the years 10–15 after surgery, we observed an increased EMRR for patients with ILC as compared to IDC. These EMRR between ILC and IDC were statistically significant but the absolute difference in excess mortality between the two groups was small. • This is a large population-based study with more than 17,000 patients with a follow up exciding 20 years. • There is clinically important differences between invasive lobular and ductal carcinoma of the breast. • Lobular carcinoma shows better survival during the first period but significantly worse at the late period of observation. [ABSTRACT FROM AUTHOR]

Invasive lobular carcinoma accounts for 5%–15% of all invasive breast cancers, with a marked increase in incidence rates over the past two decades. Distinctive biological hallmarks of invasive lobular carcinoma include the loss of cell adhesion molecule E-cadherin leading to cells with a discohesive morphology, proliferating into single-file strands and estrogen receptor positivity. These key molecular features can make diagnosis difficult, as invasive lobular carcinoma is challenging to detect both physically and with current standard imaging. Treatment of invasive lobular carcinoma strongly favors endocrine therapy due to low chemosensitivity and lower rates of pathological response as a result. This review will summarize the distinct biological and molecular features of invasive lobular carcinoma, focusing on the diagnostic challenges faced and the subsequent surgical and medical management strategies. Prospective therapeutic options will also be explored, highlighting how furthering our understanding of the unique biology of lobular breast carcinoma is essential in guiding and informing the treatment of patients in the future.

Invasive lobular carcinoma accounts for 5%–15% of all invasive breast cancers, with a marked increase in incidence rates over the past two decades. Distinctive biological hallmarks of invasive lobular carcinoma include the loss of cell adhesion molecule E-cadherin leading to cells with a discohesive morphology, proliferating into single-file strands and estrogen receptor positivity. These key molecular features can make diagnosis difficult, as invasive lobular carcinoma is challenging to detect both physically and with current standard imaging. Treatment of invasive lobular carcinoma strongly favors endocrine therapy due to low chemosensitivity and lower rates of pathological response as a result. This review will summarize the distinct biological and molecular features of invasive lobular carcinoma, focusing on the diagnostic challenges faced and the subsequent surgical and medical management strategies. Prospective therapeutic options will also be explored, highlighting how furthering our understanding of the unique biology of lobular breast carcinoma is essential in guiding and informing the treatment of patients in the future. [ABSTRACT FROM AUTHOR]

Invasive lobular carcinoma (ILC) is the most common of the breast cancer special types, accounting for up to 15% of all breast cancer cases. ILCs are noted for their lack of E-cadherin function, which underpins their characteristic discohesive growth pattern, with cells arranged in single file and dispersed throughout the stroma. Typically, tumours are luminal in molecular subtype, being oestrogen and progesterone receptor positive, and HER2 negative. Since last reviewing the lobular literature (McCart Reed et al., Breast Cancer Res 17:12, 2015), there has been a considerable increase in research output focused on this tumour type, including studies into the pathology and management of disease, a high-resolution definition of the genomic landscape of tumours as well as the evolution of several potential therapeutic avenues. There abounds a huge amount of new data, which we will review herein. [ABSTRACT FROM AUTHOR]

Background: Invasive lobular breast cancer (BC) is the second most common BC subtype. Prognostic parameters (tumor classification, lymph node status, histologic grade, Oncotype DX recurrence score [RS], progesterone receptor status, and Ki67 index) were retrospectively studied in a large, prospective clinical trial encompassing 2585 patients who had hormone receptor‐positive early BC (the West German Study Group PlanB trial). Methods: BCs were centrally reviewed and classified as lobular (n = 353; 14%) or nonlobular (n = 2232; 86%). The median follow‐up was 60 months. Five‐year disease‐free survival (DFS) estimates were obtained using the Kaplan‐Meier method. Prognostic parameters were evaluated using Cox proportional hazard models. Results: Lobular BC was associated with higher tumor classification, higher lymph node status, lower histologic grade, lower Ki67 index, and low or intermediate RS. The prevalence of high RS (RS range, 26‐100) was 3‐fold lower in patients who had lobular BC compared with those who had nonlobular BC (8% vs 24%; P <.001). However, 5‐year DFS estimates for lobular and nonlobular BC were similar (92.1% and 92.3%, respectively; P =.673). In multivariate analyses, prognostic parameters for DFS in lobular BC included grade 3 (hazard ratio, 5.06; 95% CI, 1.91‐13.39) and a pathologic lymph node status (pN) of pN3 (hazard ratio, 12.16; 95% CI, 3.87‐38.24), but not RS. By contrast, prognostic parameters in nonlobular BC included grade 3 (hazard ratio, 1.65; 95% CI, 1.11‐2.44), pN3 (hazard ratio, 3.68; 95% CI, 1.60‐8.46), and high RS (hazard ratio, 2.49; 95% CI, 1.69‐3.68). Conclusions: Lobular BC is associated with low and intermediate RS, although 5‐year DFS is similar to that of nonlobular BC. The effect of the RS in lobular BC appears to be distinct from that in nonlobular BC. For risk assessment, the RS needs to be complemented by clinicopathologic parameters for therapy decision making. The prognostic impact of the Oncotype DX recurrence score in lobular breast cancer is distinct from that in nonlobular breast cancer. Correct histologic classification is a prerequisite for the adequate clinical utilization of prognostic gene expression profiles. [ABSTRACT FROM AUTHOR]

Invasive lobular carcinoma (ILC) has been reported to be less responsive to neoadjuvant chemotherapy (NAC) than invasive ductal carcinoma (IDC). We sought to determine whether ILC histology indeed predicts poor response to NAC by analyzing tumor characteristics such as protein expression, gene expression, and imaging features, and by comparing NAC response rates to those seen in IDC after adjustment for these factors. We combined datasets from two large prospective NAC trials, including in total 676 patients, of which 75 were of lobular histology. Eligible patients had tumors ≥3 cm in diameter or pathologic documentation of positive nodes, and underwent serial biopsies, expression microarray analysis, and MRI imaging. We compared pathologic complete response (pCR) rates and breast conservation surgery (BCS) rates between ILC and IDC, adjusted for clinicopathologic factors. On univariate analysis, ILCs were significantly less likely to have a pCR after NAC than IDCs (11 vs. 25 %, p = 0.01). However, the known differences in tumor characteristics between the two histologic types, including hormone receptor (HR) status, HER2 status, histological grade, and p53 expression, accounted for this difference with the lowest pCR rates among HR+/HER2- tumors in both ILC and IDC (7 and 5 %, respectively). ILC which were HR- and/or HER2+ had a pCR rate of 25 %. Expression subtyping, particularly the NKI 70-gene signature, was correlated with pCR, although the small numbers of ILC in each group precluded significant associations. BCS rate did not differ between IDC and ILC after adjusting for molecular characteristics. We conclude that ILC represents a heterogeneous group of tumors which are less responsive to NAC than IDC. However, this difference is explained by differences in molecular characteristics, particularly HR and HER2, and independent of lobular histology.

Abstract Background Metastases to the thyroid gland are more frequent than previously thought, although most of them are occult or not clinically relevant. Overall, only 42 cases of metastases to thyroid from breast cancer have been reported thus far. Here we report the case of a patient with breast cancer metastatic to the thyroid. We also review the 42 previously reported cases (published between 1962 and 2012). This is the first review about metastases to thyroid gland from breast cancer. Case presentation A 64-year-old woman of Caucasian origin was diagnosed with a lobular invasive carcinoma of the breast (luminal A, stage II). She received adjuvant chemotherapy, followed by endocrine therapy. During follow-up, fine-needle cytology of a thyroid nodule revealed malignant cells that were estrogen-positive, which suggested a diagnosis of metastases to the thyroid. Imaging did not reveal any other metastatic site and showed only enlargement of the left thyroid lobe and an inhomogeneous pattern of colloid and cystic degeneration and calcifications. The patient underwent left hemithyroidectomy. Histology of thyroid tissue showed a colloid goitre containing dispersed small atypical neoplastic cells with eccentric nuclei. Immunohistochemistry showed cytokeratin-19 and oestrogen receptor, but not tireoglobulin, e-cadherin or cytokeratin-7, thereby confirming metastases from a lobular breast carcinoma. Hormonal treatment is ongoing. Conclusion This case report and first review of the literature on metastases to thyroid from breast cancer highlight the importance of a correct early diagnostic work-up in such cases. Indeed, a primary lesion should be distinguished from metastases given the different treatment protocol related to primary cancer and the clinical impact on prognosis.

Breast cancer is the most common tumour in women. Only 5–15% of breast cancer patients have distant metastases at diagnosis. Here we describe the case of a previously healthy 43-year-old woman with nausea, postprandial epigastric pain, and constipation as the first clinical presentation of breast cancer. Total colonoscopy revealed colon metastases and the immunohistochemical profile favoured primitive invasive lobular carcinoma of the breast. Gastrointestinal tract metastases are more frequent in lobular histology of breast cancer. Stomach and small intestine are the most common metastatic sites, while colon metastases are a rare occurrence.

Introduction: Breast cancer is a complex and heterogenous disease that affects millions of individuals worldwide, irrespective of age or ethnicity. With numerous subtypes and varying degrees of aggressiveness, breast cancer presents a significant challenge in terms of diagnosis, treatment and management. Case Report: We report the case of a 57-year-old woman who presented to the Surgery Department, accusing breast discomfort, shortness of breath and abdominal pain. A CT was performed and revealed a diffuse infiltrative lesion spread through the right breast and axillary lymph nodes, bilateral pleural effusion, peritoneal carcinomatosis, ascites and bone metastases. A biopsy of the right breast, thoracocentesis and paracentesis was performed and sent to the Pathology Department. Microscopically, an infiltrative tumoral proliferation was identified, corresponding to an invasive lobular breast carcinoma with signet ring cell component, without in situ component. The tumoral cells were immunohistochemically positive for Citokeratin 7, GATA3 and ER. In the pleural and ascites fluid tumoral cells were identified, with marked cyto-nuclear pleomorphism, that were forming pseudo-glandular structures. Immunohistochemically, the tumoral cells were positive for GATA3 and ER markers. Discussions : The immunohistochemical profile of the tumoral cells from pleural effusion and ascites fluids suggest their mammary primary origin. The particularity of the case is emphasized by the fact that the patient is at her first admission and all the specimens collected: breast biopsy, pleural and ascites fluid, all confirmed the presence of malignant cells. In addition to this, the CT scan showed signs of bone metastases and peritoneal carcinomatosis. Conclusions: This case illustrates the importance of interdisciplinary management of the cases with multiple determinations and the weight of immunohistochemistry on correlating all patient's specimens and giving only one diagnosis. [ABSTRACT FROM AUTHOR]