Metaplastic carcinoma of the breast

Curative Approaches for Metaplastic Breast Cancer: A Retrospective Cohort Outcome Review

PURPOSE

Metaplastic breast cancer (MBC) is a rare and heterogeneous breast cancer subtype, and there are critical gaps in our understanding of its long-term outcomes. This retrospective cohort study aimed to address these gaps by scrutinizing the pathologic and clinical aspects of MBC to enhance clinical decision-making and refine patient care strategies.

METHODS AND MATERIALS

This registry-based retrospective cohort study included women aged ≥21 years diagnosed with MBC or matrix-producing carcinoma. The data were obtained from January 2001 to August 2020 from the Joint Breast Cancer Registry of Singapore Health Services, which included 23,935 patients. Demographic and clinicopathologic characteristics, neoadjuvant chemotherapy responses, and survival outcomes were analyzed. Statistical assessments involved univariate and multivariate Cox proportional hazards models and Kaplan-Meier survival analyses.

RESULTS

This study enrolled 170 patients; 87.1% had non-metastatic disease, and 12.9% had metastatic disease. The age of patients at diagnosis ranged from 46 to 65 years (median, 56 years). The cohort's predominant characteristics were triple negative breast cancer (64%), advanced clinical stage (77.6%), node negativity (67.6%), and grade 3 disease (74.1%). In patients receiving neoadjuvant chemotherapy with curative intent treatment (17.6%), neoadjuvant chemotherapy yielded a pathologic complete response of 19.2% and a disease progression rate of 46.2%. Multivariate analysis showed that adjuvant radiation therapy significantly improved overall survival and disease-free survival, with hazard ratios of 0.29 (95% CI, 0.13-0.62; P < .005) and 0.23 (95% CI, 0.10-0.50; P < .005), respectively. Clinical T3 and T4 stages and nodal involvement were associated with poor outcomes. Stable disease after neoadjuvant chemotherapy was associated with poor overall survival and disease-free survival.

CONCLUSIONS

This study sheds light on the complex landscape of MBC and emphasizes the pivotal role of adjuvant radiation therapy in enhancing patient outcomes. Despite advancements, challenges persist that warrant continued research to refine neoadjuvant chemotherapy strategies and delve into the nuanced factors that influence treatment responses.

Chondrolipoma of the Breast: A Myofibroblastoma Variant or a Distinct Lesion?

The entity commonly referred to as chondrolipoma is a rare and enigmatic breast lesion with unclear histogenesis and a complete lack of molecular characterization. It is uncertain whether it represents a hamartoma, choristoma, or a distinct neoplasm, including possibly a variant of mammary-type myofibroblastoma. We report two additional chondrolipomatous lesions of the breast. The lesions had varying histologic and immunohistochemical features similar to myofibroblastoma, including the loss of retinoblastoma (Rb) protein expression in one lesion. Molecular analysis by chromosomal microarray analysis performed on a second lesion did not demonstrate a loss of 13q14 or 16q typical of myofibroblastoma. Our findings further support the concept that at least a subset of breast lesions that historically have been classified as chondrolipoma are related to myofibroblastoma. However, the lack of myofibroblastoma-specific molecular alterations in one lesion suggests chondrolipomas may also have varying origins.

Epidemiology, site-specific characteristics and survival of carcinosarcoma: a retrospective study based on SEER database

OBJECTIVES

Carcinosarcoma (CS) is a rare and biphasic malignancy characterised by a highly invasive biological nature and poor prognosis. This study explored the epidemiology, site-specific characteristics and survival outcome of CS.

DESIGN

We conducted a retrospective study in the Surveillance, Epidemiology and End Results (SEER) database (1975-2018) for primary CS.

SETTING AND PARTICIPANTS

SEER database includes publicly available information from regional and state cancer registries in the US centres. A total of 5042 CS patients were identified. We selected the top five anatomic CS (uterus, double adnexa, lung, bladder and breast) patients for further analysis.

PRIMARY OUTCOME MEASURES

Incidence was estimated by geographical region, age, sex, race, stage and primary site. Trends were calculated using joinpoint regression. The cancer-specific survival (CSS) rate and initial treatment were summarised.

RESULTS

Nearly 80% of CS occurred in the uterus and double adnexa, followed by lung, bladder and breast. The elderly and black population presented the highest age-adjusted rate of CS. The rates of distant metastasis in CS progressively increased from 1989 to 2018. Atlanta was the area with the highest incidence at 0.7 per 100 000. Pulmonary and bladder CS more frequently occurred in men and were diagnosed with regional stage. Distant metastasis was mostly found in ovary/fallopian tube CS. Radiotherapy was more commonly applied in uterine CS, while adnexa CS cases were more likely to receive chemotherapy. Multiple treatments were more used in breast CS. Pulmonary CS seemed to suffer worse CSS (median: 9.92 months), for which radiotherapy might not provide survival benefits (HR 0.60, 95% CI 0.42 to 0.86). Compared with the common histological types in each site, CS had the shortest survival.

CONCLUSIONS

CS has unique clinical features in each primary site. Substantial prognosis variances exist based on tumour locations. The aggressive course is the common feature in CS at all sites.

Clinicopathological characteristics and prognosis of metaplastic breast cancer versus triple-negative invasive ductal carcinoma: a retrospective analysis

BACKGROUND

Metaplastic breast cancer(MBC) is a specific pathological type of invasive breast cancer. There are few studies related to MBC due to its rarity. This study aimed to analyse the differences in clinicopathological characteristics and prognosis between Metaplastic breast cancer and triple-negative invasive ductal carcinoma (TN-IDC).

METHODS

We retrospectively compared the clinicopathological characteristics of patients diagnosed with MBC and TN-IDC at the Fourth Hospital of Hebei Medical University between 2011 and 2020 in a 1:2 ratio. The log-rank test was used to compare the two groups' disease-free survival (DFS) and overall survival (OS). For MBCs, we performed univariate and multivariate analyses using the Cox proportional hazards model to determine the characteristics that impacted OS and DFS.

RESULTS

A total of 81 patients with MBC and 162 patients with TN-IDC were included in this study. At initial diagnosis, MBC patients had larger tumour diameters(P = 0.03) and fewer positive lymph nodes (P = 0.04). Patients with MBC were more likely to have organ metastases after surgery (P = 0.03). Despite receiving the same treatment, MBC patients had worse DFS (HR = 1.66, 95%CI 0.90-3.08, P = 0.11) and OS (HR = 1.98, 95% CI 1.03-3.81, P = 0.04), and OS was statistically significant. Positive lymph nodes at initial diagnosis were associated with worse DFS (HR = 3.98, 95%CI 1.05-15.12, P = 0.04) and OS (HR = 3.70, 95%CI 1.03-13.34, P = 0.04) for patients with MBC. The efficacy of platinum-based agents is insensitive for MBC patients receiving chemotherapy. In addition, patients treated with preoperative chemotherapy had worse DFS compared to patients treated with postoperative chemotherapy (HR = 3.51, 95%CI 1.05-11.75, P = 0.04).

CONCLUSIONS

The clinicopathological characteristics and prognosis of MBC and TN-IDC differ in many ways. Further studies are required to determine suitable treatment guidelines for patients with MBC.

Development and validation of competitive risk model for older women with metaplastic breast cancer

BACKGROUND

Metaplastic breast cancer (MpBC) is a rare histological subtype of breast cancer. This study aims to establish a competitive risk model for older women with MpBC to predict patients' survival accurately.

METHODS

Data on patients diagnosed with MpBC from 2010 to 2019 are from the Surveillance, Epidemiology and End Results (SEER) program in the United States. All patients were randomly assigned to the training set and validation set. The proportional sub-distribution risk model was used in the training set to analyze the risk factors affecting patient death. Based on the risk factors for cancer-specific mortality (CSM) in patients, we constructed a competitive risk model to predict patients' 1-, 3-, and 5-year cancer-specific survival. Then we used the concordance index (C-index), the calibration curve and the area under the receiver operating characteristic curve (AUC) to validate the discrimination and accuracy of the model.

RESULTS

One thousand, four hundred twelve older women with MpBC were included in this study. Age, T stage, N stage, M stage, tumor size, surgery and radiotherapy were risk factors for CSM. We established a competitive risk model to predict 1-, 3-, and 5-year cancer-specific survival in older women with MpBC. The C-index of the model was 0.792 in the training set and 0.744 in the validation set. The calibration curves in the training and validation sets showed that the model's predicted values were almost consistent with the actual observed values. The AUC results show that the prediction model has good accuracy.

CONCLUSION

We developed a competitive risk model based on these risk factors to predict cancer-specific survival in older women with MpBC. The validation results of the model show that it is a very effective and reliable prediction tool. This predictive tool allows doctors and patients to make individualized clinical decisions.

Metaplastic breast carcinoma: Analysis of clinical and pathologic features, a five-year study

Background

Metaplastic carcinoma breast (MCB) is a rare tumor comprising of both glandular and non-glandular patterns with epithelial and or mesenchymal components. Due to their varied clinicomorphological features, diagnosis has been challenging.

Aim

To study the clinicopathological and histomorphology of cases of metaplastic carcinoma breast diagnosed in a tertiary care hospital along with literature review.

Materials and Methods

This is a retrospective study including data of 11 patients who were diagnosed with MCB either on trucut or mastectomy specimens conducted between January 2014 and December 2018.

Results

The study includes 11 patients, out of which 10 were diagnosed on mastectomy while one on trucut specimen. All the patients were women with the mean age of presentation being 43.8 years. The most common presentation was palpable breast lump with mean tumor size of 7.3 cm in greatest dimension. Skin involvement was seen in 36.3% of cases. While eight cases (72.7%) were classified as epithelial, three (27.2%) were classified as mixed. Amongst epithelial variety, in eight cases, squamous component was seen along with infiltrating ductal carcinoma (IDC) while one was pure squamous type. In mixed variety, one case showed spindled areas along with squamous areas and areas of IDC. Other two showed focal sarcomatous and cartilaginous areas in one and angiosarcomatous, bone and cartilage formation admixed with areas of IDC in other case.

Conclusion

MCB are rare breast tumors with aggressive course and are characterized by their large size and rapid growth rate. Recently, there has been an upsurge in the cases of MCB due to increase in recognition of this entity. It has to be distinguished from other tumors by the pathologists so as to guide proper treatment.

Fibromatosis-like metaplastic carcinoma of the breast: Two case reports

BACKGROUND

Fibromatosis-like metaplastic carcinoma is classified as a rare type of metaplastic carcinoma of the breast by the 2012 WHO pathological and genetic classification criteria for breast tumors, which takes hyperplastic spindle cells as the main component and is often misdiagnosed as benign stromal proliferative lesions or benign mesenchymal tumors of the breast because of its mild morphology. Here, we collected the clinical data of 2 cases of fibromatosis-like metaplastic carcinoma of the breast and performed pathomorphological observation and immunohistochemical staining of the surgically resected specimens. According to the clinical features, imaging features, immunophenotype, diagnosis and differential diagnosis of 2 cases of fibromatosis-like metaplastic carcinoma of the breast, it was further differentiated.

CASE SUMMARY

Case 1: A 56-year-old postmenopausal female was admitted due to "right breast mass for over 1 year and local ulceration for over 1 mo". Physical examination showed a mass with a diameter of 4.5 cm × 5.5 cm palpable at 2.5 cm from the nipple at 1 o'clock in the right breast. The skin on the surface of the mass ruptured about 3 cm, with a small amount of exudation and bleeding, less clear boundary, hard texture, fair activity, without obvious tenderness. No obvious abnormality was palpable in the left breast. No enlarged lymph nodes were palpable in the bilateral axillae and bilateral supraclavicular region. After removing the mass tissue, it was promptly sent to the pathology department for examination. Case 2: Female, 52-years-old, premenopausal, admitted due to "right breast mass for more than 3 mo". Physical examination showed a 4.0 cm × 4.0 cm diameter mass palpable at 2.0 cm of the nipple in the lower outer 7 o'clock direction of the right breast, with less clear boundary, hard texture, fair activity, no significant tenderness, no palpable significant abnormalities in the left breast, and no palpable enlarged lymph nodes in the bilateral axillae and bilateral supraclavicular region. The mass was resected and sent for pathological examination. Postoperative pathological examination revealed fibromatosis-like metaplastic carcinoma of the breast in both patient 1 and patient 2. No systemic therapy and local radiotherapy were performed after surgery, and no tumor recurrence or metastasis was observed.

CONCLUSION

Fibromatosis-like metaplastic carcinoma of the breast is a rare subtype of metaplastic carcinoma that is often misdiagnosed, and the diagnosis relies on medical history collection, complete sampling, and full use of immunohistochemical assessment. The risk of lymph node and distant metastasis is low, and the current treatment is based on complete surgical resection. The efficacy of systemic radiotherapy and chemotherapy is not clear.

Metaplastic carcinoma of the breast: matched cohort analysis of recurrence and survival

PURPOSE

Metaplastic breast carcinoma (MBC) is a rare subtype of breast cancer, defined as mammary carcinoma with squamous or mesenchymal differentiation, that may include spindle cell, chondroid, osseous, or rhabdomyoid differentiation patterns. The implications of MBC recurrence and survival outcomes remains unclear.

METHODS

Cases were ascertained from a prospectively maintained institutional database of patients treated from 1998 to 2015. Patients with MBC were matched 1:1 to non-MBC cases. Cox proportional-hazards models and Kaplan-Meier estimates were used to evaluate outcome differences between cohorts.

RESULTS

111 patients with MBC were matched 1:1 with non-MBC patients from an initial set of 2400 patients. Median follow-up time was 8 years. Most patients with MBC received chemotherapy (88%) and radiotherapy (71%). On univariate competing risk regression, MBC was not associated with locoregional recurrence (HR = 1.08; p = 0.8), distant recurrence (HR = 1.65; p = 0.092); disease-free survival (HR = 1.52; p = 0.065), or overall survival (HR = 1.56; p = 0.1). Absolute differences were noted in 8-year disease-free survival (49.6% MBC vs 66.4% non-MBC) and overall survival (61.3% MBC vs 74.4% non-MBC), though neither of these reached statistical significance (p = 0.07 and 0.11, respectively).

CONCLUSION

Appropriately-treated MBC may exhibit recurrence and survival outcomes that are difficult to distinguish from those of non-MBC. While prior studies suggest that MBC has a worse natural history than non-MBC triple-negative breast cancer, prudent use of chemotherapy and radiotherapy may narrow these differences, although studies with more power will be required to inform clinical management. Longer follow-up among larger populations may further elucidate the clinical and therapeutic implications of MBC.

Dynamic contrast-enhanced MRI and sequential CT findings of metaplastic breast carcinoma in neurofibromatosis type 1: A case report

Metaplastic breast carcinoma in neurofibromatosis type 1 is extremely rare. There are few reports about dynamic contrast-enhanced MRI findings and sequential CT findings of metaplastic breast carcinoma in neurofibromatosis type 1. Herein, we report imaging findings, including dynamic contrast-enhanced MRI and sequential CT, of metaplastic breast carcinoma in an 82-year-old woman with neurofibromatosis type 1. Short tau inversion recovery image revealed an oval mass with a circumscribed margin that exhibited moderate intensity with partially hyperintense area inside, and T1-weighted imaging revealed a spotty hyperintense area. The solid component of the mass showed heterogeneous enhancement and the time-intensity curve had a fast/washout pattern with restricted diffusion. In addition, multiple neurofibromas were observed. Sequential CT revealed that the diameter of the mass doubled in 3 months without apparent lymph node metastasis. Because detection of metaplastic breast carcinoma in neurofibromatosis type 1 tends to be delayed due to multiple neurofibromas, characteristic MRI findings suggestive of metaplastic breast carcinoma and sequential CT findings are important for early treatment of metaplastic breast carcinoma in patients with neurofibromatosis type 1.

Metaplastic Breast Carcinoma in U.S. Population: Racial Disparities, Survival Benefit of Adjuvant Chemoradiation and Future Personalized Treatment with Genomic Landscape

PURPOSE

In this population-based study, we aim to identify factors that are influential on the survival outcome in MBC and investigate novel molecular approaches in personalized disease management.

METHODS

The data of this study were collected from the SEER database from 2000-2018. A total of 5315 cases were extracted from the database. The data were evaluated for demographics, tumor characteristics, metastasis, and treatment. Survival analysis was completed by using SAS software for multivariate analysis, univariate analysis, and non-parametric survival analysis. The molecular data with the most common mutations in MBC were extracted from the Catalogue of Somatic Mutations in Cancer (COSMIC) database.

RESULTS

The mean age at the time of presentation was 63.1 with a standard deviation (SD) of 14.2 years. Most patients were White (77.3%) with 15.7% Black patients, 6.1% Asian or Pacific Islander, and 0.5% American Indian. Histologically, most of the reported tumors were grade III (74.4%); 37% of the cases were triple negative (ER-, PR- and HER2-), whereas the hormone status was unknown in 46% of the cases. Spread was localized in 67.3% of patients while 26.3% had regional spread and 6.3% had distant metastases. Most tumors were unilateral (99.9%) and between 20-50 mm in size (50.6%). The lungs were the most common site for distant metastasis at diagnosis (3.42%) followed by bone (1.94%), liver (0.98%), and brain (0.56%). A combination of surgery, chemotherapy, and radiation therapy was the most common treatment with a cause-specific survival rate of 78.1% (95% CI = 75.4-80.4). The overall survival rate at 5 years was 63.6% (95% confidence interval (CI) = 62.0-65.1) with a cause-specific survival of 71.1% (95% CI = 69.5-72.6). Cause-specific survival was found to be 63.2% (95% CI = 58.9-67.1) in Black patients as compared to 72.4% (95% CI = 70.1-74.1) in White patients. Black patients also presented with higher rates of grade III disease, distant metastasis, and larger tumor size. On multivariate analysis, age > 60, grade III+, metastasis, and tumor size > 50 mm were associated with worse survival. The most common mutations in MBC identified in COSMIC data were TP53, PIK3CA, LRP1B, PTEN, and KMT2C.

CONCLUSION

Though rare, MBC is aggressive, with poor prognosis associated with high-grade tumors, metastasis, tumor size over 50 mm, and advanced age at the time of presentation. Overall, Black women had worse clinical outcomes. MBC is difficult to treat and carries a poor prognosis that affects various races disproportionately. Continued enhancement of treatment strategies to foster more individualized care as well as continued enrollment in clinical trials are needed to improve outcomes among patients with MBC.

Cavitary lung metastases of mixed metaplastic breast cancer mimicking aspergilloma

We report a case of a 57-year-old woman with pulmonary metastasis of breast cancer presenting with a characteristic cavitary shadow resembling aspergilloma. The primary tumor and metastases showed multiple histopathologic components, including squamous cell carcinoma. Although a fungal ball-like shadow may indicate the presence of a pulmonary aspergilloma, a comprehensive examination, including bronchoscopy, should be considered.

Metaplastic breast carcinoma: an overview of the radio-pathologic features in retrospective cohort tertiary hospital

Background

Metaplastic breast carcinoma (MBC) is a rare type of breast carcinoma. It accounts for 0.2–1% of all invasive breast carcinoma. The aim of this study is to investigate the radiological features of this tumor and correlate them with the pathological findings.

Results

Of the 22 patients with pathology-proven metaplastic cancers, 18 patients  (81.82%) presented with a palpable mass. The majority of the mammogram findings were masses with irregular shapes (n = 12, 63.16%) and indistinct margins (n = 11, 57.89%). Similarly, the majority of the ultrasound studies showed masses with irregular shapes (n = 16, 72.73%) and indistinct margins (n = 8, 36.36%). Most of the echopatterns were complex or with heterogeneous textures, each presented in eight cases (36.36%). More than half of the cases had a posterior acoustic enhancement (n = 12, 54.55%). Most of the cases tested negative for estrogen receptors, progesterone receptors and HER2 protein, and they were high-grade tumors with a high proliferative index (Ki-67%) of > 15%.

Conclusion

MBC is a rare and distinct aggressive breast cancer with no definite characteristic imaging compared to other breast cancer. It shows a mass with irregular shape and indistinct margins in both mammogram and ultrasound. Additionally, it reveals posterior acoustic enhancement and rarely contains microcalcifications. The correlation with the pathological findings is crucial for the diagnosis and subsequent appropriate treatment.

Metaplastic Breast Cancer: Characteristics and Survival Outcomes

Objectives

Metaplastic breast cancer (MBC) is a rare neoplasm accounting for <1% of all breast cancer. We evaluated the clinical characteristics and survival outcomes of MBC.

Methods

Patients diagnosed with pathologically proven MBC were reviewed from the institutional breast cancer database from 2000 to 2017.

Results

A total of 136 patients diagnosed with MBC were included in the study. The median age of the diagnosis was 60 years, and 60% of patients were stage II at diagnosis, and 22% were stage III. About two-thirds of the patients were triple-negative; 93% had nuclear grade III, and 25% had a lymphovascular invasion. Squamous differentiation (29%) was the most common histologic subtype, followed by the spindle subtype (21%). The most common distant metastases were lung (22%), followed by bone (13%). Moreover, 60% had a mastectomy, 19% had endocrine therapy, 58% had radiation, 51% received anthracycline-based chemotherapy, 26% had non-anthracycline chemotherapy, and 22% received no chemotherapy. In the entire cohort, the two-year overall survival (OS) and five-year OS were 79% and 69%, respectively, and the two-year progression-free survival (PFS) and five-year PFS were 72% and 61%, respectively. On multivariable analysis, the stage of MBC (stage III: hazard ratio (HR), 5.065 (95% confidence interval (CI), 1.02-25.27) (p=0.048)), poor functional status (Eastern Cooperative Oncology Group (ECOG) score, 2; HR, 24.736 (95% CI, 1.92-318.73) (p=0.014)), and distant metastasis to the brain (HR, 8.453 (95% CI, 1.88-38.04) (p=0.005)) and lung (HR, 42.102 (95% CI, 7.20-246.36) (p<0.001)) were significant predictors of decreased OS.

Conclusions

MBC demonstrated early disease progression and poor overall survival. The stage of MBC, decreased performance status, and metastasis to the lung and brain were independent poor prognostic factors.

Differences of Clinicopathological Features between Metaplastic Breast Carcinoma and Nonspecific Invasive Breast Carcinoma and Prognostic Profile of Metaplastic Breast Carcinoma

Introduction

Metaplastic breast carcinoma is a rare special type of breast cancer, which has distinguished clinical characteristics. We aimed to evaluate the clinicopathological features of metaplastic breast carcinoma compared with nonspecific invasive breast carcinoma and study the prognosis of metaplastic breast carcinoma.

Methods

We reviewed metaplastic breast carcinoma cases (n = 37) from January 2000 to December 2021 and nonspecific invasive breast carcinoma cases (n = 433) from January 2019 to December 2020 extracted from our institution retrospectively. The following variables were recorded, including the patients' general information, complications, T stage, expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, Ki-67, molecular subtyping, lymph node status, skin or chest wall involvement, vessel carcinoma embolus, therapy modality (surgical treatments, chemotherapy, and radiotherapy), and survival.

Results

Patients with metaplastic breast carcinoma had more advanced disease than patients with nonspecific invasive breast carcinoma (T stage: P=0.0011). A greater proportion of metaplastic breast carcinoma presented with triple-negative breast cancer than nonspecific invasive breast carcinoma (79.41% vs. 12.47%, P ≤ 0.001). Our study showed that the skin or chest wall invasion was more frequent in metaplastic breast carcinoma patients (11.76% vs. 1.62%, P=0.005). The 5-year survival rate for metaplastic breast carcinoma patients was 57.66% (95% CI: 0.3195∼0.7667). No local recurrence was observed while distant metastasis occurred in 33.33% of patients with metaplastic breast carcinoma. Death due to disease occurred in 24.24% of patients with metaplastic breast carcinoma.

Conclusion

The majority of metaplastic breast carcinoma patients had more advanced disease and triple-negative disease than nonspecific invasive breast carcinoma patients. Also, metaplastic breast carcinoma patients had frequent skin or chest wall invasion and a high rate of distant metastasis and mortality.

The different outcomes between breast-conserving surgery plus radiotherapy and mastectomy in metaplastic breast cancer: A population-based study

Background

Metaplastic breast cancer (MBC) are rare. The survival outcomes of MBC patients after breast conserving surgery plus radiotherapy (BCS+RT) or mastectomy have not been established. The study aimed to compare survival outcomes of MBC patients subjected to BCS+RT or mastectomy therapeutic options.

Methods

Patients who were subjected to BCS+RT or mastectomy between 2004 and 2014 were enrolled in this study through the Surveillance, Epidemiology and End Results (SEER) database. Breast cancer-specific survival (BCSS) and the overall survival (OS) of the participants were determined. Cox proportional hazard model and the Kaplan Meier method were used to determine the correlation between the two surgical methods and survival outcomes.

Results

A total of 1197 patients were enrolled in this study. Among them, 439 patients were subjected to BCS+RT, while 758 patients were subjected to mastectomy. After propensity score matching (PSM), the BCS+RT and mastectomy groups consisted of 321 patients, respectively. The univariate and multivariate analysis with a 6-month landmark all indicate that patients receiving BCS+RT has higher OS than patients receiving mastectomy (HR = 0.701,95% CI = 0.496–0.990, P = 0.044; HR = 0.684,95% CI = 0.479–0.977, P = 0.037) while the BCSS was no difference between the two groups (HR = 0.739,95% CI = 0.474–1.153, P = 0.183; HR = 0.741,95% CI = 0.468–1.173, P = 0.200).

Conclusion

The BCS+RT therapeutic option exhibits a higher OS in MBC patients compared to the mastectomy approach.

Metaplastic carcinoma of the breast: Clinicopathological features and treatment outcomes with long-term follow up

Metaplastic breast carcinoma is an uncommon subtype of invasive ductal carcinoma with a tendency towards poorer clinical outcomes. Following ethical approval, the current study reviewed the institutional records of ~2,500 women with breast cancer. A total of 14 cases of metaplastic breast cancer were reviewed for management and treatment outcomes. The results demonstrated that patients had median follow up of 30 months, a 5-year disease-free survival of 57.1% and 5-year overall survival of 57.1%. The majority of patients had at least T2 disease and all tumours were high grade. Additionally, most patients were triple negative and nodal metastases were uncommon. Metaplastic breast cancer is an aggressive variant of invasive breast cancer. Most patients can be treated with breast conservation and survival parameters tend to be worse than more common breast cancer subtypes.

GATA binding protein 3 (GATA3) as a marker for metaplastic spindle cell carcinoma of the breast

Spindle cell lesions of the breast comprise a diverse set of tumors; harboring significant histological and immunohistochemical (IHC) overlap. Accurate diagnosis and classification of spindle cell lesions in the breast remains challenging, especially in core biopsies. In the current study, we evaluated a spectrum of spindle cell lesion of the breast with a panel of IHC antibodies in an effort to differentiate metaplastic spindle cell carcinoma from its benign and malignant mimickers. Our study included 92 patients who underwent breast core biopsies or breast resections at Northwell Health who were diagnosed with benign and malignant tumor/tumor-like spindle cell lesions. Tumors subtypes in this the study included: angiosarcoma, nodular fasciitis, fibromatosis, myofibroblastoma, phyllodes tumors (benign, borderline and malignant), primary sarcomas and metaplastic spindle cell carcinoma. Our biomarker panel included high molecular weight keratin (HMWK), CAM5.2, AE1/AE3, p63, CD34 and GATA3. GATA3 expression was significantly higher in metaplastic carcinomas (88.9 % vs 4.1 %, p < 0.001), when compared to other spindle cell lesions. The sensitivity and specificity for detecting metaplastic carcinomas reached 84.2 % and 97.3 %, respectively. Regarding cytokeratin panels, none of the three individual markers were as sensitive or specific for metaplastic breast carcinoma. GATA3 is the most specific and sensitive marker forfor the identification of metaplastic spindle cell carcinoma of the breast.

Metaplastic breast cancer: Treatment and prognosis by molecular subtype

BACKGROUND

Metaplastic breast cancer (MBC) is a rare and aggressive subtype of breast. However, the effect of molecular subtype on treatment and prognosis of MBC remains unclear.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results database was used to analyze patients with MBC between 2010 and 2016. Molecular subtype was stratified to TN group (ER and PR-/HER2-), HER2 group (ER and PR-/HER2+, ER/PR+ and HER2+), and HR group (ER/PR+ and HER2-). The breast cancer-specific survival (BCSS) differences were estimated using multivariate Cox regression model and Kaplan-Meier curves.

RESULTS

We included 1665 patients with median follow-up time of 27 months (range 0-83 months). 1154 (69.3%), 65 (3.9%), and 446 (26.8%) patients presented in TN group, HER2 group, and HR group, respectively. On multivariate Cox analysis, the prognosis was related to age, tumor size, regional node metastasis, and surgery. Molecular subtype remained no impact on BCSS. Radiotherapy (RT) was associated with better prognosis. Patients cannot benefit from chemotherapy. In Kaplan-Meier curve, triple-negative (P = 0.047) and HR-positive (P = 0.006) patients receiving RT had a superior BCSS than that not RT. HER2-positive patients cannot benefit from RT. However, adjusted Kaplan-Meier survival model showed that triple-negative (P = 0.019) but not HER2-positive (P = 0.575) or HR-positive (P = 0.574) patients receiving RT had a superior BCSS than that not RT.

CONCLUSIONS

Molecular subtype is not associated with the better prognosis of MBC. Patients could benefit from RT. However, triple-negative but not HR-positive or HER2-positive patients have superior survival after receiving RT.

Metaplastic breast cancer: an old histotype but a current therapeutic problem

Metaplastic breast cancer (MPBC) is a rare and aggressive tumor type in great need of satisfactory therapies. Although most cases of MPBC are 'triple negative', they are nonetheless related to worse outcomes compared with other triple-negative invasive tumors. MPBC presents high levels of genetic and molecular heterogeneity, suggesting that novel targeted therapies can be exploited. Overexpression of PD-L1 and high levels of tumor-infiltrating lymphocytes have also been observed in these tumors, suggesting a role for immunotherapy. We present an updated literature revision on clinical, histopathological and molecular features of MPBC and their significance to prognosis and therapy options. We discuss emerging efforts to improve and personalize prognostic and therapeutic approaches, exploiting the molecular signature of MPBC with targeted therapies and immunotherapies.

Research on the Role of Combined Chemotherapy and Radiotherapy in Patients With N+ Non-Metastatic Metaplastic Breast Carcinoma: A Competing Risk Analysis Model Based on the SEER database, 2000 to 2015

Purpose

Due to the rarity of metaplastic breast carcinoma (MpBC), no randomized trials have investigated the role of combined chemotherapy and radiotherapy (CCRP) in this condition. We aimed to explore and identify the effectiveness of CCRP in patients with regional lymph node metastasis (N+) non-metastatic MpBC.

Materials and Methods

Data were obtained from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program database. We assessed the effects of CCRP on overall survival (OS), breast cancer-specific survival (BCSS), and breast cancer-specific death (BCSD) using Kaplan-Meier analysis, competing risk model analysis, and competing risk regression mode analysis.

Results

A total of 707 women and 361 death cases were included in the unmatched cohort, of which 76.45% (276/361) were BCSD, and 23.55% (85/361) were non-breast cancer-specific deaths (non-BCSD). Both the ChemT and CCRP groups had better OS (ChemT group: HR: 0.59, 95% CI: 0.45–0.78, P<0.001; CCRP group: HR: 0.31, 95% CI: 0.23–0.41, P<0.001) and BCSS (ChemT group: HR: 0.63, 95% CI: 0.45–0.87, P<0.001; CCRP group: HR: 0.32, 95%CI: 0.22–0.46, P<0.001) than the non-therapy group. Subjects in the CCRP group tended to have significantly lower cumulative BCSD (Gray’s test, P=0.001) and non-BCSD (Gray’s test, P<0.001) than the non-therapy group or ChemT group. In competing risk regression model analysis, subjects in the CCRP group had a better prognosis in BCSD (HR: 0.710, 95% CI: 0.508–0.993, P=0.045) rather than the ChemT group (HR: 1.081, 95% CI: 0.761–1.535, P=0.660) than the non-therapy group.

Conclusion

Our study demonstrated that CCRP could significantly decrease the risk of death for both BCSD and non-BCSD and provided a valid therapeutic strategy for patients with N+ non-metastatic MpBC.

The longitudinal risk of mortality between invasive ductal carcinoma and metaplastic breast carcinoma

The management of metaplastic breast carcinoma (MBC) has largely paralleled the paradigms used for invasive ductal carcinoma (IDC) in the current National Comprehensive Cancer Network guidelines of breast cancer. However, patients with IDC and MBC have been shown to have a different prognosis, and there are significant differences in risk and failure patterns after treatment. The purpose of this study was to compare breast cancer specific survival (BCSS) and hazard function between IDC and MBC. We included patients from the Surveillance, Epidemiology, and End Results program with stage I-III IDC and MBC between 2000 and 2012. Statistical analyses were including chi-square analysis, life-table methods, multivariate Cox proportional hazards models, and propensity score matching (PSM). We identified 294,719 patients; 293,199 patients with IDC and 1520 patients with MBC. Multivariate analyses showed that the MBC subtype had significantly lower BCSS than the IDC subtype before and after PSM (p < 0.001). There were significant differences in the hazard curve between IDC and MBC. The hazard curve for breast cancer mortality in the IDC cohort peaked at 3 years (2%), and then changed to a slowly decreasing plateau after prolonged follow up. However, the hazard curve for breast cancer mortality in the MBC cohort peaked at 2 years (7%), then declined sharply between 3 and 6 years, and changed to a low death rate after a follow-up time exceeding 6 years. Subgroup analyses revealed that the hazard curves significantly differed between IDC and MBC after stratifying by tumor stage and hormone receptor status. Our study suggests that patients with MBC should receive more effective systemic agents and intensive follow-up because of their significantly augmented risk of death compared to IDC patients.

Subcellular localization of EZH2 phosphorylated at T367 stratifies metaplastic breast carcinoma subtypes

BACKGROUND

Metaplastic carcinoma is an aggressive, triple-negative breast cancer (TNBC) with differentiation towards squamous, spindle, or mesenchymal cell types. The molecular underpinnings of the histological subtypes are unclear. Our lab discovered a cytoplasmic function of EZH2, a transcriptional repressor, whereby pEZH2 T367 binds to cytoplasmic proteins in TNBC cells and enhances invasion and metastasis. Here, we investigated the expression and subcellular localization of pEZH2 T367 protein in metaplastic carcinomas.

METHODS

Thirty-five metaplastic carcinomas (17 squamous, 10 mesenchymal, and 8 spindle) were evaluated and immunostained with anti-pEZH2 T367. We analyzed staining intensity (score 1-4), subcellular localization (nuclear/cytoplasmic), and localization within the tumor (center/invasive edge). Protein expression of pEZH2 T367-binding partners was measured from a quantitative multiplex proteomics analysis performed in our lab.

RESULTS

Cytoplasmic pEZH2 T367 was significantly upregulated in squamous (14 of 17, 82%) compared to mesenchymal (4 of 10, 40%) and spindle (2 of 6, 33%) subtypes (p = 0.011). Twenty-five of 34 (73%) tumors with available tumor-normal interface showed accentuated cytoplasmic pEZH2 T367 at the infiltrative edge. Cytoplasmic pEZH2 T367 was upregulated in 9 of 10 (90%) tumors with lymph node metastasis (p = 0.05). Bioinformatics analyses identified an EZH2 protein network in metaplastic carcinomas (p value: < 1.0e-16). Using quantitative proteomics, we found significantly increased expression of cytoplasmic EZH2-binding partners in squamous compared to spindle and mesenchymal subtypes.

CONCLUSIONS

pEZH2 T367 expression and subcellular localization may be useful to distinguish metaplastic carcinoma subtypes. pEZH2 T367 may play a role in the histological diversity and behavior of these tumors.

A Case of Squamous Cell Carcinoma of the Breast with Low-Grade Adenosquamous Carcinoma

A 68-year-old woman with a breast mass was referred to our hospital. Imaging studies showed an oval well-defined mass, 1.3 cm in size, in her left lower outer quadrant of the breast. Core needle biopsy with immunohistochemical staining showed atypical spindle cells forming solid nests with necrosis and papillary lesions, leading to the tentative and pre-operative diagnosis of invasive ductal carcinoma. Due to the absence of daughter nodules, extensive ductal spread, and lymphadenopathy on imaging evaluation, the patient underwent breast-conserving surgery and sentinel node biopsy, resulting in negative surgical margins and no lymph node involvement. Post-operative pathological examination showed triple negative atypical cells with squamous differentiation, squamous cell carcinoma (SCC), with cystic parts and a small amount of low-grade adenosquamous cell carcinoma (LGASC), both encompassing the cystic parts in a contiguous fashion. No cases with synchronous SCC and LGASC in the breast have been reported to date. An etiologic correlation between SCC and LGASC should be further evaluated.

Descriptive study of the histopathological subtypes and programmed death-ligand 1 in metaplastic breast carcinoma

Metaplastic Breast Carcinoma (MBC) is a rare heterogeneous group of tumors, the incidence of which is less than 1% of breast tumors. These are a unique set of tumors with varying subtypes, poor prognosis, and an increased chance of distant metastasis. We aimed to study the clinical, histomorphological, and immunohistochemical (IHC) features of Metaplastic Breast Carcinoma (MBC). This was a descriptive study of cases diagnosed as MBC at a tertiary care center in Southern India from January 2015 to December 2019. A total of 20 cases were diagnosed whose clinical, histomorphological, and IHC features were studied. PD-L1and CD8 IHC were performed and analyzed in 12 cases. The median age of presentation was 50 years. Seventy percent (14/20) patients were postmenopausal women. On excision, 75% (15/20) showed mixed typed MBC, the remainder showing epithelial type MBC. Metastasis to axillary lymph node was seen only in 20% (4/20) of the cases. Thirty percent (6/20) of the cases belonged to stage 3 disease and 5% (1/20) of the cases belonged to stage 4 disease with liver metastasis. Estrogen receptor (ER), Progesterone receptor (PR) were negative in all the cases, Her2neu was positive in three cases. Ki67 labeling index was greater than 14% in all the cases. PD-L1was positive in 41.5% of the cases and intratumoral CD8 positive lymphocytes were increased in 83.3% of the cases. MBCs are tumors occurring in elderly postmenopausal women, presenting with large tumor size, have lesser chances of lymph node metastasis, and a higher chance of recurrence and hematogenous spread. They are negative for ER, PR, Her-2 neu, with a high Ki67 index and a strong PDL-1 expression.

Metaplastic Carcinoma of the Breast with Squamous Differentiation: A Case Report from the University Teaching Hospital of Kigali (CHUK), Rwanda

Metaplastic breast carcinoma is a rare and aggressive condition, accounting less than 1% of breast malignancies. It presents with large mass and frequently with distant metastasis at time of diagnosis. Morphologically, it is characterized by the differentiation of neoplastic epithelium into epithelial or mesenchymal-looking elements like squamous cells, spindle cells, cartilage, or bone and has poor prognosis with its triple negative status.

Core needle biopsy diagnosis of fibroepithelial lesions of the breast: a diagnostic challenge

Fibroepithelial lesions (FEL) of the breast are biphasic neoplasms consisting of proliferative epithelial and stromal components and include fibroadenoma, phyllodes tumour and periductal stromal tumour. Core needle biopsy (CNB) is a commonly used diagnostic modality for investigation of breast lesions. As the accurate diagnosis of FEL requires integrated assessment of both epithelial and stromal components, this may create problems in small biopsies with limited sampling. In this review, common problems encountered in CNB of FEL are discussed, including establishing a diagnosis of borderline/malignant phyllodes tumour in a biopsy consisting of malignant spindle cells, differentiating phyllodes tumour from fibroadenoma on CNB, grading of phyllodes tumour of intermediate histological grade and assessment of periductal stromal tumours. The approaches are detailed systematically based on histology, immunohistochemistry and molecular characterisation. This comprehensive approach may aid in dealing with the overlapping histological appearance of FEL and sampling limitations of CNB.

Synchronous metaplastic breast carcinoma and lung adenocarcinoma: a rare case and review of the literature

Synchronous primary cancers occur in 1.7% of breast cancer cases and metaplastic breast cancer (MBC) occurs in less than 1% of breast cancer cases. We present a previously healthy 66-year-old woman diagnosed with MBC after surgical resection of a presumed cyst. A second primary cancer, multifocal lung adenocarcinoma, was discovered during the staging process for her MBC. Remarkably she had not experienced pulmonary or constitutional symptoms at the time of diagnosis. She received chemotherapy with paclitaxel and carboplatin, followed by immunotherapy with nivolumab. At 24 months of follow-up after her initial diagnosis, she was breast cancer-free with stable pulmonary nodules. This case highlights that rather than assuming multifocal lesions represent metastasis, biopsies should be considered as clinical management could be significantly altered in the presence of a synchronous cancer. Furthermore, platinum-based chemotherapy agents have potential to be considered in the treatment of MBC.

Dermatofibrosarcoma protuberans - the use of neoadjuvant imatinib for treatment of an uncommon breast malignancy: a case report

BACKGROUND

Dermatofibrosarcoma protuberans is a rare soft tissue malignancy that, if left untreated, can be locally destructive and life-threatening. Dermatofibrosarcoma protuberans is uncommon in the breast, and the similarity of its morphologic features with other spindle cell malignancies can make correct identification difficult. Immunohistochemistry and molecular testing can aid in the correct diagnosis when there is diagnostic uncertainty. Imatinib, a selective tyrosine kinase inhibitor, has been used for adjuvant treatment of dermatofibrosarcoma protuberans following surgical resection. When used as a neoadjuvant treatment, imatinib offers the opportunity to decrease tumor size prior to surgery to lessen the chance for disfigurement.

CASE PRESENTATION

We present the case of a Caucasian woman who was 46-year-old when she first noted a mass in her right breast in 2015; she was initially diagnosed as having metaplastic breast carcinoma. Mastectomy and systemic chemotherapy were planned; however, after review of pathology at a referral center, the diagnosis was changed to dermatofibrosarcoma protuberans. She was treated with 4 months of neoadjuvant imatinib with adequate tumor shrinkage to perform breast conservation.

CONCLUSION

This patient's case stresses the importance of correctly diagnosing this rare breast tumor through the histopathologic appearance of dermatofibrosarcoma protuberans, molecular pathogenesis, and immunohistochemistry. These techniques can help differentiate dermatofibrosarcoma protuberans from metaplastic breast carcinoma and other spindle cell lesions of the breast. This is critical, as the treatment options for metaplastic breast carcinoma significantly differ from treatment options for dermatofibrosarcoma protuberans. This case describes the use of imatinib as a neoadjuvant option to reduce preoperative tumor size and improve surgical outcomes.

A Novel 3D Scaffold for Cell Growth to Asses Electroporation Efficacy

Tumor electroporation (EP) refers to the permeabilization of the cell membrane by means of short electric pulses thus allowing the potentiation of chemotherapeutic drugs. Standard plate adhesion 2D cell cultures can simulate the in vivo environment only partially due to lack of cell–cell interaction and extracellular matrix (ECM). In this study, we assessed a novel 3D scaffold for cell cultures based on hyaluronic acid and ionic-complementary self-assembling peptides (SAPs), by studying the growth patterns of two different breast carcinoma cell lines (HCC1569 and MDA-MB231). This 3D scaffold modulates cell shape and induces extracellular matrix deposit around cells. In the MDA-MB 231 cell line, it allows three-dimensional growth of structures known as spheroids, while in HCC1569 it achieves a cell organization similar to that observed in vivo. Interestingly, we were able to visualize the electroporation effect on the cells seeded in the new scaffold by means of standard propidium iodide assay and fluorescence microscopy. Thanks to the presence of cell–cell and cell–ECM interactions, the new 3D scaffold may represent a more reliable support for EP studies than 2D cancer cell cultures and may be used to test new EP-delivered drugs and novel EP protocols.

The role of radiotherapy in metaplastic breast cancer: a propensity score-matched analysis of the SEER database

BACKGROUND

Only few studies, with small patient cohorts, have evaluated the effect of radiotherapy (RT) for metaplastic breast cancer (MBC). Hence, it is important to investigate the role of RT in MBC survival using a large population-database.

METHODS

A retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) from 1973 to 2015 was performed. We compared MBC patients with or without RT for overall survival (OS) and breast cancer-specific survival (BCSS) using univariate and multivariate Cox proportional hazard regressions before and after propensity score matching (PSM).

RESULTS

From a total of 2267 patients diagnosed with MBC between 1998 and 2015, 1086 (47.9%) received RT. In the multivariate analysis before PSM, RT provided a better OS (HR 0.73; 95% CI 0.61-0.88; p = 0.001) and BCSS (HR 0.71; 95% CI 0.58-0.88; p = 0.002). Multivariate analyses after PSM (n = 1066) confirmed that patients receiving RT (n = 506) survived longer than those without RT (OS, HR 0.64; 95% CI 0.51-0.80; p < 0.001 and BCSS, HR 0.64; 95% CI 0.50-0.83; p = 0.001). A longer OS was observed when RT was given to older patients (p = 0.001) and in case of large tumor size (p = 0.002). Intriguingly, patients with N0 stage showed better OS after RT (HR 0.69, P = 0.012).

CONCLUSIONS

Our findings support the beneficial effect of RT for MBC patients. In particular, older patients or with large tumor size have a greater survival benefit from RT. In conclusion, we have assessed the importance of the use of RT in MBC as survival factor and this could lead to the development of guidelines for this rare sub-type of tumors.

Pathway activity profiling of growth factor receptor network and stemness pathways differentiates metaplastic breast cancer histological subtypes

BACKGROUND

Gene expression profiling of rare cancers has proven challenging due to limited access to patient materials and requirement of intact, non-degraded RNA for next-generation sequencing. We customized a gene expression panel compatible with degraded RNA from formalin-fixed, paraffin-embedded (FFPE) patient cancer samples and investigated its utility in pathway activity profiling in patients with metaplastic breast cancer (MpBC).

METHODS

Activity of various biological pathways was profiled in samples from nineteen patients with MpBC and 8 patients with invasive ductal carcinoma with triple negative breast cancer (TNBC) phenotype using a custom gene expression-based assay of 345 genes.

RESULTS

MpBC samples of mesenchymal (chondroid and/or osteoid) histology demonstrated increased SNAI1 and BCL2L11 pathway activity compared to samples with non-mesenchymal histology. Additionally, late cornified envelope and keratinization genes were downregulated in MpBC compared to TNBC, and epithelial-to-mesenchymal transition (EMT) and collagen genes were upregulated in MpBC. Patients with high activity of an invasiveness gene expression signature, as well as high expression of the mesenchymal marker and extracellular matrix glycoprotein gene SPARC, experienced worse outcomes than those with low invasiveness activity and low SPARC expression.

CONCLUSIONS

This study demonstrates the utility of gene expression profiling of metaplastic breast cancer FFPE samples with a custom counts-based assay. Gene expression patterns identified by this assay suggest that, although often histologically triple negative, patients with MpBC have distinct pathway activation compared to patients with invasive ductal TNBC. Incorporation of targeted therapies may lead to improved outcome for MpBC patients, especially in those patients expressing increased activity of invasiveness pathways.

Metaplastic breast carcinoma: Current therapeutic approaches and novel targeted therapies

Metaplastic breast carcinoma (MBC) is a rare subtype of invasive breast cancer consisting of various combinations of malignant epithelial and mesenchymal cells. Its aggressive growth pattern combined with its histological heterogeneity account for MBC's characteristic resistance to systemic therapies, which subsequently leads to increased risk of recurrence and breast cancer mortality compared with other invasive mammary carcinomas. The aim of this review is to discuss the current therapeutic approaches, both in loco-regional as well as in systemic management of MBC. With the accumulation of knowledge from histopathologic assessment and the increasing identification of underlying molecular aberrations, emerging, novel targeted therapies will enable physicians to implement a more individualized and efficacious therapeutic strategy, leading hopefully to an improvement in the poor prognosis of MBC.

Prognosis in different subtypes of metaplastic breast cancer: a population-based analysis

BACKGROUND

Metaplastic breast cancer (MpBC) is a rare histological subtype of breast cancer recognized as a unique pathologic entity in 2000. However, the pathogenesis, optimal therapy, and prognosis of MpBC and the potential effect of systemic treatments on different subtypes of MpBC are not well defined.

METHODS

A retrospective population-based study was performed to identify breast cancer patients with MpBC and other triple-negative breast cancers (TNBC) between 2010 and 2014 using the surveillance, Epidemiology, and End Results (SEER) database. Chi-square test was used to analyze characteristics between subgroups. Kaplan-Meier analysis and Multivariate Cox regressions were used to evaluate overall survival (OS) of MpBC, TNBC, and MpBC subgroups. Competing risk analysis and multivariate regression model of competing risk were used to assess breast cancer-specific survival (BCSS) of MpBC and TNBC RESULTS: We identified a study cohort of 22,433 patients (1112 MpBC and 21,321 TNBC). MpBC correlated with older population, larger tumor size and less lymph node involvement, and TNBC phenotype. Patients with MpBC especially with triple-negative subtype (TN-MpBC) had worse survival than the overall TNBC population. However, the prognosis of MpBC without triple-negative subtype (non-TN MpBC) was not different from that of TNBC. In Kaplan-Meier analysis, chemotherapy was not associated with significant difference in OS of TN-MpBC. In non-TN MpBC group, the 3-year OS was 79.8% for patients receiving chemotherapy and 70.5% in patients without chemotherapy, and chemotherapy was associated (P = 0.033) with improved OS. Within the MpBC patients, radiotherapy was significantly (HR 1.544; 95% CI 1.148-2.078; P = 0.004) associated with improved OS and (HR 1.474; 95% CI 1.067-2.040; P = 0.019) BCSS.

CONCLUSIONS

Patients with TN-MpBC had worse prognosis than TNBC and chemotherapy was not associated with improved survival. In contrast, non-TN MpBC may derive survival benefit from chemotherapy and radiotherapy.

Metaplastic carcinoma of the breast with mesenchymal differentiation (carcinosarcoma). A unique presentation of an aggressive malignancy and literature review

Metaplastic carcinoma of the breast with mesenchymal differentiation (MCMD), previously known as carcinosarcoma, is a very rare and aggressive tumor that has been recently classified as a subtype of metaplastic breast carcinoma. It accounts for 0.08%-0.2% of all breast cancers, with only a few cases reported in the literature. Histologically, MCMD is characterized by a biphasic pattern of malignant epithelial and sarcomatous components without evidence of a transition zone between the two elements. We herein describe a unique case of metaplastic carcinoma of the breast with chondrosarcomatous differentiation in a postmenopausal woman who presented with a large, rapidly growing, ulcerated, bleeding mass and signs of impending sepsis. Metaplastic breast carcinomas (MBC) are rare and aggressive tumors. They are characterized by larger size, lower rates of axillary node involvement, higher rates of triple negativity and distal metastases, earlier local recurrence and poorer survival compared with classic invasive breast cancer. Because of the rarity of MBC, the optimal treatment has not been well defined. Surgery is the main curative treatment modality since MBC has shown a suboptimal response to standard chemotherapy. Patients with MBC may be appropriate candidates for novel targeted therapies.

TiHo-0906: a new feline mammary cancer cell line with molecular, morphological, and immunocytological characteristics of epithelial to mesenchymal transition

Feline mammary carcinomas (FMCs) with anaplastic and malignant spindle cells histologically resemble the human metaplastic breast carcinoma (hMBC), spindle-cell subtype. hMBCs display epithelial-to-mesenchymal transition (EMT) characteristics. Herein we report the establishment and characterization of a cell line (TiHoCMglAdcar0906; TiHo-0906) exhibiting EMT-like properties derived from an FMC with anaplastic and malignant spindle cells. Copy-number variations (CNVs) by next-generation sequencing and immunohistochemical characteristics of the cell line and the tumour were compared. The absolute qPCR expression of EMT-related markers HMGA2 and CD44 was determined. The growth, migration, and sensitivity to doxorubicin were assessed. TiHo-0906 CNVs affect several genomic regions harbouring known EMT-, breast cancer-, and hMBCs-associated genes as AKT1, GATA3, CCND2, CDK4, ZEB1, KRAS, HMGA2, ESRP1, MTDH, YWHAZ, and MYC. Most of them were located in amplified regions of feline chromosomes (FCAs) B4 and F2. TiHo-0906 cells displayed an epithelial/mesenchymal phenotype, and high HMGA2 and CD44 expression. Growth and migration remained comparable during subculturing. Low-passaged cells were two-fold more resistant to doxorubicin than high-passaged cells (IC50: 99.97 nM, and 41.22 nM, respectively). The TiHo-0906 cell line was derived from a poorly differentiated cellular subpopulation of the tumour consistently displaying EMT traits. The cell line presents excellent opportunities for studying EMT on FMCs.

A polymorphism in the lysyl oxidase propeptide domain accelerates carcinogen-induced cancer

The propeptide (LOX-PP) domain of the lysyl oxidase proenzyme was shown to inhibit the transformed phenotype of breast, lung and pancreatic cells in culture and the formation of Her2/neu-driven breast cancer in a xenograft model. A single nucleotide polymorphism (SNP, rs1800449) positioned in a highly conserved region of LOX-PP results in an Arg158Gln substitution (humans). This arginine (Arg)→glutamine (Gln) substitution profoundly impaired the ability of LOX-PP to inhibit the invasive phenotype and xenograft tumor formation. To study the effect of the SNP in vivo, here we established a knock in (KI) mouse line (LOX-PPGln mice) expressing an Arg152Gln substitution corresponding to the human Arg158Gln polymorphism. Breast cancer was induced in wild-type (WT) and LOX-PPGln female mice beginning at 6 weeks of age by treatment with 7,12-dimethylbenz(a)anthracene (DMBA) in combination with progesterone. Time course analysis of tumor development demonstrated earlier tumor onset and shorter overall survival in LOX-PPGln versus WT mice. To further compare the tumor burden in WT and LOX-PPGln mice, inguinal mammary glands from both groups of mice were examined for microscopic lesion formation. LOX-PPGln glands contained more lesions (9.6 versus 6.9 lesions/#4 bilateral). In addition, more DMBA-treated LOX-PPGln mice had increased leukocyte infiltrations in their livers and were moribund compared with DMBA-treated WT mice. Thus, these data indicate that the Arg→Gln substitution in LOX-PP could be an important marker associated with a more aggressive cancer phenotype and that this KI model is ideal for further mechanistic studies regarding the tumor suppressor function of LOX-PP.

Carcinosarcoma (Metaplastic Carcinoma) Breast: A Rare and Aggressive Primary – Report of Two Cases with Review of Literature

Carcinosarcoma (CS) also known as metaplastic carcinoma of the breast is a rare and aggressive type of malignancy with controversial origin. Currently, there are no standard treatment guidelines outlined, owing to the rarity of the disease, but according to the available literature, surgery followed by adjuvant radiation therapy has the greatest benefit. We are presenting two cases of CS of breast developing metastasis. One of the cases presented with lung metastasis during the course of follow-up and responded significantly to chemotherapy, and the other is currently receiving chemotherapy. The cases are being presented here along with the literature review enlightening the current knowledge and available treatment options.

Unusual Breast Neoplasm with Diagnostic and Management Challenges

With the growing awareness and availability of proper screening methods, detection of breast lump is increasing globally and is now a very sensitive issue for females. The treatment of these lumps ranges from lumpectomy to wide local excision to mastectomy; hence, a proper diagnosis is very important to prevent under- or overtreatment in patients. Breast lesions are the heterogeneous diseases encompassing several distinct entities with remarkably different characteristics. While the more common forms of breast cancers are well recognized and understood better, there are many important unusual lesions and malignancies that are less known and less appreciated and can be challenging to diagnose. In such cases, due to rarity of the disease and lack of adequate treatment protocol, managing the patients can be a challenging task for surgeons and oncologist as well. In this article, we have shared our institutional experience in unusual breast lesions with emphasis on diagnostic as well as management challenges faced.

A Soft Microenvironment Protects from Failure of Midbody Abscission and Multinucleation Downstream of the EMT-Promoting Transcription Factor Snail

Multinucleation is found in more than one third of tumors and is linked to increased tolerance for mutation, resistance to chemotherapy, and invasive potential. The integrity of the genome depends on proper execution of the cell cycle, which can be altered through mechanotransduction pathways as the tumor microenvironment stiffens during tumorigenesis. Here, we show that signaling downstream of matrix metalloproteinase-3 (MMP3) or TGFβ, known inducers of epithelial-mesenchymal transition (EMT), also promotes multinucleation in stiff microenvironments through Snail-dependent expression of the filament-forming protein septin-6, resulting in midbody persistence, abscission failure, and multinucleation. Consistently, we observed elevated expression of Snail and septin-6 as well as multinucleation in a human patient sample of metaplastic carcinoma of the breast, a rare classification characterized by deposition of collagen fibers and active EMT. In contrast, a soft microenvironment protected mammary epithelial cells from becoming multinucleated by preventing Snail-induced upregulation of septin-6. Our data suggest that tissue stiffening during tumorigenesis synergizes with oncogenic signaling to promote genomic abnormalities that drive cancer progression.Significance: These findings reveal tissue stiffening during tumorigenesis synergizes with oncogenic signaling to promote genomic abnormalities that drive cancer progression. Cancer Res; 78(9); 2277-89. ©2018 AACR.

A murine preclinical syngeneic transplantation model for breast cancer precision medicine

We previously demonstrated that altered activity of lysophosphatidic acid in murine mammary glands promotes tumorigenesis. We have now established and characterized a heterogeneous collection of mouse-derived syngeneic transplants (MDSTs) as preclinical platforms for the assessment of personalized pharmacological therapies. Detailed molecular and phenotypic analyses revealed that MDSTs are the most heterogeneous group of genetically engineered mouse models (GEMMs) of breast cancer yet observed. Response of MDSTs to trametinib, a mitogen-activated protein kinase (MAPK) kinase inhibitor, correlated with RAS/MAPK signaling activity, as expected from studies in xenografts and clinical trials providing validation of the utility of the model. Sensitivity of MDSTs to talazoparib, a poly(adenosine 5'-diphosphate-ribose) polymerase (PARP) inhibitor, was predicted by PARP1 protein levels and by a new PARP sensitivity predictor (PSP) score developed from integrated analysis of drug sensitivity data of human cell lines. PSP score-based classification of The Cancer Genome Atlas breast cancer suggested that a subset of patients with limited therapeutic options would be expected to benefit from PARP-targeted drugs. These results indicate that MDSTs are useful models for studies of targeted therapies, and propose novel potential biomarkers for identification of breast cancer patients likely to benefit from personalized pharmacological treatments.

Management and Outcomes in Metaplastic Breast Cancer

Metaplastic breast cancer (MBC) constitutes a rare clinical entity with special clinicopathologic, immunohistochemical, and molecular features. Resistance to systemic therapies, whether chemotherapy or hormonal therapy, is among its main characteristics, which in turn explains the poor prognosis and renders its management a challenge. Thus, the scope of the present review is to discuss the current therapeutic strategies for MBC in clinical practice and the corresponding outcomes and to suggest possible directions for future research. Potential novel targeted therapies could provide a hope for better outcomes but limited data are available owing to the rarity of MBC. As knowledge accumulates on the pathogenesis and genetic characteristics of MBC, emphasis should be given to the implementation of more targeted treatments, which will allow more efficient and individualized management of the disease.