BRCA1 germline mutation in a woman with metaplastic squamous cell breast cancer

Translational Aspects in Metaplastic Breast Carcinoma

Breast cancer is the most common cancer among women. Metaplastic breast carcinoma (MpBC) is a rare, heterogeneous group of invasive breast carcinomas, which are classified as predominantly triple-negative breast carcinomas (TNBCs; HR-negative/HER2-negative). Histologically, MpBC is classified into six subtypes. Two of these are considered low-grade and the others are high-grade. MpBCs seem to be more aggressive, less responsive to neoadjuvant chemotherapy, and have higher rates of chemoresistance than other TNBCs. MpBCs have a lower survival rate than expected for TNBCs. MpBC treatment represents a challenge, leading to a thorough exploration of the tumor immune microenvironment, which has recently opened the possibility of new therapeutic strategies. The epithelial-mesenchymal transition in MpBC is characterized by the loss of intercellular adhesion, downregulation of epithelial markers, underexpression of genes with biological epithelial functions, upregulation of mesenchymal markers, overexpression of genes with biological mesenchymal functions, acquisition of fibroblast-like (spindle) morphology, cytoskeleton reorganization, increased motility, invasiveness, and metastatic capabilities. This article reviews and summarizes the current knowledge and translational aspects of MpBC.

Metaplastic carcinoma of the breast and BRCA1 germline mutation: a case report and review

BACKGROUND

Metaplastic carcinoma of the breast consists of both invasive ductal carcinoma and metaplastic carcinoma. This rare subtype of cancer has a poor prognosis. The development of metaplastic breast cancer and relationship with BRCA1 are not well known. Here, we report a rare case of germline BRCA1 mutation-positive breast cancer with chondroid metaplasia.

CASE PRESENTATION

A 39-year-old Japanese woman with a family history of breast cancer in her mother and ovarian cancer in her maternal grandmother consulted at our hospital with a left breast mass. Needle biopsy for the mass was performed, leading to a diagnosis of invasive breast cancer with chondroid metaplasia. We performed left mastectomy + sentinel lymph node biopsy + tissue expander insertion and replaced with a silicone implant later. Pathological examination revealed that the patient had triple-negative breast cancer. Four courses of doxorubicin+ cyclophosphamide therapy were performed as adjuvant therapy after surgery. We performed genetic counseling and genetic testing, and the results suggested the germline BRCA1 mutation 307 T> A (L63*). She has currently lived without a relapse for 2 years post-surgery.

CONCLUSIONS

There have been only 6 cases of metaplastic breast carcinoma with germline BRCA1 mutations including our case. Patients with BRCA1 mutations may develop basal-like subtypes or M type of triple-negative breast cancer besides metaplastic breast cancers.

Pathology of Hereditary Breast and Ovarian Cancer

Hereditary breast and ovarian cancer (HBOC) syndrome is most commonly characterized by deleterious germline mutations in BRCA1 and BRCA2. HBOC patients are prone to the development of malignant neoplasms in multiple organs including the breast, ovary, and fallopian tube. From a pathological perspective, a number of morphological features have been described in BRCA-associated breast and tubo-ovarian cancers. For example, breast cancers diagnosed in BRCA1-mutation carriers are frequently of a high Nottingham grade and display medullary morphology and a triple-negative and/or a basal-like immunophenotype. In contrast, breast cancers in BRCA2-mutation carriers are similar to sporadic luminal-type tumors that are positive for hormone receptors and lack expression of human epidermal growth factor receptor 2. Cancers arising in the fallopian tube and ovary are almost exclusively of a high-grade serous histotype with frequent Solid, pseudo-Endometrioid, and Transitional cell carcinoma-like morphology (“SET features”), marked nuclear atypia, high mitotic index, abundant tumor infiltrating lymphocytes, and necrosis. In addition, pushing or infiltrative micropapillary patterns of invasion have been described in BRCA-associated metastases of tubo-ovarian high-grade serous carcinomas. Besides BRCA1 and BRCA2 mutations, alterations in a number of other homologous recombination genes with moderate penetrance, including PALB2, RAD51C, RAD51D, BRIP1, and others, have also been described in HBOC patients with varying frequency; however, distinct morphological characteristics of these tumors have not been well characterized to date. In this review, the above pathological features are discussed in detail and a focus is placed on how accurate pathologic interpretation plays an important role in allowing HBOC patients to receive the best possible management.

Molecular Features of Metaplastic Breast Carcinoma: An Infrequent Subtype of Triple Negative Breast Carcinoma

Metaplastic breast carcinoma (MBC) is a heterogeneous group of infrequent invasive carcinomas that display differentiation of the neoplastic epithelium towards squamous cells and/or mesenchymal-type elements. Most MBC have a triple negative phenotype and poor prognosis. Thus, MBC have worse survival rates than other invasive breast carcinomas, including other triple negative breast carcinomas (TNBC). In this study, we reviewed the molecular features of MBC, pointing out the differences among subtypes. The most frequently mutated genes in MBC were TP53 and PIK3CA. Additionally, mutations in the other genes of the PI3K/AKT pathway indicated its importance in the pathogenesis of MBC. Regarding copy number variations (CNVs), MYC was the most frequently amplified gene, and the most frequent gene loss affected the CDKN2A/CDKN2B locus. Furthermore, the pattern of mutations and CNVs of MBC differed from those reported in other TNBC. However, the molecular profile of MBC was not homogeneous among histological subtypes, being the alterations in the PI3K pathway most frequent in spindle cell carcinomas. Transcriptomic studies have demonstrated an epithelial to mesenchymal program activation and the enrichment of stemness genes in most MBC. In addition, current studies are attempting to define the immune microenvironment of these tumors. In conclusion, due to specific molecular features, MBC have a different clinical behavior from other types of TNBC, being more resistant to standard chemotherapy. For this reason, new therapeutic approaches based on tumor molecular characteristics are needed to treat MBC.

Estrogen receptor-positive primary squamous cell carcinoma of the breast

Pure primary squamous cell carcinoma of the breast (SCCB) represents around 0.1% of breast carcinomas. Diagnosis requires independence from adjacent skin without metastatic disease. SCCB is often large at presentation with nonspecific mammographic and ultrasound findings. It is typically hormone receptor negative and aggressive. Mastectomy and adjuvant chemotherapy is the most common treatment, although treatment guidelines are not well established. We present a case of pure primary SCCB detected by high risk screening mammogram and treated with breast conserving surgery, chemotherapy, and radiation. We discuss clinical, radiologic, and pathologic findings.

First description of an acinic cell carcinoma of the breast in a BRCA1 mutation carrier: a case report

Background

Acinic cell carcinoma (ACC) is a rare malignant epithelial neoplasm characterized by the presence of malignant tubular acinar exocrine gland structures. Diagnosis is generally made in salivary glands and in the pancreas. ACC of the breast has been reported in few cases only. Carriers of inherited mutations in the BRCA1 gene are prone to the development of breast cancer, mainly invasive ductal or medullary type carcinomas. We describe for the first time a BRCA1 mutation carrier with a diagnosis of ACC of the breast.

Case presentation

The patient developed an invasive ductal carcinoma (IDC) at the age of 40 years and an ACC in the contralateral breast at 44 years. Immunohistochemical examination of the ACC revealed a triple negative status (i.e., negativity for estrogen receptor, progesterone receptor and HER2 protein) and positivity for p53. Using a combination of loss of heterozygosity (LOH) and sequencing analyses, the loss of the wild-type BRCA1 allele was detected in both the ACC and the IDC. In addition, two different somatic TP53 mutations, one in the ACC only and another one in the IDC only, were observed.

Conclusion

Both the immunohistochemical and molecular features observed in the ACC are typical of BRCA1-associated breast cancers and suggest an involvement of the patient’s germline mutation in the disease. The occurrence of rare histological types of breast cancers, including malignant phyllodes tumor, atypical medullary carcinoma and metaplastic carcinoma, in BRCA1 mutation carriers has been already reported. Our findings further broaden the spectrum of BRCA1-associated breast malignancies.

Triple-negative breast cancers: an updated review on treatment options

Morphologic features of tumour cells have long been validated for the clinical classification of breast cancers and are regularly used as a "gold standard" to ascertain prognostic outcome in patients. Identification of molecular markers such as expression of the receptors for estrogen (er) and progesterone (pgr) and the human epidermal growth factor receptor 2 (her2) has played an important role in determining targets for the development of efficacious drugs for treatment and has also offered additional predictive value for the therapeutic assessment of patients with breast cancer. More recent technical advancements in identifying several cancer-related genes have provided further opportunities to identify specific subtypes of breast cancer. Among the subtypes, tumours with triple-negative cells are identified using specific staining procedures for basal markers such as cytokeratin 5 and 6 and the absence of er, pgr, and her2 expression. Patients with triple-negative breast cancers therefore have the disadvantage of not benefiting from currently available receptor-targeted systemic therapy. Optimal conditions for the therapeutic assessment of women with triple-negative breast tumours and for the management of their disease have yet to be validated in prospective investigations. The present review discusses the differences between triple-negative breast tumours and basal-like breast tumours and also the role of mutations in the BRCA genes. Attention is also paid to treatment options available to patients with triple-negative breast tumours.

A deleterious BRCA1 mutation in a young Pakistani woman with metaplastic breast carcinoma

Metaplastic breast carcinoma (MBC) is a relatively rare subtype of breast cancer that encompasses a pathologically heterogeneous group of tumors. Pathogenic germ line mutations in the major breast cancer susceptibility genes BRCA1 and BRCA2 genes have been rarely found or described in MBC. We report the identification of the BRCA1 185delAG mutation in a 22-year-old Pakistani woman with triple-negative MBC that showed biphasic morphological features, including sarcomatous and malignant epithelial components. A comprehensive description of the clinical, histopathological, morphological, and immunohistochemical features of the tumor and the patient's treatment course is presented.

Primary squamous cell carcinoma of breast with ipsilateral axillary lymph node metastasis: An unusual case

INTRODUCTION

Pure squamous cell carcinoma of the breast [SCCB] is rare.

PRESENTATION OF CASE

We report a case of primary squamous cell carcinoma of breast with ipsilateral axillary lymph node metastasis in a 58year old woman.

DISCUSSION

It is a breast carcinoma entirely composed of metaplastic squamous cells that may be keratinized, non-keratinized or spindled. The pure squamous cell carcinoma usually present with central cystic cavity, which we found in our case, also supported by immunohistochemical evidence.

CONCLUSION

Although a rare breast cancer subtype, SCCB is of considerable interest due to its pathological heterogeneity and differences in clinical behavior and less reported occurrence of nodal metastasis.

Low-grade adenosquamous carcinoma of the breast--A case report with a BRCA1 germline mutation

Breast cancers occurring in women with germline BRCA1 mutations tend to fall into the category of triple-negative or basal-like phenotypes, such as metaplastic carcinoma. Low-grade adenosquamous carcinoma of the breast is a rare variant of metaplastic carcinoma. We present the case of a 49-year-old woman with a past medical history of invasive ductal breast carcinoma 13 years ago, and who was recently diagnosed as having a low-grade adenosquamous carcinoma in the same breast. Genetic analysis of blood DNA revealed a BRCA1 mutation. To our knowledge, BRCA1 mutation in association with a low-grade adenosquamous carcinoma of the breast has not yet been reported. Thus, it may be important to consider the possibility of an association, but supplemental studies are needed.