Adenoid cystic carcinomas constitute a genomically distinct subgroup of triple-negative and basal-like breast cancers

Adenoid Cystic Carcinoma of the Breast and Adjuvant Radiation Therapy: A Review of Literature

OBJECTIVES

Adenoid cystic carcinoma (ACC) of the breast is a rare special histologic type of breast cancer. This tumor is classified as low-grade and has a favorable prognosis, with rare occurrence of metastasis and distinctive characteristics. Due to the uncommon nature of this tumor, there are no specific recommendations regarding the therapeutic management of this malignancy. The aim of this review was to provide an overview of breast ACC clinical characteristics with a special focus on radiotherapy management.

METHODS

A literature review was conducted up to January 2024 through a PubMed search using different combinations of pertinent keywords (eg, Adenoid cystic carcinoma alone, Adenoid cystic carcinoma AND breast Cancer AND radiotherapy; Adenoid cystic carcinoma AND breast cancer AND radiation therapy).

RESULTS

This review highlighted the lack of prospective and randomized data guiding treatment algorithms for ACC. Four retrospective studies explored the impact of postoperative radiation and concluded that postoperative radiation contributes to improved survival.

CONCLUSIONS

Thus, a consideration for radiotherapy indications in ACC of the breast could be further elucidated through prospective randomized studies.

Salivary gland-like tumors of the breast: Histopathologic and genetic features with clinical implications

Salivary gland-like tumors of the breast are rare neoplasms that share morphologic, immunophenotypic, and/or genetic features with their salivary gland counterparts, highlighting a shared underlying histopathogenesis in most cases. Salivary gland-like carcinomas included in the World Health Organization classification of breast tumors are adenoid cystic carcinoma, secretory carcinoma, mucoepidermoid carcinoma, acinic cell carcinoma, and the exceedingly rare polymorphous adenocarcinoma. These carcinomas are usually triple negative for estrogen receptor and progesterone receptor expression and HER2 overexpression, yet generally have favorable prognosis, in contrast to high-grade triple negative carcinomas of no special type. On the other hand, a small subset, such as solid-basaloid adenoid cystic carcinoma, rare high-grade carcinomas, and those associated with transformation to other types of high-grade invasive carcinoma can behave more aggressively. Other salivary gland-like tumors of the breast, such as pleomorphic adenoma and adenomyoepithelioma, are usually benign but can rarely undergo malignant transformation. Although clinical experience with salivary gland-like breast tumors is overall limited, their recognition and accurate classification has important implications for prognosis and clinical management, especially to avoid overtreatment of salivary gland-like carcinomas. The identification of characteristic genetic alterations and/or immunohistochemical surrogates in many of these tumors has practical applications to establishing an accurate diagnosis and directing clinical management. This review highlights the histopathologic and genetic characteristics of salivary gland-like breast tumors and the implications of the diagnosis for current clinical management.

MYB expression by immunohistochemistry is highly specific and sensitive for detection of solid variant of adenoid cystic carcinoma of the breast among all triple-negative breast cancers

BACKGROUND

Adenoid cystic carcinoma is a rare subtype of triple-negative breast carcinoma. These low-grade tumours, which are treated by simple mastectomy and have an excellent prognosis compared to other triple-negative breast carcinomas. Solid-variant adenoid cystic carcinomas have basaloid features and are difficult to distinguish morphologically from other triple-negative breast cancers. Breast adenoid cystic carcinoma exhibits MYB protein overexpression, which can be detected by immunohistochemistry (IHC).

AIM

We compared the IHC expression of MYB in solid-variant adenoid cystic carcinoma with that in other triple-negative breast cancers.

METHODS

We conducted IHC staining of 210 samples of triple-negative breast cancers, including solid-variant adenoid cystic carcinoma (n = 17), metaplastic breast carcinoma (n = 44), basaloid triple-negative breast cancer (n = 21), and other triple-negative invasive ductal carcinoma (n = 128). We classified nuclear staining of MYB as diffuse/strong (3+), focal moderate (2+), focal weak (1+), or none (0).

RESULTS

All 17 solid/basaloid adenoid cystic carcinoma cases exhibited 3+ MYB expression. Of the 21 solid/basaloid triple-negative breast cancers, one (5%) had 2+ expression, seven (33%) 1+ expression, and 13 (62%) 0 expression. Of the 44 metaplastic carcinoma cases, 39 cases (89%) had no (0) staining, and the other five cases had focal weak (1+) or moderate (2+) staining. Among the 128 triple-negative invasive ductal carcinoma cases, 92 cases (72%) had no (0) staining, 36 cases (28%) exhibited focal weak (1+) or moderate (2+) staining.

CONCLUSIONS

Our study revealed diffuse/strong MYB staining (3+) only in solid/basaloid adenoid cystic carcinomas. Thus, we recommend routine MYB IHC staining in triple-negative breast carcinoma with solid/basaloid morphology to improve diagnostic accuracy.

Adenoid cystic carcinoma of the Bartholin's gland is underpinned by MYB- and MYBL1- rearrangements

OBJECTIVE

Adenoid cystic carcinoma (AdCC) of the Bartholin's gland (AdCC-BG) is a very rare gynecologic vulvar malignancy. AdCC-BGs are slow-growing but locally aggressive and are associated with high recurrence rates. Here we sought to characterize the molecular underpinning of AdCC-BGs.

METHODS

AdCC-BGs (n = 6) were subjected to a combination of RNA-sequencing, targeted DNA-sequencing, reverse-transcription PCR, fluorescence in situ hybridization (FISH) and MYB immunohistochemistry (IHC). Clinicopathologic variables, somatic mutations, copy number alterations and chimeric transcripts were assessed.

RESULTS

All six AdCC-BGs were biphasic, composed of ductal and myoepithelial cells. Akin to salivary gland and breast AdCCs, three AdCC-BGs had the MYB::NFIB fusion gene with varying breakpoints, all of which were associated with MYB overexpression by IHC. Two AdCC-BGs were underpinned by MYBL1 fusion genes with different gene partners, including MYBL1::RAD51B and MYBL1::EWSR1 gene fusions, and showed MYB protein expression. Although the final AdCC-BG studied had MYB protein overexpression, no gene fusion was identified. AdCC-BGs harbored few additional somatic genetic alterations, and only few mutations in cancer-related genes were identified, including GNAQ, GNAS, KDM6A, AKT1 and BCL2, none of which were recurrent. Two AdCC-BGs, both with a MYB::NFIB fusion gene, developed metastatic disease.

CONCLUSIONS

AdCC-BGs constitute a convergent phenotype, whereby activation of MYB or MYBL1 can be driven by the MYB::NFIB fusion gene or MYBL1 rearrangements. Our observations further support the notion that AdCCs, irrespective of organ site, constitute a genotypic-phenotypic correlation. Assessment of MYB or MYBL1 rearrangements may be used as an ancillary marker for the diagnosis of AdCC-BGs.

Solid basal adenoid cystic carcinoma of the breast: A case report and literature review

RATIONALE

Adenoid cystic carcinoma (AdCC) is a rare malignancy of the breast with a low Ki-67 index and good prognosis. Owing to the rarity of breast AdCC, the misdiagnosis rate is as high as 50%, and there is no consensus or recognized guidelines for the treatment of this disease. Therefore, it is necessary to conduct a detailed clinical and pathological analysis in combination with a literature review to improve our understanding, diagnosis, and treatment of the disease.

METHODS

A 68-year-old woman sought medical attention due to a recently increasing mass in the breast. The left breast mass was 1.3 cm × 1 cm in size. We analyzed the morphology, immunohistochemistry, and molecular characteristics of the tumor removed by surgery, and reviewed relevant literature.

DIAGNOSES

Solid basal AdCC of the breast.

INTERVENTIONS

We performed biopsy, immunohistochemistry and molecular testing on surgical resection specimens.

OUTCOMES

Combining morphological and immunohistochemical features, it is consistent with solid basal AdCC of the breast, and Fish detected MYB gene break.

LESSONS

Due to the high misdiagnosis rate of AdCC, accurate histopathological diagnosis is particularly important. At present, breast conserving surgery and local tumor resection are mainly used for the treatment of breast AdCC, and postoperative adjuvant radiotherapy is feasible.

The Role of Novel Immunohistochemical Markers for Special Types of Breast Carcinoma

Some histologic special types of breast carcinoma harbor specific recurrent genetic alterations that are not seen in other types of breast carcinoma (no special type), namely adenoid cystic carcinoma, secretory carcinoma, and tall cell carcinoma with reversed polarity. These tumors have unique morphologic features, are triple-negative, that is, do not express hormone receptors or HER2, and are generally associated with a favorable prognosis. Adenoid cystic carcinoma, like its counterpart in other organs, shows a MYB-NFIB fusion gene that is the result of a recurrent t(6;9)(q22-23;p23-24) translocation. Other MYB alterations have been described that result in overexpression of MYB . Secretory carcinoma is characterized by an ETV6-NTRK3 gene fusion that is the result of recurrent (12;15);(p13;q25) translocation, which is also seen in mammary analog secretory carcinoma of the salivary gland. Tall cell carcinoma with reversed polarity shows IDH2 p.Arg172 hotspot mutations. Immunohistochemical antibodies have emerged that identify the underlying genetic alterations in these tumors and serve as useful diagnostic tools. This review will provide an update on the molecular features and diagnostic immunohistochemical markers that have become increasingly popular to aid in diagnosing these uncommon triple-negative breast tumors.

Salivary Gland-like Tumors of the Breast

CONTEXT

The World Health Organization classification of tumors of the breast recognizes several special type carcinomas and benign lesions with features comparable to those of salivary gland tumors.

OBJECTIVE

To discuss the histologic, immunophenotypic, molecular, and clinical features of salivary gland-like carcinomas of the breast. These breast tumors are often negative for hormone receptors and human epidermal growth factor receptor 2 (HER2), that is, triple-negative, but they generally have a much better prognosis than triple-negative breast carcinomas of no special type. We compare the immunophenotypic, molecular, and clinical features of these breast tumors with their salivary gland counterparts, highlighting similarities and differences. We also discuss benign salivary gland-like breast tumors. Finally, we highlight recent developments in understanding the molecular pathogenesis of these breast tumors and novel ancillary studies that can be used to support their diagnosis.

DATA SOURCES

A literature review was conducted, and papers were selected for further analysis and discussion by the authors of this review based on their novelty, applicability, and impact in the field.

CONCLUSIONS

Breast tumors that exhibit morphologic overlap with salivary gland tumors have been recognized by pathologists for decades, but the similarities and differences in their molecular pathogenesis have not been understood until more recently. These developments have led to novel diagnostic tools and further knowledge of these rare breast lesions.

Arbeitsgemeinschaft Gynäkologische Onkologie Recommendations for the Diagnosis and Treatment of Patients with Early Breast Cancer: Update 2023

Background

Each year the interdisciplinary Arbeitsgemeinschaft Gynäkologische Onkologie (AGO), German Gynecological Oncology Group Breast Committee on Diagnosis and Treatment of Breast Cancer provides updated state-of-the-art recommendations for early and metastatic breast cancer.

Summary

The updated evidence-based treatment recommendation for early and metastatic breast cancer has been released in March 2023.

Key Messages

This paper concisely captures the updated recommendations for early breast cancer chapter by chapter.

Unusual presentation of breast adenoid cystic carcinoma resembling adenomyoepithelioma with multiple distinct foci

We describe an unusual case of multifocal breast adenoid cystic carcinoma (AdCC) with adenomyoepitheliomatous morphology. Most breast AdCCs are unifocal and only four cases of multifocal AdCC have been reported previously, however, to our best knowledge, multifocality in AdCC confirmed by molecular analysis has not been reported, so this report adds to the literature on this unique presentation. An 80-year-old woman presented with a left breast mass at 1 o'clock and non-mass enhancement lesion at 5 o'clock on imaging. Incisional biopsy at 1 o'clock showed AdCC based on histopathological features and MYB rearrangement by fluorescent in situ hybridization (FISH). As AdCC involved the margins and the non-mass enhancing lesion remained, mastectomy was performed. Microscopically, the lesion at 5 o'clock demonstrated multinodularity and a biphasic epithelial-basaloid/myoepithelial pattern. Although histological features resembled adenomyoepithelioma, MYB rearrangement was identified on FISH, so the 5 o'clock lesion was also diagnosed as AdCC showing an adenomyoepitheliomatous pattern. This unusual presentation is a potential diagnostic pitfall, so pathologists should consider AdCC as a possible differential diagnosis of multifocal basaloid breast tumors with adenomyoepitheliomatous features.

[Triple-negative breast cancer : Classification, current concepts, and therapy-related factors]

Triple-negative breast cancer (TNBC) accounts for about 10% of all breast cancer cases and is defined by the lack of expression of estrogen and progesterone receptors and the lack of overexpression or amplification of HER2. It differs with regard to the younger age of the patients, an increased association with a mutation of BRCA1 and a mostly low differentiation from hormone receptor-positive breast cancer. The spectrum of triple-negative breast cancer shows considerable heterogeneity both at the morphological and at the molecular level. It includes most commonly TNBC of no special type, with and without basal phenotype, triple-negative metaplastic breast carcinomas, triple-negative breast carcinomas with apocrine differentiation and rare triple-negative tumor types. At the gene-expression level, TNBC most commonly is associated with a basal phenotype, with rarer molecular variants of TNBC involving the Claudin-low, molecular apocrine types, and other rarer subtypes. Therefore, a critical use of the term TNBC, considering the histopathological tumor differentiation, is recommended.

Prognosis stratification and postoperative radiation therapy utilization in adenoid cystic carcinoma of the breast

PURPOSE

Adenoid cystic carcinoma of the breast (ACCB) is a rare malignancy with a favorable prognosis. Little information exists regarding the impact of postoperative radiation therapy (RT) on survival outcome in patients with ACCB. This study aimed to evaluate the clinical significance of postoperative RT in ACCB.

METHODS

Data of patients with ACCB were extracted from the Surveillance, Epidemiology, and End Results database (2000-2019). Univariate and multivariable Cox regression analyses were performed to identify prognostic factors. In addition, a nomogram model was constructed and internally validated for discrimination and calibration. The value of postoperative RT was respectively accessed in each risk subgroup according to nomogram-deduced individualized score.

RESULTS

A total of 689 eligible patients were included in the analysis. Partial mastectomy was associated with an increased risk of death compared with partial mastectomy plus postoperative RT (P = 0.020), but total mastectomy with or without postoperative RT was comparable (P = 0.624). Then, in-depth analysis was performed for patients receiving breast-conserving therapy (n = 485, the training set vs. the testing set = 340 vs. 145). Age at diagnosis, histological grade, and T stage were identified as prognostic factors for overall survival (OS) (All P < 0.05). A nomogram was constructed to provide predictive accuracy toward individual OS rates of ACCB and to divide patients into different risk subgroups. Notably, compared with non-RT, postoperative RT significantly improved OS in the high-risk subgroup (P = 0.006 for the training set, and P = 0.013 for the overall population) but not in the low-risk subgroup (P = 0.807 for the training set, and P = 0.293 for the overall population), suggesting that these patients may be able to exempt from postoperative RT.

CONCLUSION

A robust and effective nomogram was developed to predict prognosis and assist in treatment decisions in patients with ACCB undergoing partial mastectomy.

Comparative proteomic and clinicopathological analysis of breast adenoid cystic carcinoma and basal-like triple-negative breast cancer

Background

Adenoid cystic carcinoma (ACC) is a rare type of triple-negative breast cancer that has an indolent clinical behavior. Given the substantial overlapping morphological, immunohistochemical, and molecular features with other basal-like triple-negative breast cancer (BL-TNBC), accurate diagnosis of ACC is crucial for effective clinical treatment. The integrative analysis of the proteome and clinicopathological characteristics may help to distinguish these two neoplasms and provide a deep understanding on biological behaviors and potential target therapy of ACC.

Methods

We applied mass spectrometry-based quantitative proteomics to analyze the protein expression in paired tumor and adjacent normal breast tissue of five ACC and five BL-TNBC. Bioinformatic analyses and the clinicopathological characteristics, including histological features, immunohistochemistry, and FISH results, were also collected to get comprehensive information.

Results

A total of 307 differentially expressed proteins (DEPs) were identified between ACC and BL-TNBC. Clustering analysis of DEPs clearly separated ACC from BL-TNBC. GSEA found downregulation of the immune response of ACC compared with BL-TNBC, which is consistent with the negative PD-L1 expression of ACC. Vesicle-mediated transport was also inhibited, while ECM organization was enriched in ACC. The top upregulated proteins in DEPs were ITGB4, VCAN, and DPT. Moreover, in comparison with normal breast tissue, ACC showed elevated ribosome biogenesis and RNA splicing activity.

Conclusion

This study provides evidence that ACC presents a substantially different proteomic profile compared with BL-TNBC and promotes our understanding on the molecular mechanisms and biological processes of ACC, which might be useful for differential diagnosis and anticancer strategy.

MYB RNA In Situ Hybridization Is a Useful Diagnostic Tool to Distinguish Breast Adenoid Cystic Carcinoma From Other Triple-negative Breast Carcinomas

Breast adenoid cystic carcinoma (AdCC) has overlapping features with basal-like triple-negative breast carcinoma (TNBC), yet carries a more favorable prognosis, and accurate diagnosis is critical. Like salivary gland AdCC, breast AdCC demonstrates recurrent alterations in the MYB gene. Novel chromogenic RNA in situ hybridization (ISH) for MYB has emerged as sensitive and specific for salivary gland AdCC. Here, we evaluate MYB RNA ISH in invasive ductal carcinomas (IDCs) including basal-like TNBC, and in the histologic mimics ductal carcinoma in situ (DCIS) and collagenous spherulosis. MYB RNA ISH was also performed on previously constructed tissue microarrays containing 78 evaluable IDC, including 30 basal-like TNBC (EGFR+ and/or CK5/6+), 19 luminal A (ER+/HER-2-), 12 HER-2+ (ER-/HER-2+), 11 non-basal-like TNBC, and 6 luminal B (ER+/HER-2+). MYB RNA ISH overexpression was seen in 100% (n=18/18) of primary breast AdCC and 10% (n=8/78) of IDC (P<0.0001). MYB RNA ISH was overexpressed in 37% (n=7/19) of luminal A and 8% (n=1/12) of HER-2+ IDC, and in no cases of TNBC or luminal B IDC. The majority (67%, n=8/12) of DCIS and all (n=7) cases of collagenous spherulosis demonstrated overexpression of MYB RNA. MYB gene rearrangement was detected in 67% (n=4/6) evaluable AdCC. Although MYB RNA ISH overexpression cannot be used to distinguish between cribriform DCIS or collagenous spherulosis and AdCC, MYB RNA ISH is absent in basal-like TNBC and rare in ER+ or HER-2+ IDC. MYB RNA ISH could be a useful, sensitive, and rapid diagnostic adjunct in the workup of a triple-negative carcinoma in the breast.

Distinct clinicopathological and genomic features in solid and basaloid adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma (AdCC) of the breast is a rare indolent carcinoma of salivary gland-type tumors, frequently associated with MYB genetic alteration. Solid and basaloid adenoid cystic carcinoma (SB-AdCC) is considered a sparse variant of AdCC. This study sought to search for clinicopathological and genomic features in SB-AdCC. Registered clinicopathological data on a cohort of 13 AdCC of the breast cases, including six conventional adenoid cystic carcinoma (C-AdCC) cases and seven SB-AdCC cases, were collected. MYB gene rearrangement via fluorescent in situ hybridization was investigated and MYB protein expression was evaluated by immunohistochemistry. Compared with C-AdCC, we found that the distribution of SB-AdCC cases were shifted to older age and were more frequently distant metastasis. Moreover, metastasis cases also showed a high (exceed 30%) Ki-67 index. Both groups showed MYB rearrangements and MYB protein expression, but they were less frequent in SB-AdCC than C-AdCC. To conclude, our results suggest that SB-AdCC is an aggressive variant of mammary AdCC with a higher incidence of distant metastases compared with C-AdCC, though they share common molecular features. A high Ki-67 index may be an adverse prognostic factor for metastasis.

Breast adenoid cystic carcinoma: a report of seven cases and literature review

Background

Primary adenoid cystic carcinoma (ACC) of breast is rarely seen clinically. It is a special subtype of triple-negative breast cancer characterized by low expression of Ki-67, low malignant potential, slow progression and favorable prognosis. To date, treatment for this disease is controversial and no consensus is reached. We analyzed clinical manifestations and pathological characteristics of seven primary breast ACC cases and reported in combination with literature review to promote understanding, diagnosis and treatment of this disease.

Case presentation

We collected seven breast ACC cases pathologically diagnosed and treated in Department of breast surgery of the First Affiliated Hospital of China Medical University from January 2015 to December 2018. We organized and summarized the clinical, imaging, pathological and prognostic information and performed statistical analysis. The median age was 60 years (ranging from 54 to 64 years). Tumors of all patients were detected by immunohistochemistry. Molecular types were mostly triple negative (4/7), and Ki-67 expression was low (5/7). Lymph node metastases were absent in all patients received axillary lymph node surgery. Median follow-up time was 39 months (ranging from 25 to 68 months). There was no occurrence of relapse, distant metastasis or death.

Conclusion

Breast ACC is accompanied with favorable diagnosis, which is different from typical triple-negative breast cancer. Accurate diagnosis of ACC is particularly important.

Special Histologic Type and Rare Breast Tumors - Diagnostic Review and Clinico-Pathological Implications

Breast cancer is the most common malignant tumor in females. While most carcinomas are categorized as invasive carcinoma, no special type (NST), a diverse group of tumors with distinct pathologic and clinical features is also recognized, ranging in incidence from relatively more common to rare. So-called "special histologic type" tumors display more than 90% of a specific, distinctive histologic pattern, while a spectrum of tumors more often encountered in the salivary gland may also arise in the breast. Metaplastic carcinomas can present diagnostic challenges. Some uncommon tumors harbor pathognomonic genetic alterations. This article provides an overview of the key diagnostic points and differential diagnoses for this group of disparate lesions, as well as the salient clinical characteristics of each entity.

The clinical behavior and genomic features of the so-called adenoid cystic carcinomas of the solid variant with basaloid features

Classic adenoid cystic carcinomas (C-AdCCs) of the breast are rare, relatively indolent forms of triple negative cancers, characterized by recurrent MYB or MYBL1 genetic alterations. Solid and basaloid adenoid cystic carcinoma (SB-AdCC) is considered a rare variant of AdCC yet to be fully characterized. Here, we sought to determine the clinical behavior and repertoire of genetic alterations of SB-AdCCs. Clinicopathologic data were collected on a cohort of 104 breast AdCCs (75 C-AdCCs and 29 SB-AdCCs). MYB expression was assessed by immunohistochemistry and MYB-NFIB and MYBL1 gene rearrangements were investigated by fluorescent in-situ hybridization. AdCCs lacking MYB/MYBL1 rearrangements were subjected to RNA-sequencing. Targeted sequencing data were available for 9 cases. The invasive disease-free survival (IDFS) and overall survival (OS) were assessed in C-AdCC and SB-AdCC. SB-AdCCs have higher histologic grade, and more frequent nodal and distant metastases than C-AdCCs. MYB/MYBL1 rearrangements were significantly less frequent in SB-AdCC than C-AdCC (3/14, 21% vs 17/20, 85% P < 0.05), despite the frequent MYB expression (9/14, 64%). In SB-AdCCs lacking MYB rearrangements, CREBBP, KMT2C, and NOTCH1 alterations were observed in 2 of 4 cases. SB-AdCCs displayed a shorter IDFS than C-AdCCs (46.5 vs 151.8 months, respectively, P < 0.001), independent of stage. In summary, SB-AdCCs are a molecularly heterogeneous but clinically aggressive group of tumors. Less than 25% of SB-AdCCs display the genomic features of C-AdCC. Defining whether these tumors represent a single entity or a collection of different cancer types with a similar basaloid histologic appearance is warranted.

Pathogenesis of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) encompasses a heterogeneous group of fundamentally different diseases with different histologic, genomic, and immunologic profiles, which are aggregated under this term because of their lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. Massively parallel sequencing and other omics technologies have demonstrated the level of heterogeneity in TNBCs and shed light into the pathogenesis of this therapeutically challenging entity in breast cancer. In this review, we discuss the histologic and molecular classifications of TNBC, the genomic alterations these different tumor types harbor, and the potential impact of these alterations on the pathogenesis of these tumors. We also explore the role of the tumor microenvironment in the biology of TNBCs and its potential impact on therapeutic response. Dissecting the biology and understanding the therapeutic dependencies of each TNBC subtype will be essential to delivering on the promise of precision medicine for patients with triple-negative disease.

Molecular analysis of TCGA breast cancer histologic types

Breast cancer is classified into multiple distinct histologic types, and many of the rarer types have limited characterization. Here, we extend The Cancer Genome Atlas Breast Cancer (TCGA-BRCA) dataset with additional histologic type annotations, in a total of 1063 breast cancers. We analyze this extended dataset to define transcriptomic and genomic profiles of six rare special histologic types: cribriform, micropapillary, mucinous, papillary, metaplastic, and invasive carcinoma with medullary pattern. We show the broader applicability of our constructed special histologic type gene signatures in the TCGA Pan-Cancer Atlas dataset with a predictive model that detects mucinous histologic type across cancers of other organ systems. Using a normal mammary cell differentiation score analysis, we order histologic types into a continuum from stem cell-like to luminal progenitor-like to mature luminal-like. Finally, we classify TCGA-BRCA into 12 consensus groups based on integrated genomic and histological features. We present a rich openly accessible resource of histologic and genomic characterization of TCGA-BRCA to enable studies of the range of breast cancers.

TH1902, a new docetaxel-peptide conjugate for the treatment of sortilin-positive triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subgroup of cancers which lacks the expression and/or amplification of targetable biomarkers (ie, estrogen receptor, progestrogen receptor, and human epidermal growth factor receptor 2), and is often associated with the worse disease-specific outcomes than other breast cancer subtypes. Here, we report that high expression of the sortilin (SORT1) receptor correlates with the decreased survival in TNBC patients, and more importantly in those bearing lymph node metastases. By exploiting SORT1 function in ligand internalization, a new anticancer treatment strategy was designed to target SORT1-positive TNBC-derived cells both in vitro and in two in vivo tumor xenografts models. A peptide (TH19P01), which requires SORT1 for internalization and to which many anticancer drugs could be conjugated, was developed. In vitro, while the TH19P01 peptide itself did not exert any antiproliferative or apoptotic effects, the docetaxel-TH19P01 conjugate (TH1902) exerted potent antiproliferative and antimigratory activities when tested on TNBC-derived MDA-MB-231 cells. TH1902 triggered faster and more potent apoptotic cell death than did unconjugated docetaxel. The apoptotic and antimigratory effects of TH1902 were both reversed by two SORT1 ligands, neurotensin and progranulin, and on siRNA-mediated silencing of SORT1. TH1902 also altered microtubule polymerization and triggered the downregulation of the anti-apoptotic Bcl-xL biomarker. In vivo, both i.p. and i.v. administrations of TH1902 led to greater tumor regression in two MDA-MB-231 and HCC-70 murine xenograft models than did docetaxel, without inducing neutropenia. Altogether, the data demonstrates the high in vivo efficacy and safety of TH1902 against TNBC through a SORT1 receptor-mediated mechanism. This property allows for selective treatment of SORT1-positive TNBC and makes TH1902 a promising avenue for personalized therapy with the potential of improving the therapeutic window of cytotoxic anticancer drugs such as docetaxel.

Adenoid cystic carcinoma and basaloid carcinoma of the breast: A clinicopathological study

Adenoid cystic carcinoma of the breast (ACCB) is a rare triple negative tumor (TNT) with an excellent prognosis in most cases. Three different histologic types are recognized: classic ACCB, solid basaloid ACCB (SB-ACCB), and ACCB with high-grade transformation. A majority of these tumors show characteristic molecular and immunohistochemical (IHC) features, with fusion of MYB and NFIB genes and overexpression of MYB, respectively. Basaloid carcinomas of the breast (BCB) are infrequently described. They resemble SB-ACCB and TNT of no special type (TNT-NST). We have studied the clinicopathological features of 17 ACCB and 9 BCB, investigating the expression of MYB by IHC and the rearrangements of MYB by fluorescence in situ hybridization (FISH). MYB was expressed by IHC in 15 ACCB and in 3 BCB. MYB FISH detected rearrangements in 11 ACCB and in 2 BCB. After a mean follow-up of 90 months, with a range of 12-204 months, 2 patients with ACCB with high-grade transformation and 1 patient with BCB developed metastases and died of disease. In summary, most ACCB have a good prognosis, but tumors with adverse histopathological features may metastasize. BCB may overlap with ACCB and TNT-NST, and their prognosis should be further studied.

Breast Cancer-Epidemiology, Risk Factors, Classification, Prognostic Markers, and Current Treatment Strategies-An Updated Review

Breast cancer (BC) is the most frequently diagnosed cancer in women worldwide with more than 2 million new cases in 2020. Its incidence and death rates have increased over the last three decades due to the change in risk factor profiles, better cancer registration, and cancer detection. The number of risk factors of BC is significant and includes both the modifiable factors and non-modifiable factors. Currently, about 80% of patients with BC are individuals aged >50. Survival depends on both stage and molecular subtype. Invasive BCs comprise wide spectrum tumors that show a variation concerning their clinical presentation, behavior, and morphology. Based on mRNA gene expression levels, BC can be divided into molecular subtypes (Luminal A, Luminal B, HER2-enriched, and basal-like). The molecular subtypes provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. The eighth edition of TNM classification outlines a new staging system for BC that, in addition to anatomical features, acknowledges biological factors. Treatment of breast cancer is complex and involves a combination of different modalities including surgery, radiotherapy, chemotherapy, hormonal therapy, or biological therapies delivered in diverse sequences.

Benefit of adjuvant chemotherapy in patients with special histology subtypes of triple-negative breast cancer: a systematic review

PURPOSE

Breast cancer (BC) is a leading cause of morbidity, disability, and mortality in women, worldwide; triple-negative BC (TNBC) is a subtype traditionally associated with poorer prognosis. TNBC special histology subtypes present distinct clinical and molecular features and sensitivity to antineoplastic treatments. However, no consensus has been defined on the best adjuvant therapy. The aim of the review is to study the evidence from literature to inform the choice of adjuvant treatments in this setting.

METHODS

We systematically searched literature assessing the benefit of adjuvant chemotherapy in patients with TNBC special histotypes (PROSPERO: CRD42020153818).

RESULTS

We screened 6404 records (15 included). All the studies estimated the benefit of different chemotherapy regimens, in retrospective cohorts (median size: 69 patients (range min-max: 17-5142); median follow-up: 51 months (range: 21-268); mostly in Europe and USA). In patients with early-stage adenoid cystic TNBC, a marginal role of chemotherapy was reported. Similar for apocrine TNBC. Medullary tumors exhibited an intrinsic good prognosis with a limited role of chemotherapy, suggested to be modulated by the presence of tumor-infiltrating lymphocytes. A significant impact of chemotherapy on the overall survival was estimated in patients with metaplastic TNBC. Limitations were related to the retrospective design of all the studies and heterogeneous treatments received by the patients.

CONCLUSIONS

There is potential opportunity to consider treatment de-escalation and less intense therapies in some patients with early, special histology-type TNBC. International efforts are indispensable to validate prospective clinical decision models.

A Review Leveraging a Rare and Unusual Case of Basal Cell Carcinoma of the Prostate

Basal cell carcinoma (BCC) is a rare nonacinar variant of prostatic carcinoma. In spite of prostatic acinar adenocarcinoma being one of the most common carcinomas in prostate, <100 prostatic BCC cases have been reported to date. Adenoid cystic/cribriform histology has been described in varying proportions to occur in prostatic BCC and is reported to be associated with aggressive behavior and high risk of metastasis. Herein, we present a case of prostatic BCC with adenoid cystic morphology, comprehensively describe its immunohistochemical and MYB/MYBL1 gene rearrangement findings, discuss its differential diagnosis, and review the literature of this rare entity.

A Case of Solid Variant of Adenoid Cystic Carcinoma from Trachea: A Case Report and Review of Literature

Introduction

Primary tracheal adenoid cystic carcinoma (ACC) is a rare and heterogeneous group of neoplasms arising from the respiratory tract. The solid variant of ACC is a histologically distinct subtype with an unfavorable clinical course. We report on a case of tracheal ACC with immunohistochemical and molecular analysis together with a review of the literature.

Case Report

We observed a case in which a 31-year-old male presented with a neoplasm bulging into the lumen and caused symptoms of tracheal obstruction and even hemoptysis. Cytological smears of an endobronchial fine needle aspiration revealed aggregates of basaloid cells with small to medium size, scant cytoplasm, and evenly hyperchromatic nuclei. Histologically, the tumor is characterized by a predominant compact sheet-like and nested pattern of rounded basaloid cells. Immunohistochemically, the tumor was diffusely positive for CK and CD117. CK7 and CK5/6 were focally positive in the genuine glandular structures. P63 was completely negative in the majority of neoplastic cells. Fluorescence in situ hybridization analysis revealed MYB gene rearrangement.

Conclusion

The solid variant of ACC from trachea is rare and hence poses diagnostic difficulty. Computed tomography (CT) scan and bronchoscopy help assess the extent of the disease. Histological features combined with immunophenotypic and molecular analysis aid in distinguishing this uncommon type from other round cell neoplasms. The accurate diagnosis can help expedite treatment of this highly aggressive tumor.

Problematic breast tumors reassessed in light of novel molecular data

Breast cancer is a vastly heterogeneous disease encompassing a panoply of special histological subtypes. Although rare breast tumors have largely not been investigated systematically in large scale genomics series, recent studies have shed light on the genetic underpinnings of special histologic subtypes of breast cancer. Genomic analyses of estrogen receptor-positive special histologic types of breast cancer have not resulted in the identification of novel pathognomonic genetic alterations in addition to the confirmation of the presence of CDH1 loss-of-function mutations in invasive lobular carcinomas. By contrast, the analyses of triple-negative breast cancers have demonstrated that low-grade triple-negative breast cancers categorically differ from the common forms of high-grade triple-negative disease biologically and phenotypically and are underpinned by specific fusion genes or hotspot mutations. A subset of low-grade triple-negative disease has been shown to harbor highly recurrent if not pathognomonic genetic alterations, such as ETV6-NTRK3 fusion gene in secretory carcinomas, the MYB-NFIB fusion gene, MYBL1 rearrangements or MYB gene amplification in adenoid cystic carcinomas, and HRAS Q61 hotspot mutations coupled with mutations in PI3K pathway genes in estrogen receptor-negative adenomyoepitheliomas. A subset of these pathognomonic genetic alterations (e.g., NTRK1/2/3 fusion genes) now constitute an FDA approved indication for the use of TRK inhibitors in the advanced/metastatic setting. These studies have also corroborated that salivary gland-like tumors of the breast, other than acinic cell carcinomas, harbor the repertoire of somatic genetic alterations detected in their salivary gland counterparts. Reassuringly, the systematic study of special histologic types of breast cancer utilizing state-of-the-art sequencing approaches, rather than rendering pathology obsolete, has actually strengthened the importance of breast cancer histologic typing and is providing additional ancillary markers for the diagnosis of these rare but fascinating entities.

Diagnosis of metastatic adenoid cystic carcinoma of the breast on pleural fluid cytology in a 60-year-old male

Adenoid cystic carcinoma (AdCC) is a rare triple-negative breast cancer with a favorable prognosis, although cases of distant metastases have been reported. Less than 10 cases of AdCC of the breast in males have been reported. We report a unique presentation of pleural fluid metastasis diagnosed by cytologic evaluation of pleural fluid in a 60-year-old male patient with AdCC of the breast. Careful surveillance and cytologic evaluation of effusion specimens can detect metastases with the aid of cellblock preparations and immunohistochemical stains.

Treatment Patterns and Clinical Outcomes of Adenoid Cystic Breast Carcinoma: A Single-Institution Experience

BACKGROUND

Adenoid cystic breast carcinoma (ACC) is a rare subtype of triple-negative breast cancer. We aim to characterize the treatment patterns and clinical outcomes of women diagnosed with ACC at a large medical center.

METHODS

Female patients diagnosed with ACC at our institution between 2009 and 2019 were retrospectively identified. Patients with limited clinicopathologic data were excluded.

RESULTS

In our final study cohort (n = 9), the majority of ACCs (6/9, 66.7%) were hormone receptor (-) (HR-) and HER-2/neu (-) (HER2-), while 3 ACCs were HR+ HER2-. Two patients received adjuvant chemotherapy, and 4 patients received adjuvant radiotherapy. The crude local and distant recurrence rate of our cohort was 22.2% and 11.1% (median follow-up of 36 months).

CONCLUSIONS

The majority of ACCs were triple negative but some ACCs were HR+. The unadjusted local and distant recurrence rates were not negligible, suggesting that adjuvant chemotherapy and radiotherapy may be warranted in select cases.

Activation of PLAG1 and HMGA2 by gene fusions involving the transcriptional regulator gene NFIB

The pleomorphic adenoma (PA), which is the most common salivary gland neoplasm, is a benign tumor characterized by recurrent chromosome rearrangements involving 8q12 and 12q14-15. We have previously shown that the PLAG1 and HMGA2 oncogenes are the targets of these rearrangements. Here, we have identified previously unrecognized subsets of PAs with ins(9;8)/t(8;9) (n = 5) and ins(9;12)/t(9;12) (n = 8) and breakpoints located in the vicinity of the PLAG1 and HMGA2 loci. RNA-sequencing and reverse transcriptase (RT)-PCR analyses of a case with an ins(9;8) revealed a novel NFIB-PLAG1 fusion in which NFIB exon 4 is linked to PLAG1 exon 3. In contrast to the developmentally regulated PLAG1 gene, NFIB was highly expressed in normal salivary gland, indicating that PLAG1 in this case, as in other variant fusions, is activated by promoter swapping. RT-PCR analysis of three PAs with t(9;12) revealed two tumors with chimeric transcripts consisting of HMGA2 exon 4 linked to NFIB exons 9 or 3 and one case with a fusion linking HMGA2 exon 3 to NFIB exon 9. The NFIB fusion events resulted in potent activation of PLAG1 and HMGA2. Analysis of the chromatin landscape surrounding NFIB revealed several super-enhancers in the 5'- and 3'-parts of the NFIB locus and its flanking sequences. These findings indicate that PLAG1 and HMGA2, similar to MYB in adenoid cystic carcinoma, may be activated by enhancer-hijacking events, in which super-enhancers in NFIB are translocated upstream of PLAG1 or downstream of HMGA2. Our results further emphasize the role of NFIB as a fusion partner to multiple oncogenes in histopathologically different types of salivary gland tumors.

Solid-type adenoid cystic carcinoma of the breast, a distinct molecular entity enriched in NOTCH and CREBBP mutations

Adenoid cystic carcinoma (ACC) of the breast with a predominant solid pattern is difficult to diagnose with certainty and differentiate from more common triple-negative breast cancers (TNBCs) of basal-phenotype. To better characterize solid ACC, we performed a clinical, morphological, immunohistochemical, and molecular comparative analysis of 33 ACCs of the breast comprising 17 solid variant ACCs and 16 conventional ACCs. Solid ACCs displayed basaloid morphology with an exclusive or predominant epithelial cell population associated with decreased myoepithelial differentiation, while demonstrating MYB protein overexpression similar to the more common type of ACC. Strong and diffuse MYB expression by immunochemistry was observed in 14/17 (82%) of solid ACCs while MYB rearrangements were detected by break apart fluorescence in situ hybridization (FISH) in only 3/16 (19%) of solid ACCs. Conversely, weak MYB immunohistochemical expression was observed in only 7/204 (3%) of TNBC. Solid ACCs displayed a transcriptomic profile distinct from conventional ACCs with 549 genes showing a highly significant differential expression between conventional and solid ACC [false discovery rate (FDR) < 0.01; log2FC > |1|]. EnrichR and Kegg Pathway analyses identified PI3K-Akt and focal adhesion signaling pathways as significantly overexpressed in conventional ACCs compared with solid ACCs which significantly overexpressed the nitrogen metabolism pathway. CREBBP mutations and NOTCH activating gene mutations were only present in solid ACCs, concerning 5/16 (31%) of cases for each gene. Tumors with NOTCH activating mutations displayed a strong diffuse nuclear NICD1 staining, an established marker of Notch pathway activation. Solid ACCs also differed from basal-type TNBC, with fewer TP53 mutations and a more stable genomic profile on array comparative genomic hybridization (CGH). In summary, solid-type ACC of the breast is a distinct molecular entity within the ACC family and is different from common basal-type TNBC. MYB is a diagnostically useful biomarker of solid ACC and NOTCH could be a novel potential therapeutic target in 30% of cases.

A review of mucinous lesions of the breast

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocele-like lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The finding of free-floating or stromal mucin accumulations is a diagnostic challenge of which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between benign and malignant mucin-producing lesions, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with associated with mucinous, myxoid, or matrix material.

Predictors of Outcome in Mammary Adenoid Cystic Carcinoma: A Multi-Institutional Study

Mammary adenoid cystic carcinoma (ACC) is a rare subtype of breast cancer with a favorable prognosis. Here we report on predictors of outcome based on a detailed morphologic review and analysis of 108 mammary ACC. Sixty-four tumors (59.2%) were pure conventional ACC, 23 (21.3%) were pure basaloid ACC. Follow-up was available for 87 patients (median: 51 mo). Eighteen patients (20.7%) developed recurrence: 7 (8%) had local recurrence and 14 (16%) had distant metastasis. Two patients died of disease, 1 died of an unrelated cause, 14 were alive with disease (including 8 in palliative care), and 70 (80.5%) were alive with no evidence of disease. Of 90 patients with known lymph node (LN) status 9 (10%) had nodal involvement (all with basaloid ACC). Distant metastases in patients with predominantly basaloid ACC compared with pure conventional ACC were more common (40% vs. 7.7%) and occurred earlier (22 vs. 84 mo). The following factors were found to be predictive of recurrence-free survival: positive margin, Nottingham grade, neovascularization, basaloid component, perineural invasion, lymphovascular invasion, >30% solid growth, necrosis and LN involvement; the first 3 remained statistically significant on multivariate analysis. Factors predictive of distant disease-free survival were neovascularization, Nottingham grade, lymphovascular invasion, solid component >50%, LN involvement, basaloid component >50%, tumor necrosis, perineural invasion, and final margin. Only neovascularization remained statistically significant on multivariate analysis. Basaloid ACC is an aggressive variant of mammary ACC with more frequent nodal involvement and higher incidence of distant spread. LN staging should be performed for all mammary basaloid ACC.

Detecting MYB and MYBL1 fusion genes in tracheobronchial adenoid cystic carcinoma by targeted RNA-sequencing

Primary tracheobronchial adenoid cystic carcinoma is rare, accounting for less than 1% of all lung tumors. Many adenoid cystic carcinomas have been reported to have a specific chromosome translocation t(6;9)/MYB-NFIB. More recently, t(8;9)/MYBL1-NFIB gene fusion was reported in salivary gland adenoid cystic carcinomas which lacked a t(6;9)/MYB-NFIB. Two prior studies showed t(6;9)/MYB-NFIB in tracheobronchial adenoid cystic carcinoma; however, only rare cases of MYBL1 rearrangement have been reported in this carcinoma. In this study, we used targeted RNA sequencing to investigate fusion genes in tracheobronchial adenoid cystic carcinoma at our institution. Fusions of either MYB or MYBL1 genes were detected in 7 of 7 carcinomas. Three cases had MYB-NFIB, and 3 had MYBL1-NFIB. The remaining case showed a rare MYBL1-RAD51B fusion. These findings suggest that rearrangement involving MYB or MYBL1 is a hallmark of tracheobronchial adenoid cystic carcinoma.

SOX10 Is a Sensitive Marker for Breast and Salivary Gland Adenoid Cystic Carcinoma: Immunohistochemical Characterization of Adenoid Cystic Carcinomas

Breast adenoid cystic carcinomas (AdCCs) can pose diagnostic difficulty due to their rarity, particularly on limited biopsy material. Given that these tumors are triple-negative breast cancers with favorable prognosis, accurate diagnosis is critical for clinical management. A total of 12 cases of breast AdCCs were studied; 17 age-matched salivary gland AdCCs and 5 metastatic AdCCs (1 breast and 4 salivary gland primaries) were also examined. Immunohistochemical stains for SOX10, Ki-67, c-KIT, β-catenin, epithelial membrane antigen (EMA), p63, cytokeratin 7 (CK7), cytokeratin 5/6 (CK5/6), and androgen receptor (AR) were performed. All breast (100%) and metastatic (100%) AdCCs and all but 2 salivary gland AdCCs showed diffuse nuclear staining (>50% of cells) for SOX10. Epithelial membrane antigen showed lowest expression in breast AdCCs and the highest expression in metastatic AdCCs (P < .01). Except one case of salivary gland AdCC that showed loss of β-catenin expression and developed subsequent metastasis, all AdCCs showed strong and diffuse membranous β-catenin expression. There were no significant differences in expression of CK7, p63, CK5/6, AR, Ki-67, and c-KIT (P > .05) among breast, salivary gland, and metastatic AdCCs. We investigated the immunophenotypic features of breast AdCCs in comparison with salivary gland and metastatic AdCCs. Despite the contrast in prognosis, these tumors are immunophenotypically similar. SOX10 is a sensitive diagnostic marker in all AdCCs, which could potentially aid in diagnosis of these tumors on limited material.

Breast Carcinoma: Updates in Molecular Profiling 2018

The most significant contribution of molecular subtyping of breast carcinomas has been the identification of estrogen-positive and estrogen-negative tumor subtypes. Knowledge of genetic alterations in these tumors will help clinicians identify novel therapeutic targets. Understanding the progression pathways involved in the transition of in situ carcinoma to invasive carcinoma might lead to efficient risk stratification in these patients. The Cancer Genome Analysis Network has collected genomic and epigenomic data to provide comprehensive information regarding carcinogenesis and pathway interactions. Such information improves understanding of the disease process and also provides more accurate information toward identifying targetable mutations for treatment.

Synchronous Ovarian and Breast Cancers with a Novel Variant in BRCA2 Gene: A Case Report

We report a case of a 52-year-old female with a family history of pancreatic and colon cancers who presented with a right breast mass positive for high-grade medullar carcinoma with triple-negative biomolecular profile. Further workup was performed finding a left ovarian mass. The patient underwent laparotomy performing optimal cytoreduction on bilateral ovarian tumors; the pathology and immunohistochemistry confirmed bilateral ovary adenocarcinoma with positive peritoneal malignancy. Due to her synchronic breast and ovarian cancers, a genetic profile was performed detecting a new pathogenic variant in the BRCA2 gene: c.3606_3607del (p.Ser1203Cysfs). She was given chemotherapy with carboplatin and paclitaxel obtaining complete clinical response. Regarding her breast cancer, she had a right modified radical mastectomy and prophylactic left mastectomy obtaining complete clinical response. This case presents with an unusual subtype and difficult histologic diagnosis of a synchronic medullar breast cancer and ovary carcinoma associated with a new mutation of the BRCA2 gene.

Assessment of HMGA2 and PLAG1 rearrangements in breast adenomyoepitheliomas

Breast adenomyoepitheliomas (AMEs) are rare epithelial-myoepithelial neoplasms that may occasionally produce myxochondroid matrix, akin to pleomorphic adenomas (PAs). Regardless of their anatomic location, PAs often harbor rearrangements involving HMGA2 or PLAG1. We have recently shown that the repertoire of somatic genetic alterations of AMEs varies according to their estrogen receptor (ER) status; whilst the majority of ER-positive AMEs display mutually exclusive PIK3CA or AKT1 hotspot mutations, up to 60% of ER-negative AMEs harbor concurrent HRAS Q61 hotspot mutations and mutations affecting either PIK3CA or PIK3R1. Here, we hypothesized that a subset of AMEs lacking these somatic genetic alterations could be underpinned by oncogenic fusion genes, in particular those involving HMGA2 or PLAG1. Therefore, we subjected 13 AMEs to RNA-sequencing for fusion discovery (n = 5) and/or fluorescence in situ hybridization (FISH) analysis for HMGA2 and PLAG1 rearrangements (n = 13). RNA-sequencing revealed an HMGA2-WIF1 fusion gene in an ER-positive AME lacking HRAS, PIK3CA and AKT1 somatic mutations. This fusion gene, which has been previously described in salivary gland PAs, results in a chimeric transcript composed of exons 1-5 of HMGA2 and exons 3-10 of WIF1. No additional in-frame fusion genes or HMGA2 or PLAG1 rearrangements were identified in the remaining AMEs analyzed. Our results demonstrate that a subset of AMEs lacking mutations affecting HRAS and PI3K pathway-related genes may harbor HMGA2-WIF1 fusion genes, suggesting that a subset of breast AMEs may be genetically related to PAs or that a subset of AMEs may originate in the context of a PA.

Cancers du sein triple-négatifs : données actuelles et perspectives d’avenir

Le cancer du sein triple-négatif (CSTN), défini par l’absence d’expression des récepteurs hormonaux et d’HER2 (human epidermal growth factor receptor-2), représente 15 à 20 % des cancers du sein. Cependant, cette définition, essentiellement négative, masque la très grande hétérogénéité des entités biologiques qui constituent ce soustype. Si la chimiothérapie est le principal traitement systémique établi de la maladie à la fois dans la prise en charge des stades précoces et avancés, la compréhension progressive des composantes moléculaires impliquées dans la pathogenèse des CSTN permet des perspectives thérapeutiques novatrices. L’objectif de cette synthèse est de décrire ces cibles potentielles et d’explorer les traitements d’aujourd’hui et de demain qui permettront de lutter contre ce cancer au comportement particulièrement agressif.

Adenoid cystic carcinoma of the vagina: A case report

RATIONALE

Squamous carcinoma is the most common malignancy of vagina. Adenoid cystic carcinoma (ACC) in the vagina is very rare.

PATIENT CONCERNS

In the present study, we present a 45-year-old woman with a palpable swelling in the vagina. The patient reported body paresthesia, chest congestion, expiratory dyspnea, and itching in the thigh root.

DIAGNOSIS

The ultrasound results revealed inhomogeneous echoes of the muscular layer in the middle and distal of the vagina, and probed a slightly richer blood flow signal. Then biopsy was performed. On microscopic examination, it was observed that tumor cells were arranged in a tubular or cribriform pattern, and exhibited a consistent size, small nuclei, and nuclear fission. The myoepithelium was lined around the glandular cavity, but the myoepithelium was tumorous. Immunohistochemistry was performed for further verification. Vimentin was positive in mesenchyme and CK-P was positive in epithelial cells. P63 and calponin were spotted, which were focal positive around the glandular cavity. Finally, the patient was diagnosed as ACC.

INTERVENTIONS

At last, the patient chose chemoradiotherapy, not surgical excision.

OUTCOMES

The patient is alive and well 13 months after the initial diagnosis.

LESSONS

ACC in the vagina is extremely rare. To our knowledge, this report is the first case of ACC arising from the vagina in English-language literature. Extensive surgical section of the tumour and chemoradiotherapy are recommended for therapy. Because of rarity, the prognosis of ACC in vagina is not known.

Adenoid cystic carcinoma of the breast: Experience at a tertiary care centre of Northern India

INTRODUCTION

Adenoid cystic carcinoma of the breast (breast-ACC) is a rare tumor with a favorable prognosis, despite its triple-negative status and special type of basal-like tumor for which scant population-based descriptive data exist. We sought to provide new population-based information on breast-ACC in India. Due to the paucity of the number of cases, the natural history of the disease is not fully understood. This study was undertaken to examine the clinico-pathological characteristics of the disease and to evaluate the outcome of surgical intervention in a tertiary referral care centre.

MATERIALS AND METHODS

A retrospective analysis of all patients diagnosed and treated for ACC Breast in our hospital over the past 10 years was carried out (2005-2015). A database of the characteristics of these patients was developed. In all, 14 patients were identified. The investigations performed included routine blood investigations, chest X-ray, bone scan and either an ultrasound or a CT scan.

RESULTS

During the time period of 10 years, of 2347 with breast malignancy admitted to our department, only 14 were diagnosed as having ACC (3.15%). All patients were women (100%). The patients had a median age of 60.7 years (range 37-81). The most common symptom was lump in the breast. Two patients (14.2%) presented with nipple and skin retraction and two patients (14.2%) were asymptomatic with the diagnosis made by an incidental finding on routine examination. The CT and/or magnetic resonance imaging (MRI) showed the typical features of carcinoma breast. All the 14 patients were taken up for surgery. Nine patients underwent Modified radical mastectomy and five patients underwent Breast conservation surgery. Axillary lymph node dissection was carried out in seven patients and sentinel lymph node biopsy in the remaining. Tumor cells had a characteristic histologic pattern of ACC of the breast. Perineural invasion was present in six cases.

DISCUSSION

ACC of the breast is a very rare malignancy, accounting for less than 0.1% of all breast neoplasms. It affects the left and right breasts equally and tumors arise irrespective of the breast quadrants. However, in about 50 percent of patients, lesions are found in subareolar region. Pain or tenderness described in the minority of cases has not been correlated with histologically-confirmed perineural invasion. ACC is categorized as a basal-like subtype of breast carcinoma. Most cases are macroscopically well-circumscribed. Occasionally, pink, tan, or gray microcysts are evident. A tumor typically consists of a dual-cell population of luminal and myoepithelial-basal cells which may be arranged in one or more of three architectural patterns: tubular-trabecular, cribriform, and solid-basaloid. There is no consensus on the optimal management for patients with ACC of the breast. Based on its indolent clinical course and favorable outcome, ACC of the breast is generally cured by breast-conserving surgery, such as wide excision or quadrantectomy with or without radiotherapy.

CONCLUSION

Breast-ACC among women is characterized by ER-negative/PR-negative expression, rare regional lymph node involvement, a favorable prognosis with excellent survival, and absence of associated cancers. These findings reinforce the importance of tailored treatments for breast-ACC and the apparent heterogeneity of basal-like breast cancers.

Adenoid cystic carcinomas of the salivary gland, lacrimal gland, and breast are morphologically and genetically similar but have distinct microRNA expression profiles

Adenoid cystic carcinoma is among the most frequent malignancies in the salivary and lacrimal glands and has a grave prognosis characterized by frequent local recurrences, distant metastases, and tumor-related mortality. Conversely, adenoid cystic carcinoma of the breast is a rare type of triple-negative (estrogen and progesterone receptor, HER2) and basal-like carcinoma, which in contrast to other triple-negative and basal-like breast carcinomas has a very favorable prognosis. Irrespective of site, adenoid cystic carcinoma is characterized by gene fusions involving MYB, MYBL1, and NFIB, and the reason for the different clinical outcomes is unknown. In order to identify the molecular mechanisms underlying the discrepancy in clinical outcome, we characterized the phenotypic profiles, pattern of gene rearrangements, and global microRNA expression profiles of 64 salivary gland, 9 lacrimal gland, and 11 breast adenoid cystic carcinomas. All breast and lacrimal gland adenoid cystic carcinomas had triple-negative and basal-like phenotypes, while salivary gland tumors were indeterminate in 13% of cases. Aberrations in MYB and/or NFIB were found in the majority of cases in all three locations, whereas MYBL1 involvement was restricted to tumors in the salivary gland. Global microRNA expression profiling separated salivary and lacrimal gland adenoid cystic carcinoma from their respective normal glands but could not distinguish normal breast adenoid cystic carcinoma from normal breast tissue. Hierarchical clustering separated adenoid cystic carcinomas of salivary gland origin from those of the breast and placed lacrimal gland carcinomas in between these. Functional annotation of the microRNAs differentially expressed between salivary gland and breast adenoid cystic carcinoma showed these as regulating genes involved in metabolism, signal transduction, and genes involved in other cancers. In conclusion, microRNA dysregulation is the first class of molecules separating adenoid cystic carcinoma according to the site of origin. This highlights a novel venue for exploring the biology of adenoid cystic carcinoma.

Histologic heterogeneity of triple negative breast cancer: A National Cancer Centre Database analysis

BACKGROUND

Triple negative breast cancer (TNBC) is an aggressive disease, but recent studies have identified heterogeneity in patient outcomes. However, the utility of histologic subtyping in TNBC has not yet been well-characterised. This study utilises data from the National Cancer Center Database (NCDB) to complete the largest series to date investigating the prognostic importance of histology within TNBC.

METHODS

A total of 729,920 patients (pts) with invasive ductal carcinoma (IDC), metaplastic breast carcinoma (MBC), medullary breast carcinoma (MedBC), adenoid cystic carcinoma (ACC), invasive lobular carcinoma (ILC) or apocrine breast carcinoma (ABC) treated between 2004 and 2012 were identified in the NCDB. Of these, 89,222 pts with TNBC that received surgery were analysed. Kaplan-Meier analysis, log-rank testing and multivariate Cox proportional hazards regression were utilised with overall survival (OS) as the primary outcome.

RESULTS

MBC (74.1%), MedBC (60.6%), ACC (75.7%), ABC (50.1%) and ILC (1.8%) had significantly different proportions of triple negativity when compared to IDC (14.0%, p < 0.001). TNBC predicted an inferior OS in IDC (p < 0.001) and ILC (p < 0.001). Lumpectomy and radiation (RT) were more common in MedBC (51.7%) and ACC (51.5%) and less common in MBC (33.1%) and ILC (25.4%), when compared to IDC (42.5%, p < 0.001). TNBC patients with MBC (HR 1.39, p < 0.001), MedBC (HR 0.42, p < 0.001) and ACC (HR 0.32, p = 0.003) differed significantly in OS when compared to IDC.

CONCLUSION(S)

Our results indicate that histologic heterogeneity in TNBC significantly informs patient outcomes and thus, has the potential to aid in the development of optimum personalised treatments.

MYB and MYBL1 in adenoid cystic carcinoma: diversity in the mode of genomic rearrangement and transcripts

MYB-NFIB and MYBL1-NFIB have been reported in ~60% of adenoid cystic carcinoma cases, but driver alterations in the remaining ~40% of adenoid cystic carcinoma remain unclear. We examined 100 adenoid cystic carcinoma cases for MYB and MYBL1 locus rearrangements by fluorescence in situ hybridization (FISH) with originally designed probe sets using formalin-fixed paraffin-embedded materials. Approximately one-third of samples were also analyzed by fusion transcript-specific RT-PCR and capture RNA sequencing. In the 27 cases with frozen materials, MYB-NFIB and MYBL1-NFIB fusion transcripts were detected in 9 (33%) and 6 cases (22%) by RT-PCR, respectively. Meanwhile, high expression of MYB (18 cases, 67%) or MYBL1 (9 cases, 33%) was detected in all 27 cases in a mutually exclusive manner, regardless of its form (full-length, truncation, or fusion transcript). Interestingly, genomic rearrangements around the corresponding highly-expressed gene were observed in all 27 cases by FISH, suggesting a causative relationship between genomic rearrangements and gene expression. Among the 100 cases, including additional 73 cases, 97 harbored genomic rearrangements in the MYB (73 cases) or MYBL1 locus (24 cases) including 10 cases with atypical FISH patterns undetectable through ordinary split FISH approaches: breakpoints far distant from MYB (5 cases) and a small NFIB locus insertion into the MYB (3 cases) or MYBL1 locus (2 cases). In clinicopathological analyses, histological grade, primary tumor size, and lymph node metastasis were identified as prognostic factors, whereas MYB/MYBL1 rearrangements were not, but were associated with histological grade. In the present study, MYB or MYBL1 locus rearrangement was detected in nearly all adenoid cystic carcinoma cases, and therefore it would be a good diagnostic marker for adenoid cystic carcinoma. However, fusion transcript-specific RT-PCR for MYB-NFIB and MYBL1-NFIB and ordinary split FISH assays for MYB and MYBL1 were less sensitive, and thus detection methods should be judiciously designed because of the diversity of rearrangement modes in adenoid cystic carcinoma.

Molecular Classification of Breast Cancer

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