HER2-low metastases of HER2-negative primary tumors: a single institution analysis of intertumoral and internodal heterogeneity in node-positive breast cancer.

Objective: HER2 status in breast cancer is an essential parameter in individual therapeutic decision-making and is routinely assessed in primary tumors in accordance with international recommendations. Reports of HER2 heterogeneity raise the question of basing treatment decisions on HER2 status in metastases, if present. We investigated the degree and clinical implications of HER2 heterogeneity in lymph node-positive breast cancer. Because of recent recognition of therapeutic opportunities in this group of tumors, we especially focused on cases involving low-level HER2 expression. Methods: The HER2 status of primary tumors and of corresponding lymph node metastases was determined in archived material at the protein and gene levels using the gene- protein assay and interpreted in accordance with 2018 ASCO/CAP criteria. HER2-low status was defined as protein expression levels 1+ or 2+ with negative amplification status. Results: We analyzed a series of 43 cases of primary infiltrating breast cancer, each with at least two axillary nodes harboring macrometastases (>2 mm), in total 206 such nodes. In 7% of cases, we detected intertumoral HER2 heterogeneity. Three of nine HER2-positive primary tumors were associated with HER2-negative metastases. No cases with HER2-negative primary tumors had HER2-positive metastases, but 55% (6/11) of HER2 0 primary tumors had HER2 1+ and/or 2+ metastases, and 19% (3/16) HER2 1+ cases had exclusively HER2 0 metastases. All metastases in HER2 2+ cases showed HER2-low protein expression levels. Internodal HER2 heterogeneity at low protein expression levels (presence of HER2 0, HER2 1+, and/or HER2 2+ metastatic deposits within the same axilla) was seen in 40% (17/43) of cases. We found no statistically significant association between HER2 heterogeneity and other tumor-related parameters. Survival data indicated worse outcomes in the HER2-low group compared with the rest of the cohort. Conclusion: Our results indicate a substantial instability of HER2 protein expression, leading to considerable intertumoral and internodal HER2 heterogeneity in lymph node-positive breast carcinomas. This heterogeneity is particularly relevant in HER2-low tumors in which the corrective effects of HER2 gene copy number analysis definitionally is absent. Our findings suggest that determining HER2 status in metastatic lymph nodes may generate relevant information for therapeutic decision-making.

Triple-Negative Breast Cancer Histological Subtypes with a Favourable Prognosis.

Triple-negative breast cancers (TNBC), as a group of tumours, have a worse prognosis than stage-matched non-TNBC and lack the benefits of routinely available targeted therapy. However, TNBC is a heterogeneous group of neoplasms, which includes some special type carcinomas with a relatively indolent course. This review on behalf of the European Working Group for Breast Screening Pathology reviews the literature on the special histological types of BC that are reported to have a triple negative phenotype and indolent behaviour. These include adenoid cystic carcinoma of classical type, low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, low-grade mucoepidermoid carcinoma, secretory carcinoma, acinic cell carcinoma, and tall cell carcinoma with reversed polarity. The pathological and known molecular features as well as clinical data including treatment and prognosis of these special TNBC subtypes are summarised and it is concluded that many patients with these rare TNBC pure subtypes are unlikely to benefit from systemic chemotherapy. A consensus statement of the working group relating to the multidisciplinary approach and treatment of these rare tumour types concludes the review.

Integrative meta-analysis of gene expression profiles identifies FEN1 and ENDOU as potential diagnostic biomarkers for cervical squamous cell carcinoma.

Cervical carcinoma is a global public health burden. Given that it is usually asymptomatic at potentially curative stages, the development of clinically accurate tests is critical for early detection and individual risk stratification. The present study performed an integrative meta-analysis of the transcriptomes from 10 cervical carcinoma cohorts, with the aim of identifying biomarkers that are associated with malignant transformation of cervical epithelium, and establish their clinical applicability. From among the top ranked differentially expressed genes, flap structure-specific endonuclease 1 (FEN1) and poly (U)-specific endoribonuclease (ENDOU) were selected for further validation, and their clinical applicability was assessed using immunohistochemically stained microarrays comprising 110 tissue cores, using p16 and Ki67 staining as the comparator tests. The results demonstrated that FEN1 expression was significantly upregulated in 65% of tumor specimens (P=0.0001), with no detectable expression in the non-tumor tissues. Furthermore, its expression was significantly associated with Ki67 staining in tumor samples (P<0.0001), but no association was observed with p16 expression or the presence of human papilloma virus types 16/18, patient age, tumor grade or stage. FEN1 staining demonstrated lower sensitivity than p16 (69.3 vs. 96.8%) and Ki67 (69.3 vs. 76.3%); however, the specificity was identical to p16 and higher than that of Ki67 (100 vs. 71.4%).ENDOU staining was consistent with the microarray results, demonstrating 1% positivity in tumors and 40% positivity in non-tumor tissues. Gene set enrichment analysis of cervical tumors overexpressing FEN1 revealed its association with enhanced growth factor signaling, immune response inhibition and extracellular matrix remodeling, whereas tumors with low ENDOU expression exhibited inhibition of epithelial development and differentiation processes. Taken together, the results of the present study demonstrate the feasibility of the integrative meta-analysis approach to identify relevant biomarkers associated with cervical carcinogenesis. Thus, FEN1 and ENDOU may be useful diagnostic biomarkers for squamous cervical carcinoma. However, further studies are required to determine their diagnostic performance in larger patient cohorts and validate the results presented here.

Granulomatous mastitis caused by Rickettsia species.

Granulomatous mastitis is a rare inflammatory disease of varying etiology. Tuberculosis and cystic neutrophilic granulomatous mastitis caused by Corynebacterium are the best-established infectious examples. Despite the increasing incidence of Rickettsia-related diseases worldwide, granulomatous inflammation of breast parenchyma caused by Rickettsia has not yet been reported. We present a unique case of bilateral granulomatous mastitis documented with mammography, magnetic resonance imaging and core-needle biopsy. The rickettsial etiology of the disease was proved with specific immunohistochemistry and confirmed with DNA extraction, PCR and serology. The lesions completely resolved after a full-course tetracycline treatment. This case report widens the knowledge about the possible clinical manifestations of Rickettsia infection and adds a new bacterium to the list of etiological factors causing granulomatous mastitis.

The clinical value of detecting microcalcifications on a mammogram.

Many breast lesions are associated with microcalcifications that are detectable by mammography. In most cases, radiologists are able to distinguish calcifications usually associated with benign diseases from those associated with malignancy. In addition to their value in the early detection of breast carcinoma and accurate radiological diagnosis, the presence of microcalcifications often affects the extent of surgical intervention. Certain types of microcalcifications are associated with negative genetic and molecular characteristics of the tumor and unfavorable prognosis. Microcalcifications localized in the larger ducts (duct-centric, casting-type microcalcifications) represent an independent negative prognostic marker compared to lesions containing other types of microcalcifications and to non-calcified lesions. In this review, we summarize the theoretical and methodological background for understanding the clinical impact and discuss the diagnostic and prognostic value of microcalcifications detected in the breast by mammography.

The subgross morphology of breast carcinomas: a single-institution series of 2033 consecutive cases documented in large-format histology slides.

A large-format histology technique represents the most convenient method for documenting and assessing the subgross morphological prognostic parameters of breast cancer (i.e., the distribution of the tumor's invasive and in situ components, disease extent, and tumor size), especially when used in conjunction with systematic radiological-pathological correlation. Here we report a consecutive series of 2033 breast carcinomas operated on in Dalarna, Sweden, with a particular focus on these subgross parameters. We separately analyzed the distributions of the in situ and invasive components of the tumors and then combined these into an aggregate pattern when both components were present. We found that 40% of breast carcinomas had a simple (unifocal) subgross morphology, while 60% had a complex morphology presenting with multifocal or diffuse components. Extensive tumors (occupying a total volume of breast tissue with the greatest dimension being ≥ 40 mm) were more common in complex cases, occurring in 66% of multifocal cases and 88% of diffuse cases, compared with only 5% of unifocal cases. Compared with luminal A-like tumors, HER2-expressing tumors exhibited a significantly larger extent. Triple-negative and basal-like carcinomas tended to have a larger tumor size (based on the largest dimension of the largest invasive focus). In this report, we discuss the prognostic impact of these parameters and the necessity of their correct assessment in the diagnostic routine.

Imaging Biomarkers as Predictors for Breast Cancer Death.

BACKGROUND: To differentiate the risk of breast cancer death in a longitudinal cohort using imaging biomarkers of tumor extent and biology, specifically, the mammographic appearance, basal phenotype, histologic tumor distribution, and conventional tumor attributes. METHODS: Using a prospective cohort study design, 498 invasive breast cancer patients diagnosed between 1996 and 1998 were used as the test cohort to assess the independent effects of the imaging biomarkers and other predictors on the risk of breast cancer death. External validation was performed with a cohort of 848 patients diagnosed between 2006 and 2010. RESULTS: Mammographic tumor appearance was an independent predictor of risk of breast cancer death (P=0.0003) when conventional tumor attributes and treatment modalities were controlled. The casting type calcifications and architectural distortion were associated with 3.13-fold and 3.19-fold risks of breast cancer death, respectively. The basal phenotype independently conferred a 2.68-fold risk compared with nonbasal phenotype. The observed deaths did not differ significantly from expected deaths in the validation cohort. The application of imaging biomarkers together with other predictors classified twelve categories of risk for breast cancer death. CONCLUSION: Combining imaging biomarkers such as the mammographic appearance of the tumor with the histopathologic distribution and basal phenotype, accurately predicted long-term risk of breast cancer death. The information may be relevant for determining the need for molecular testing, planning treatment, and determining the most appropriate clinical surveillance schedule for breast cancer patients.

Internodal HER2 heterogeneity of axillary lymph node metastases in breast cancer patients.

Determination of human epidermal growth factor receptor 2 (HER2) status is important for adequate treatment of breast cancer (BC) patients. The novel HER2 gene protein assay (GPA) is particularly convenient, as it allows the simultaneous assessment of HER2 protein expression and gene amplification at individual cell level. Here we investigated the frequency of internodal HER2 heterogeneity in axillary lymph node macrometastases of BC patients and compared HER2 status between primary breast tumor and its metastases. We included a total of 41 female patients operated between 2014 and 2015 for primary BC with axillary lymph node macrometastases. Representative paraffin blocks of metastatic lymph nodes were sectioned and the slides were stained using the GPA in 38 BC cases. GPA results were assessed according to the ASCO/CAP 2013 criteria. We analyzed 12586 individual tumor cells, 120 cells per section of each metastatic lymph node. HER2 status differed between the primary tumor and its metastases in 5/38 cases (13.2%). In patients with at least two metastatic nodes, the HER2 status of lymph node metastases was only slightly different in 4/23 cases (17.4%). Our results indicate rare but substantial differences in HER2 status between primary breast tumor and its axillary lymph node metastases that may direct the choice and outcomes of targeted therapy in BC patients. The impact of the rare and subtle internodal HER2 heterogeneity evidenced in this study remains uncertain. Determining the HER2 status of lymph node metastases in BC seems to be rational, but assessing a limited number of metastatic nodes may be sufficient.

Equivocal (HER2 IHC 2+) breast carcinomas: gene-protein assay testing reveals association between genetic heterogeneity, individual cell amplification status and potential treatment benefits.

AIMS: Genetic heterogeneity can pose a challenge to identifying eligible cases for targeted therapy in the human epidermal growth factor receptor 2 (HER2) immunohistochemistry (IHC) 2+ breast carcinoma group. In this study, we characterised this subset of tumours according to clinicopathological parameters. METHODS AND RESULTS: We assessed 1000 tumour cells per case and recorded the number of HER2 and chromosome enumeration probe 17 (CEP17) copies using gene-protein assay slides. HER2 status was determined based on ASCO/CAP 2013 guidelines. Tumours with 5-50% of cancer cells with amplification were considered to be heterogeneous, whereas those with >50% were considered to be non-heterogeneous. In a study cohort of 110 HER2 IHC 2+ carcinomas, 93 (84.5%) were non-amplified, 12 (10.9%) were amplified and five (4.5%) were ISH-equivocal. All the HER2-amplified and two of ISH-equivocal cases (12.7%) corresponded to non-heterogeneous tumours, with highly significant differences evident in the average HER2/CEP17 ratio (P = 0.0002) and the proportion of cells with HER2 >6 copies (P < 0.0001) compared with heterogeneous lesions. NST grade 3 and HER2-amplified carcinomas average HER2/CEP17 ratio correlated with an increased number of cells with HER2/CEP17 ≥2.0 (P < 0.014). Triple-negative CEP17 polysomic carcinomas showed increased metastatic capacity (P = 0.003) compared with other tumour types. CONCLUSION: Non-heterogeneous HER2 IHC 2+ tumours tend to be HER2-amplified. Adding the percentage of cells with HER2 >6 copies to the average HER2/CEP17 ratio may facilitate assessment of amplification status in ISH-equivocal cases. The proportion of cells with HER2/CEP17 ≥2.0 contributes information concerning the actual average HER2/CEP17 ratio, depending on tumour type.

Eccrine ductal and acrosyringeal metaplasia in breast carcinomas: report of eight cases.

Eccrine ductal and acrosyringeal metaplasia was described in 2006 as the presence of tumor structures that resemble the epithelium of the eccrine skin ducts and their opening within the epidermis, the acrosyringeum. Here, we report the clinical, morphological, and phenotypic characteristics of eight breast carcinomas that we collected over the past years showing this metaplasia. Unlike squamous metaplasia, acrosyringeal and eccrine ductal metaplasia are luminated structures comprising cells with eosinophilic cytoplasm that are easily detectable in routine histological slides. These lesions invariably appeared in triple-negative carcinomas, but the cases differed in their clinical, radiological, and histological manifestations. Correct interpretation of these changes may facilitate identification of some metaplastic carcinomas.

LRIG1 negatively regulates RET mutants and is downregulated in thyroid cancer.

Papillary thyroid carcinoma (PTC) and medullary thyroid carcinoma (MTC) are characterized by genomic rearrangements and point mutations in the proto-oncogene RET. Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is a suppressor of various receptor tyrosine kinases, including RET. LRIG1 expression levels are associated with patient survival in many cancer types. In the present study, we investigated whether the oncogenic RET mutants RET2A (C634R) and RET2B (M918T) were regulated by LRIG1, and the possible effects of LRIG1 expression in thyroid cancer were investigated in three different clinical cohorts and in a RET2B-driven mouse model of MTC. LRIG1 was shown to physically interact with both RET2A and RET2B and to restrict their ligand-independent activation. LRIG1 mRNA levels were downregulated in PTC and MTC compared to normal thyroid gland tissue. There was no apparent association between LRIG1 RNA or protein expression levels and patient survival in the studied cohorts. The transgenic RET2B mice developed pre-cancerous medullary thyroid lesions at a high frequency (36%); however, no overt cancers were observed. There was no significant difference in the incidence of pre-cancerous lesions between Lrig1 wild-type and Lrig1-deficient RET2B mice. In conclusion, the findings that LRIG1 is a negative regulator of RET2A and RET2B and is also downregulated in PTC and MTC may suggest that LRIG1 functions as a thyroid tumor suppressor.

The new TNM-based staging of breast cancer.

This review describes the changes that have been implemented in the Tumor-Node-Metastasis (TNM)-based staging of breast cancers by the new, 8th editions of the relevant Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) publications. After giving a background for TNM being the common language of cancer staging and related activities like cancer treatment and registration, it summarizes not only the changes but reviews some highlights important for pathologists, and lists and comments on the differences between the publications and diagnostic practices based on them. A section is dedicated to the prognostic stages of breast carcinomas introduced in the AJCC Cancer Staging Manual, but not mentioned in the UICC TNM classification of malignant tumors. A few issues that are not appropriately covered by TNM according to the authors' view (e.g., multifocal tumors, larger lymph node metastases identified by molecular methods, the heterogeneous prognosis of M1-defined stage IV disease) close the review with the final thoughts raising the vision of a potential loss of the common staging language.

The sick lobe hypothesis, field cancerisation and the new era of precision breast surgery.

Understanding the ductal anatomy of the breast provides insights into tumorigenesis, which in turn offers guidance on therapeutic decisions. In this regard, the sick lobe hypothesis, which states that cancer arises from genetically unstable cells through mutations acquired in utero, forms the basis of malignant transformation. These 'at risk' cells line the mammary ductal-lobular system of a single 'sick' lobe and when exposed to noxious events in the surrounding microenvironment, further genetic changes occur which completes conversion to malignancy, in certain defined patterns. This review explores how anatomy, pathology and genomics can merge, not only to guide optimum surgery, but also to provide a more comprehensive portal for precision medicine.

Integrating anatomy, radiology, pathology, and surgery: An alternative approach in resecting multifocal and multicentric breast carcinoma.

The sick lobe hypothesis provides the basis for a lobar approach in radiology, pathology, and surgical treatment of breast cancer. This approach aims to remove the tumor together with the surrounding field of genetic aberrations. Detailed preoperative lobar imaging that properly maps the disease and assesses its extent guides the parenchymal resection. Integration of our knowledge of breast anatomy and pathology with the results of preoperative radiological mapping is critical in assessing the eligibility of patients with multifocal and/or multicentric breast cancer for breast conservation treatment. Through an appropriately selected incision, a multisegment resection of the diseased lobe(s) is performed, which leaves the residual parenchyma in a formation that allows dovetailing of one part into the other, like the way pieces of a jigsaw puzzle fit together. Detailed pathologic analysis of the surgical specimen provides valuable feedback to the radiologist, establishes the completeness of surgical intervention, and generates predictive information for therapeutic decisions. Our approach is a step in continuous search for ideal tailored therapy to avoid under or over-treatment of breast cancer patients.

Ductal Breast Carcinoma In Situ: Mammographic Features and Its Relation to Prognosis and Tumour Biology in a Population Based Cohort.

Casting-type calcifications and a histopathological picture with cancer-filled duct-like structures have been presented as breast cancer with neoductgenesis. We correlated mammographic features and histopathological neoductgenesis with prognosis in a DCIS cohort with long follow-up. Mammographic features were classified into seven groups according to Tabár. Histopathological neoductgenesis was defined by concentration of ducts, lymphocyte infiltration, and periductal fibrosis. Endpoints were ipsilateral (IBE) in situ and invasive events. Casting-type calcifications and neoductgenesis were both related to high nuclear grade, ER- and PR-negativity, and HER2 overexpression but not to each other. Casting-type calcifications and neoductgenesis were both related to a nonsignificant lower risk of invasive IBE, HR 0.38 (0.13-1.08) and 0.82 (0.29-2.27), respectively, and the HR of an in situ IBE was 0.90 (0.41-1.95) and 1.60 (0.75-3.39), respectively. Casting-type calcifications could not be related to a worse prognosis in DCIS. We cannot explain why a more aggressive phenotype of DCIS did not correspond to a worse prognosis. Further studies on how the progression from in situ to invasive carcinoma is driven are needed.

Tumor Deposits in Colorectal Cancer: Improving the Value of Modern Staging-A Systematic Review and Meta-Analysis.

Purpose Colorectal cancer (CRC) treatment is largely determined by tumor stage. Despite improvements made in the treatment of various types of metastatic disease, staging has not been refined. The role of tumor deposits (TDs) in staging remains debated. We have assessed the relation of TDs with metastatic pattern to evaluate whether TDs might add significant new information to staging. Methods We performed a systematic literature search that was focused on the role of TDs in CRC. Studies with neoadjuvant-treated patients were excluded. Data on stage, histologic factors, and outcome were extracted. Data from four large cohorts were analyzed for the relevance of the presence of TDs, lymph node metastases (LNMs), and extramural vascular invasion (EMVI) on the pattern of metastases and outcomes. Results Of 10,106 included patients with CRC, 22% presented with TDs. TDs are invariably associated with poor outcome. Presence of TDs was associated with presence of LNMs and EMVI. In a pairwise comparison, effects of TD were stronger than those of both LNMs and EMVI. In the logistic regression model, TDs in combination with LNMs is the strongest predictor for liver (odds ratio [OR], 5.5), lung (OR, 4.3) and peritoneal metastases (OR, 7.0). Presence of EMVI adds information for liver and lung metastases, but not for peritoneal metastases. Conclusion We have shown that TDs are not equal to LNMs or EMVI with respect to biology and outcome. We lose valuable prognostic information by allocating TDs into nodal category N1c and only considering TDs in the absence of LNMs. Therefore, we propose that the number of TDs should be added to the number of LNMs to derive a final N stage.

Diffuse invasive breast carcinoma of no special type.

Diffuse invasive breast carcinomas are rare tumors associated with unfavorable prognostic parameters. This growth pattern is often related to invasive lobular cancer (ILC). Diffuse ductal breast carcinoma of no special type (NST) is largely under-recognized in the literature. We identified 70 diffuse invasive breast carcinomas in a consecutive series of 1249 invasive tumors. Based on morphology and E-cadherin expression, 15/70 were NST and 55/70 were ILC. Subgroups differed in mammographic appearance, as more NST tumors than ILCs formed stellate masses (53 vs. 18 %, p = 0.000436) while ILCs displayed more architectural distortion. NST tumors were significantly more often radiologically extensive than ILCs (80 vs. 38 %, p = 0.0042987). Subgroups did not differ significantly in disease extent on histology, lymph node status, progesterone receptor status, and molecular phenotype, with a difference of borderline statistical significance in estrogen receptor status (87 vs. 100 %, p = 0.0434783). Significantly more NST tumors were HER2 positive (27 vs. 4 %, p = 0.0050463) and showed high Ki67 proliferation index (60 vs. 25 %, p = 0.0121808). The most striking differences occurred in the histology grade of the in situ (high grade in 53 vs. 4 %) and invasive (high grade in 27 vs. 2 %) tumor components and in the distribution of the in situ component (diffuse in 73 vs. 11 %). We conclude that diffuse invasive breast carcinomas of NST comprise a small subgroup of breast carcinomas. Most of these cancers are non-high grade and of luminal phenotype, but extensive and lymph node positive with worse prognostic parameters than diffuse ILC.

Biobanking multifocal breast carcinomas: sample adequacy with regard to histology and DNA content.

AIMS: To determine the volume of tumoral and normal breast tissue containing sufficient DNA (>2 µg/sample) for genetic platforms and biobanking, with a focus on multifocality, tumoral heterogeneity, and factors that critically influence sample acceptability. METHODS AND RESULTS: We examined 57 breast surgical specimens with multifocal (46/57) and unifocal (11/57) cancers. Punch biopsies were obtained from tissue slices under multimodal radiological guidance, and the colour-coded sampling sites were identified in large-format histology slides. The study comprised 415 DNA isolations from tumour (n = 105) and normal (n = 283) tissue, including skin (n = 27) samples. A single 2-mm core from invasive tumour contained sufficient DNA in 91.4% (96/105) of cases, depending on tumour type (3.8-108.2 µg/sample), number and size of additional foci in multifocal cases (P = 0.001), tumour consistency, and degree of necrosis. Three biopsies obtained with a 4-mm device were required from normal breast tissue, at least 10 mm from the tumour. Cold ischaemia for up to 82 min did not influence the yield of DNA. CONCLUSIONS: Radiological disease mapping is useful for guiding optimal specimen slicing and for targeting breast lesions. A single 2-mm core from tumour and multiple 4-mm cores from normal breast tissue yield adequate DNA in the majority of samples.