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PURPOSE Genomic tests improve accuracy of risk prediction for early breast cancers but these are expensive. This study evaluated the clinical utility of EndoPredict®, in terms of impact on adjuvant therapy recommendations and identification of parameters to guide selective application. METHODS Patients with ER-positive, HER2-negative, and early-stage invasive breast cancer were tested with EndoPredict®. Two cohorts were recruited: one consecutively and another at clinical team discretion. Systemic treatment recommendations were recorded before and after EndoPredict® results were revealed to the multidisciplinary team. RESULTS 233 patients were recruited across five sites: 123 consecutive and 110 at clinical team discretion. In the consecutive cohort 50.6% (62/123) cases were classified high risk of recurrence by EndoPredict®, compared with 62.7% (69/110) in the selective cohort. A change in treatment recommendation was significantly more likely (p

This study aimed to determine the interobserver concordance of two methods for proliferation assessment in breast cancer using Ki67 immunohistochemistry. Ki67 was independently assessed in randomly selected tumour samples from patients with lymph node-negative breast cancer using two different methods: either cell counting or visual estimation of hot spot areas. For hot spot cell counting, positive and negative cell numbers were recorded for total cell counts of 300–500, 500–800 and 800–1000 cells. Visual estimation involved allocation of a score from 1 to 5 using a visual scale to estimate percentage positivity. Interobserver agreement for hot spot counting was calculated using a two-way fixed effects intraclass correlation model, and by using Cohen’s kappa measure for visual assessment. Prognostic concordance between the two methods was also calculated using Cohen’s kappa. Samples from 96 patients were included in this analysis. Interobserver agreement for hot spot cell counting was excellent (> 0.75) across all three cell count ranges, with correlation coefficients of 0.88 (95% CI 0.84–0.92), 0.87 (95% CI 0.82–0.91) and 0.89 (95% CI 0.85–0.92), respectively. Interobserver agreement with visual estimation was greatest for hot spots compared with areas of intermediate or low proliferation, with kappa scores of 0.49, 0.42 and 0.40, respectively. Both assessment methods demonstrated excellent prognostic agreement. Interobserver and prognostic concordance in Ki67 immunohistochemistry assessments was high using either hot spot cell counting or visual estimation, further supporting the utility and reproducibility of these cost-efficient methods to assess proliferation.

Previous research has shown that polygenic risk scores (PRSs) can be used to stratify women according to their risk of developing primary invasive breast cancer. This study aimed to evaluate the association between a recently validated PRS of 313 germline variants (PRS313) and contralateral breast cancer (CBC) risk. We included 56,068 women of European ancestry diagnosed with first invasive breast cancer from 1990 onward with follow-up from the Breast Cancer Association Consortium. Metachronous CBC risk (N = 1,027) according to the distribution of PRS313 was quantified using Cox regression analyses. We assessed PRS313 interaction with age at first diagnosis, family history, morphology, ER status, PR status, and HER2 status, and (neo)adjuvant therapy. In studies of Asian women, with limited follow-up, CBC risk associated with PRS313 was assessed using logistic regression for 340 women with CBC compared with 12,133 women with unilateral breast cancer. Higher PRS313 was associated with increased CBC risk: hazard ratio per standard deviation (SD) = 1.25 (95%CI = 1.18-1.33) for Europeans, and an OR per SD = 1.15 (95%CI = 1.02-1.29) for Asians. The absolute lifetime risks of CBC, accounting for death as competing risk, were 12.4% for European women at the 10th percentile and 20.5% at the 90th percentile of PRS313. We found no evidence of confounding by or interaction with individual characteristics, characteristics of the primary tumor, or treatment. The C-index for the PRS313 alone was 0.563 (95%CI = 0.547-0.586). In conclusion, PRS313 is an independent factor associated with CBC risk and can be incorporated into CBC risk prediction models to help improve stratification and optimize surveillance and treatment strategies. ispartof: AMERICAN JOURNAL OF HUMAN GENETICS vol:107 issue:5 pages:837-848 ispartof: location:United States status: published

Although rare, Metaplastic Breast Carcinomas (MBC) account for significant global breast cancer mortality. This subgroup is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including but not limited to spindle, squamous, chondroid, osseous and rhabdomyoid elements. The WHO working group recognizes that the current classification is inadequate and in the interim, has suggested a purely descriptive classification. The mixed epithelial-mesenchymal morphology has led to speculation that MBC represent 'stem cell tumours'; in support of this, MBC have been shown to have a CD44+/CD24-/low phenotype. Clinically, patients present with tumours that are larger (higher stage), have increased likelihood of distant metastases at presentation and overall, have a reduced 5-year survival rate compared to Invasive Carcinoma-NST. Hence, this is a unique subtype with poor outcome but without a robust classification or understanding of the biology to aid clinical management. We present a detailed morphological, immunohistochemical and genomic analysis of a large series of MBC (n=347), as amassed through the Asia-Pacific MBC consortium. We consider our morphological dissection using the WHO subtyping guidelines and show that an increasing number of phenotypes in a mixed MBC (classified as WHO_1) significantly associates with a poor prognosis. Immunohistochemical analysis showed that a pure spindle (WHO_5) is significantly less likely to express vimentin, CK5/6, CK14, and CK19 than a mixed WHO_1 with spindle features. Similarly, a WHO_1 with chondroid features is less likely to express EGFR than WHO_1 with chondroid features and rhabdoid or osseous differentiation. Across the cohort, positivity for the AE1/3 antibody and a lack of EGFR expression both significantly associate with a better outcome. We report no significant association between patient age at diagnosis and breast cancer specific survival, nor between age and specific WHO MBC subtypes. We report a significant association between WHO_1 types and increasing tumour grade, and also between tumour size and grade, with tumour size being a highly significant prognostic indicator in this cohort. Our exome sequencing confirms a significant enrichment for TP53 and PTEN mutations in MBC, and intriguingly for concurrent mutations of TP53, PTEN and PIK3CA. A novel enrichment for NF1 mutations is also presented. In summary, we provide a thorough assessment of a large cohort of MBC, including morphology, survival, IHC and exome sequencing, and present our analysis contextualized by the WHO guidelines, extending the existing knowledge base of this rare tumour type. Citation Format: McCart Reed AE, Kalaw E, Nones K, Bettington M, Lim M, Bennett J, Johnstone K, Kutasovic JR, Kazakoff S, Xu QC, Saunus JM, Reid LE, Black D, Niland C, Ferguson K, Gresshoff I, Raghavendra A, Liu JC, Kalinowski L, Reid AS, Davidson M, Pearson JV, Yamaguchi R, Harris G, Tse G, Papadimos D, Pathmanathan R, Pathmanathan N, Tan PH, Fox S, O'Toole S, Waddell N, Simpson PT, Lakhani SR. Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-03.

Background Metaplastic breast carcinoma encompasses a heterogeneous group of tumours with differentiation into squamous and/or spindle, chondroid, osseous or rhabdoid mesenchymal-looking elements. Emerging immunotherapies targeting Programmed Death Ligand 1 (PD-L1) and immune-suppressing T cells (Tregs) may benefit metaplastic breast cancer patients, which are typically chemo-resistant and do not express hormone therapy targets. Methods We evaluated the immunohistochemical expression of PD-L1 and FOXP3, and the extent of tumour infiltrating lymphocytes (TILs) in a large cohort of metaplastic breast cancers, with survival data. Results Metaplastic breast cancers were significantly enriched for PD-L1 positive tumour cells, compared to triple-negative ductal breast cancers (P P = 0.0226). Multivariate analysis identified FOXP3 iTILs expression status as an important independent prognostic factor for patient survival. Conclusions Our findings indicate the clinical significance and prognostic value of FOXP3, PD-1/PD-L1 checkpoint and TILs in metaplastic breast cancer and confirm that a subset of metaplastics may benefit from immune-based therapies.

// Timothy Kwang Yong Tay 1 , Aye Aye Thike 1 , Nirmala Pathmanathan 1, 2 , Ana Richelia Jara-Lazaro 1, 3 , Jabed Iqbal 1 , Adeline Shi Hui Sng 1 , Heng Seow Ye 1 , Jeffrey Chun Tatt Lim 1 , Valerie Cui Yun Koh 1 , Jane Sie Yong Tan 1 , Joe Poh Sheng Yeong 1 , Zi Long Chow 1 , Hui Hua Li 4 , Chee Leong Cheng 1 and Puay Hoon Tan 5 1 Department of Anatomical Pathology, Singapore General Hospital, Singapore 2 Current affiliation: Westmead Breast Cancer Institute, Westmead Hospital, Westmead, NSW, Australia 3 Current affiliation: Q 2 Solutions – Central Laboratories, Singapore Science Park One, Singapore 4 Division of Medicine, Singapore General Hospital, Singapore 5 Division of Pathology, Singapore General Hospital, Singapore Correspondence to: Puay Hoon Tan, email: tan.puay.hoon@singhealth.com.sg Keywords: Ki67; breast cancer; computer assisted image analysis; prognosis Received: October 10, 2017 Accepted: January 25, 2018 Published: February 05, 2018 ABSTRACT Background: Ki67 positivity in invasive breast cancers has an inverse correlation with survival outcomes and serves as an immunohistochemical surrogate for molecular subtyping of breast cancer, particularly ER positive breast cancer. The optimal threshold of Ki67 in both settings, however, remains elusive. We use computer assisted image analysis (CAIA) to determine the optimal threshold for Ki67 in predicting survival outcomes and differentiating luminal B from luminal A breast cancers. Methods: Quantitative scoring of Ki67 on tissue microarray (TMA) sections of 440 invasive breast cancers was performed using Aperio ePathology ImmunoHistochemistry Nuclear Image Analysis algorithm, with TMA slides digitally scanned via Aperio ScanScope XT System. Results: On multivariate analysis, tumours with Ki67 ≥14% had an increased likelihood of recurrence (HR 1.941, p=0.021) and shorter overall survival (HR 2.201, p=0.016). Similar findings were observed in the subset of 343 ER positive breast cancers (HR 2.409, p=0.012 and HR 2.787, p=0.012 respectively). The value of Ki67 associated with ER+HER2-PR

Background Axillary reverse mapping (ARM) is a technique used to identify the lymphatics draining the arm. The aim of this study was to examine the prevalence and predictors of ARM node metastases in breast cancer patients undergoing an axillary lymph node dissection (ALND). Methods A total of 87 patients were enrolled in this study. Patent V Blue dye was injected in the upper arm for ARM node localization. All patients had an ALND with the identified ARM node removed and sent separately for histologic analysis. Results Of 67 (77%) patients in whom an ARM node was identified, 49 (73%) were negative and 18 (27%) were positive for metastases on final histopathology. Positive ARM node status was significantly associated with advanced axillary disease, and larger primary cancers. Patients requiring a completion ALND due to a positive sentinel lymph node biopsy (SLNB) with non-suspicious ARM nodes during surgery did not have ARM node metastases. Conclusions There is a high risk of ARM node involvement, approximately a quarter, in patients with preoperatively known lymph node metastases from breast cancer. However, it may be safe to preserve a clinically non-suspicious ARM node in patients with a positive SLNB who require a completion ALND. J. Surg. Oncol. 2016;113:726–731. © 2016 Wiley Periodicals, Inc.

Background The cytomorphological features in the distinction between phyllodes tumour (PT) and fibroadenoma (FA) on fine needle aspiration biopsy (FNAB) remains challenging because of the biphasic nature of these lesions and the rarity of PT. Methods FNAB smears of histologically confirmed PT (N = 26) and FA (N = 78) cases were retrieved from a retrospective database interrogation from the Department of Cytology/Tissue Pathology, ICPMR Pathology West (Cerner Millennium) in Westmead Hospital. For each case, two smears were selected, de-identified and independently reviewed by four observers comprising two cytologists and two cytopathologists. Cytological parameters examined included detailed evaluation of smear cellularity, epithelial and stromal components as well as the smear background. Results The cytological features of moderate to marked stromal cellularity and stromal nuclear atypia were more evident in PT than in FA, identified by three out of four observers. The epithelial characteristics, presence of macrophages, multinucleated giant cells and blood vessels showed no statistically significant differences in the distinction between the two lesions. Conclusion The results of this study indicate that in all of the cytological features assessed for PT and FA, no single cytological feature was found to be statistically significant in identifying PT across all observers. This reflects the overlap of cytological features seen in these lesions. FNAB cytology cannot reliably distinguish FA and PT.

Summary Background We previously reported the 5-year results of the phase 3 IBCSG 23-01 trial comparing disease-free survival in patients with breast cancer with one or more micrometastatic (≤2 mm) sentinel nodes randomly assigned to either axillary dissection or no axillary dissection. The results showed no difference in disease-free survival between the groups and showed non-inferiority of no axillary dissection relative to axillary dissection. The current analysis presents the results of the study after a median follow-up of 9·7 years (IQR 7·8–12·7). Methods In this multicentre, randomised, controlled, open-label, non-inferiority, phase 3 trial, participants were recruited from 27 hospitals and cancer centres in nine countries. Eligible women could be of any age with clinical, mammographic, ultrasonographic, or pathological diagnosis of breast cancer with largest lesion diameter of 5 cm or smaller, and one or more metastatic sentinel nodes, all of which were 2 mm or smaller and with no extracapsular extension. Patients were randomly assigned (1:1) before surgery (mastectomy or breast-conserving surgery) to no axillary dissection or axillary dissection using permuted blocks generated by a web-based congruence algorithm, with stratification by centre and menopausal status. The protocol-specified primary endpoint was disease-free survival, analysed in the intention-to-treat population (as randomly assigned). Safety was assessed in all randomly assigned patients who received their allocated treatment (as treated). We did a one-sided test for non-inferiority of no axillary dissection by comparing the observed hazard ratios (HRs) for disease-free survival with a margin of 1·25. This 10-year follow-up analysis was not prespecified in the trial's protocol and thus was not adjusted for multiple, sequential testing. This trial is registered with ClinicalTrials.gov, number NCT00072293. Findings Between April 1, 2001, and Feb 8, 2010, 6681 patients were screened and 934 randomly assigned to no axillary dissection (n=469) or axillary dissection (n=465). Three patients were ineligible and were excluded from the trial after randomisation. Disease-free survival at 10 years was 76·8% (95% CI 72·5–81·0) in the no axillary dissection group, compared with 74·9% (70·5–79·3) in the axillary dissection group (HR 0·85, 95% CI 0·65–1·11; log-rank p=0·24; p=0·0024 for non-inferiority). Long-term surgical complications included lymphoedema of any grade in 16 (4%) of 453 patients in the no axillary dissection group and 60 (13%) of 447 in the axillary dissection group, sensory neuropathy of any grade in 57 (13%) in the no axillary dissection group versus 85 (19%) in the axillary dissection group, and motor neuropathy of any grade (14 [3%] in the no axillary dissection group vs 40 [9%] in the axillary dissection group). One serious adverse event (postoperative infection and inflamed axilla requiring hospital admission) was attributed to axillary dissection; the event resolved without sequelae. Interpretation The findings of the IBCSG 23-01 trial after a median follow-up of 9·7 years (IQR 7·8–12·7) corroborate those obtained at 5 years and are consistent with those of the 10-year follow-up analysis of the Z0011 trial. Together, these findings support the current practice of not doing an axillary dissection when the tumour burden in the sentinel nodes is minimal or moderate in patients with early breast cancer. Funding International Breast Cancer Study Group.

Ductal carcinoma in situ (DCIS), invasive breast cancer (IBC) and lympho-vascular invasion (LVI) represent distinct stages in breast cancer progression with different clinical implications. Altered microRNA (miRNA) expression may play a role in mediating the progression of DCIS to IBC and LVI. The aim of this pilot study was to investigate whether differential miRNA expression could play a role in breast cancer progression. Cancer cells from DCIS, IBC and LVI were microdissected from formalin fixed paraffin embedded (FFPE) tissue of five breast cancer samples. MiRNA profiling of extracted RNA was performed using the TaqMan® Array Human MicroRNA Cards A and B v3.0. Candidate miRNAs and gene targets were validated by qPCR. 3D culture of MCF10A, MCF10DCIS.com and T47D cells were used as models for normal, DCIS and IBC. Immunohistochemistry of candidate genes was performed on FFPE 3D cell cultures as well as on tissue microarray which included cores of DCIS and IBC samples. MiR-150, miR-126 and miR-155 were found to be more highly expressed in IBC and LVI compared to DCIS. Gene targets of these miRNAs, RhoA, PEG10 and MYB, were found to be more highly expressed in DCIS compared to IBC by qPCR and in MCF10A and MCF10DCIS.com cells compared to T47D cells by immunohistochemistry. There was no difference in intensity of staining of RhoA by immunohistochemistry in DCIS versus IBC samples on tissue microarray. In this pilot study, we found evidence to support a potential role for variation in miRNA levels in the transition from DCIS to IBC.

Background Sentinel lymph node biopsy in breast cancer is a routine technique for staging the axilla. The two most common methods of intraoperative histopathological assessment, imprint cytology and frozen section, are hampered by poor sensitivity and lack standardized methodology. The one-step nuclei acid amplification (OSNA) assay is a rapid quantification of cytokeratin 19 mRNA. This prospective study compared an existing intraoperative imprint cytology protocol with the OSNA system. Methods Of the 110 prospectively recruited patients, 98 met the inclusion criteria with a total of 170 lymph nodes. Intraoperative sentinel nodes were serially sectioned and imprints made of each cut surface for cytological assessment. Alternate slices were submitted for OSNA while the remaining slices were for final histopathological evaluation with six hematoxylin and eosin levels and one AE1/AE3 immunoperoxidase stain of each slice. Results On histopathological analysis, 24.5% of patients (16.5% of nodes) had sentinel node metastases and 3.1% (2.4%) had isolated tumour cells. With isolated tumour cells cases taken as negative, the sensitivity of imprint cytology and OSNA compared with histopathology were 66.7% on patient basis (71.4% on per-node basis) and 95.8% (89.3%), respectively. One of 22 patients with macrometastases and two of three micrometastases were designated negative while five false-positive nodes were identified with OSNA, likely due to tissue allocation bias. Conclusion The OSNA assay is highly sensitive in comparison with imprint cytology and may be used effectively in the intraoperative setting. Clinical follow-up studies are warranted to further assess its use in routine practice.

A 58-year-old lady presented with mediastinal lymphadenopathy. A thoracoscopic ultrasound-guided fine-needle aspiration showed large atypical epithelioid cells arranged in cohesive sheets and dispersed as single cells with intact cytoplasm amid a background of lymphocytes and histiocytes. A cytological diagnosis of "a malignant neoplasm" was made, raising a broad list of differential diagnoses. A broad panel of immunocytochemical stains performed on the cell block was indicative of a lymphoproliferative disorder, but the immunophenotype was intermediate between diffuse large B cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL). Diffuse and strong reactivity to CD20, CD79a, and PAX-5, and weak reactivity to CD30, was in favor of a DLBCL, or more precisely mediastinal (thymic) large B cell lymphoma (MLBL). However, there were negative staining for LCA, OCT-2, and BOB-1 as well as positive staining for EBV-encoded RNA, which were against a diagnosis of MLBL and raised the possibility of cHL. The absence of RS cells and the typical mileu, the negativity for CD15 and the strong positivity of CD20 and PAX-5 were against a diagnosis of cHL. On this basis, the diagnosis of "B-cell lymphoproliferative disorder with features intermediate between DLBCL and cHL" was rendered. The diagnosis was subsequently confirmed on excisional biopsy. This case report demonstrates broad differential diagnoses raised by this diagnostic entity and the importance of an adequate cell block for accurate designation.

Summary Testing for HER2 positivity in breast cancer carries implications for prognosis and therapeutic response in patients. In recent times there have been numerous developments and refinements in the available technologies for HER2 testing. In addition to this, guidelines have been developed and modified in an attempt to improve reliability and accuracy of testing. Immunohistochemistry and FISH testing have been the most widely used methodology, and the technique which has the largest knowledge base. Some of the inherent disadvantages have prompted the development of newer brightfield techniques which overcome some of these issues. There is gathering experience with these emerging technologies. Despite efforts to optimise and standardise procedures there remains a small percentage of cases that continue to be unresolved, whether this be due to issues of polysomy of chromosome 17, other complex genetic changes or analytical/interpretative issues. An ideal method for the resolution of these equivocal results should be considered in a specialised testing/referral centre, and this may include karyotyping studies of chromosome 17 or multiple probes for chromosome 17 using fluorescence in situ hybridisation or multiplex ligation-dependent probe amplification. It is timely to review of some of the newer techniques available for routine testing and approaches for cases which prove difficult to resolve using conventional testing methodology.

The heterogeneity of multiple case breast cancer families that do not carry mutations in BRCA1 or BRCA2 (non-BRCA1/2 families) poses a challenge to the identification of breast cancer susceptibility genes. The aim of this study was to determine whether intrafamilial concordance in breast cancer pathology could identify subgroups of non-BRCA1/2 families with consistent genotypic features. Invasive breast cancers were reviewed from 84 individuals belonging to 30 multiple-case families; BRCA1 (n = 9), BRCA2 (n = 10), and non-BRCA1/2 (n = 11). Hierarchical cluster analysis based on histopathology and age at first diagnosis was then used to specify three subgroups designated Clusters 1-3. The genomic features of non-BRCA1/2 families were examined by genome wide linkage and FGFR2 SNP genotyping, according to whether they showed cluster-concordant or cluster-mixed familial pathology. The majority of pathogenic BRCA1 mutation carriers (80%) fell into a single cluster. In contrast pathogenic BRCA2 mutation carriers were distributed across all three clusters and within families, cluster groups were also generally mixed. Most non-BRCA1/2 mutation carriers belonged to Cluster 3 (71%). Genome wide linkage data from five non-BRCA1/2 Cluster 3-concordant families were compared with four mixed cluster non-BRCA1/2 families. This revealed a number of distinct linkage peaks, including some regions previously associated with breast cancer susceptibility. The distribution of low risk alleles in FGFR2 was not different between these two subgroups (P = 0.237). The pattern of breast cancer pathology concordance amongst family members may assist the investigation of breast cancer susceptibility in multiple case families.

The management of asymptomatic intraductal papillary lesions of the breast diagnosed on core biopsy poses a challenge for patients and clinicians, as the distinction between common benign lesions and atypical or malignant varieties may be difficult without formal excision. The aim of this study was to determine whether a combination of histopathologic and biomarker features could be used to accurately identify benign papillary lesions on core biopsy. An inclusive group of 127 excised papillary lesions was characterized by detailed histopathologic review and immunohistochemical staining for the basal markers cytokeratin 5/6 (CK5/6) and P63 and the proliferation marker Ki67. Comparison of benign, atypical, and malignant lesions revealed that the combination of broad, sclerotic fibrovascular cores, and epithelial CK5/6 staining was most commonly seen in benign papillomas. Ki67 staining revealed striking intralesional heterogeneity, but there was no difference between the high scores of benign, atypical, or malignant lesions (P=0.173). In a non-overlapping set of 42 cases, a binary classifier specifying benign lesions on the basis of thick fibrovascular cores and epithelial CK5/6 staining on core biopsy gave an overall misclassification rate of 4/42 (10%) when compared with the final excision diagnosis. Misclassified cases included 2/27 lesions ultimately diagnosed as benign and 2/2 atypical papillomas. All malignant lesions (n=13) were correctly assigned. The combined assessment of fibrovascular core thickness and CK5/6 staining on core biopsy distinguished benign from malignant papillary lesions, but did not separate benign from atypical cases. This approach may form a useful addition to the clinicopathologic evaluation of papillary lesions of the breast.

Columnar cell lesions (CCLs) of the breast have been increasingly recognised in biopsies taken to investigate mammographic screen detected microcalcification. The aim of this study was to identify distinct CCL subtypes by systematic analysis of histopathology.Hierarchical cluster analysis was performed based on the profile of histopathological features in 102 screen detected CCLs. Features assessed included nuclear morphology, acinar dilatation, epithelial cell hyperplasia, cell crowding, apical snout formation and intraluminal secretion. The stability of this classification was tested in an independent cohort of 32 cases.The histopathology of screen detected CCLs was extremely variable. Hierarchical cluster analysis identified two subclasses: Class 1 (34/102, 33%) characterised by absence of nuclear atypia and less pronounced hyperplasia; and Class 2 (68/102, 67%) that were generally more atypical. Ki-67 scores were significantly lower for Class 1 CCLs (p0.001). In the independent cohort of 32 cases, Class 1 cases were clearly distinguished from Class 2, indicating that these were stable phenotypes amongst screen detected CCLs.The histopathological features of CCLs diagnosed at screening are extremely heterogeneous. Using a systematic approach, we have devised a broad classification system that delineates a category of less atypical CCLs that could form a basis for future studies.

With the emergence of multiple lines of highly effective Human Epidermal Growth Factor Receptor 2 (HER2) directed therapy, accurate identification of HER2 positive tumour has become a critical aspect in the histopathological analysis of breast cancers. Multifocal invasive breast carcinomas are relatively common, and given the aggressive inherent biology of HER2 positive disease, identification of even small tumours with HER2 positive status may be of importance for treatment planning. There are currently no clear guidelines as to whether all of these foci should be tested for HER2 status. We reviewed the results of 172 patients in whom HER2 in situ hybridisation (ISH) testing was performed on at least two ipsilateral synchronous invasive carcinomas. Discordant results in different invasive foci were relatively uncommon and occurred in only eight (5%) of the 172 patients. This showed a statistically significant correlation with similarly discordant oestrogen receptor (ER) results. In addition HER2 discordance was more likely amongst different tumour foci if these arose in distinct and separate areas of DCIS. An algorithm based on a combination of College of American Pathologists (CAP) recommendation for HER2 testing, differing ER status and background DCIS profile may be useful in detecting these discordant cases.

Aim Current estimates of the human epidermal growth factor receptor 2 (HER2)-positivity rate in gastric cancer vary widely in the literature, and there are limited data from countries in Asia. The primary aim of this study was to conduct a clinical audit of laboratories across seven countries in Asia to determine the incidence of HER2-positive gastric cancer in this region. Methods Pathologists were asked to collect data on patient gender, age, cancer site, specimen type, tumor spread, type and grade, HER2 test results, including protein and/or gene copy enumeration, and final HER2 status on consecutive gastric cancer cases tested for HER2 in their laboratory over a 2-year period. Results HER2 results from 5,301 gastric cancers were submitted by 50 laboratories. The overall HER2-positivity rate was 9.7% which, after the exclusion of China, increased to 18.1%. The rate between countries ranged from 0% to 23.1%, and from 0% to 50.0% between laboratories. An equivocal HER2 result was recorded in 19.5% of cases. Conclusion Despite the lack of centralized testing to confirm the accuracy of HER2 diagnoses, the incidence of HER2-positive gastric cancer observed here was comparable to that reported in the literature. Nevertheless, rates were highly variable between countries and laboratories, which suggests a lack of HER2 testing expertise in gastric cancer. Given that the mortality rates for gastric cancer in Eastern Asia are the highest in the world, efforts should focus on improving HER2 testing expertise in the region so that patients receive the appropriate treatment early in their disease.

Background Breast carcinomas composed predominantly or exclusively of cells with foamy and/or granular cytoplasm have been teamed histiocytoid breast carcinoma (HBC). Cases Three cases of HBC had fine needle aspirates that were moderately cellular and composed of cells with abundant foamy and/or granular cytoplasm, arranged in loosely cohesive groups and dispersed singly. The cells shirked subtle cytologic atypia, including nuclear hyperchromasia and slightly irregular nuclear outlines. Definitive cytologic diagnosis was not possible in the ) cases, and they were reported as "suspicions for malignancy." Core biopsies of 2 cases showed a typical Indian file pattern of invasive lobular carcinoma, while the third case was composed of sheets of discohesive histiocytoid cells admixed with a prominent lymphoid infiltrate. All 3 cases were E-cadherin negative, confirming their lobular nature. Conclusion HBC represents an unusual morphologic pattern of apocrine change that may be seen in lobular and ductal breast carcinomas. Recognition of these lesions is vital in that they may he mistaken for a variety of other entities composed of foamy/granular cells; some of those entities have vastly different implications for treatment and prognosis.

Aim To evaluate the utility of Ki67 as a prognostic marker in a series of patients with node-negative breast cancer untreated with adjuvant systemic therapy. Methods The cohort consisted of 203 cases treated with breast conserving surgery and radiation only; median follow-up was 183 months (range 156–277 months). An immunohistochemical panel of oestrogen receptor (ER), progesterone receptor (PR), cytokeratin (CK)5/6 and Ki67 and human epidermal growth factor 2 in situ hybridization (HER2-ISH) was performed on the tumour samples. Ki67 scores were evaluable in 193/203 patients (95.1%). The primary outcome was breast cancer specific survival (BCSS). Results Of the cohort, 29 (14.2%) died of breast cancer. A cut off of 10% separated tumours into a ‘Ki67-low’ (n=70) or ‘Ki67-high’ group (n=123). The breast cancer specific survival was 97.1% and 77.6% for Ki67-low and Ki67-high groups, respectively. Univariate analysis showed that in this lymph node-negative cohort, the predictors for BCSS were tumour size, Ki67, LVI, age and histological grade 3. Multivariable analysis showed that Ki67 index and lymphovascular space invasion were independent predictors of breast cancer death. To examine the utility of Ki67 in assignment of immunohistochemically molecular subtypes, cases were assigned into Luminal A (ER-positive, HER2-negative, Ki67 ≤14%), Luminal B (ER-positive, HER2-negative, Ki67 >14%) and triple negative (ER/PR-negative and HER2-negative, any Ki67). The 15-year breast cancer specific survival was 91.7%, 79.4% and 75.8%, respectively. Conclusions A statistically significant difference in breast cancer specific survival is seen in groups defined using Ki67 and receptor status, whereas histological grading was not a significant predictor of survival. Ki67 immunostaining provides prognostic information beyond traditionally assessed clinicopathological variables.

Triple-negative (TN) breast cancer is an aggressive subtype of breast cancer associated with a unique set of epidemiologic and genetic risk factors. We conducted a two-stage genome-wide association study of TN breast cancer (stage 1: 1529 TN cases, 3399 controls; stage 2: 2148 cases, 1309 controls) to identify loci that influence TN breast cancer risk. Variants in the 19p13.1 and PTHLH loci showed genome-wide significant associations (P < 5 × 10(-) (8)) in stage 1 and 2 combined. Results also suggested a substantial enrichment of significantly associated variants among the single nucleotide polymorphisms (SNPs) analyzed in stage 2. Variants from 25 of 74 known breast cancer susceptibility loci were also associated with risk of TN breast cancer (P < 0.05). Associations with TN breast cancer were confirmed for 10 loci (LGR6, MDM4, CASP8, 2q35, 2p24.1, TERT-rs10069690, ESR1, TOX3, 19p13.1, RALY), and we identified associations with TN breast cancer for 15 additional breast cancer loci (P < 0.05: PEX14, 2q24.1, 2q31.1, ADAM29, EBF1, TCF7L2, 11q13.1, 11q24.3, 12p13.1, PTHLH, NTN4, 12q24, BRCA2, RAD51L1-rs2588809, MKL1). Further, two SNPs independent of previously reported signals in ESR1 [rs12525163 odds ratio (OR) = 1.15, P = 4.9 × 10(-) (4)] and 19p13.1 (rs1864112 OR = 0.84, P = 1.8 × 10(-) (9)) were associated with TN breast cancer. A polygenic risk score (PRS) for TN breast cancer based on known breast cancer risk variants showed a 4-fold difference in risk between the highest and lowest PRS quintiles (OR = 4.03, 95% confidence interval 3.46-4.70, P = 4.8 × 10(-) (69)). This translates to an absolute risk for TN breast cancer ranging from 0.8% to 3.4%, suggesting that genetic variation may be used for TN breast cancer risk prediction.

New approaches to the prognostic assessment of breast cancer have come from molecular profiling studies. A major feature of this work has been to emphasise the importance of cancer cell proliferation as a key discriminative indicator of recurrence risk for oestrogen receptor positive breast cancer in particular. Mitotic count scoring, as a component of histopathological grade, has long formed part of a routine evaluation of breast cancer biology. However, there is an increasingly compelling case to include a specific proliferation score in breast cancer pathology reports based on expression of the cell cycle regulated protein Ki67. Immunohistochemical staining for Ki67 is a widely available and economical test with good tolerance of pre-analytical variations and staining conditions. However, there is currently no evidence based protocol established to derive a reliable and informative Ki67 score for routine clinical use. In this circumstance, pathologists must establish a standardised framework for scoring Ki67 and communicating results to a multidisciplinary team.

The aim of this study was to determine the impact of universal HER2 testing on the clinico-pathologic profile of HER2+ breast cancer. Data were extracted from breast cancer pathology reports spanning two periods: before (2003/4, n = 379), and after (2008/9, n = 560) the introduction of universal testing. In 2003/4, 43.3% of breast cancers were tested for HER2 with 16% of tested cases HER2+. In 2008/9, 98.4% of cases were tested with 14.7% HER2+. In 2008/9, HER2+ status was associated with younger age, higher grade, increased tumour size, lymph node involvement, negative oestrogen and/or progesterone receptor status. HER2+ cases diagnosed in 2003/4 were not significantly different in respect of these features. The rate of HER2+ breast cancer amongst screen detected cases in 2008/9 was 8.3%. The phenotype of HER2+ breast cancer was stable following the introduction of universal testing. The overall rate of HER2+ breast cancer was influenced by screen detection.

The initial 18 months experience of performing intraoperative imprint cytology for patients with breast cancer undergoing sentinel lymph node biopsy is described for a single institution. The learning process is compared with published results from institutions with many years of experience in order to assess progress in reaching those ideal results, and the methodology used by these institutions is reviewed.A retrospective review was undertaken of the intraoperative imprint cytology results from 103 patients with breast cancer (yielding a total of 170 lymph nodes) who underwent imprint cytology of their sentinel lymph node. The intraoperative imprint cytology results were compared with the final histopathological results. Details regarding the primary tumour characteristics and metastatic deposit size were recorded.The sensitivity for imprint cytology was 31.1%, with a specificity of 100% and overall accuracy of 77.8%. The sensitivity for detecting macrometastases (2 mm diameter) was 61.9% and the sensitivity for micrometastases (2 mm diameter) and including isolated tumour cells was 4.2%.The differences in sensitivity in comparison with many studies in the literature are multifactorial, and include technical aspects, such as the methodology used in the final histopathological and intraoperative evaluation of the sentinel lymph nodes, interpretative difficulties, and much lower case numbers. Furthermore, these numbers represent early experience and methods to improve sensitivity and overall accuracy are detailed in this paper.

Purpose To examine the prognostic value of lymph node ratio (LNR) for patients with node-positive breast cancer with varying numbers of minimum nodes removed (>5, > 10 and > 15 total node count). Methods This study examined the original histopathological reports of 332 node-positive patients treated in the state of New South Wales (NSW), Australia between 1 April 1995 and 30 September 1995. The LNR was defined as the number of positive lymph nodes (LNs) over the total number of LNs removed. The LNR cutoffs were defined as low-risk, 0.01–0.20; intermediate-risk, 0.21– 0.65; and high-risk, LNR >0.65. Results The median follow-up was 10.3 years. In multivariate analysis, LNR was an independent predictor of 10-year breast cancer specific survival when > 5 nodes were removed. However, LNR was not an independent predictor when > 15 nodes were removed. In a multivariate analysis the relative risk of death (RR) decreased from 2.20 to 1.05 for intermediate-risk LNR and from 3.07 to 2.64 for high-risk while P values increased from 0.027 to 0.957 for intermediate-risk LNR and 0.018 to 0.322 for high-risk with the number of nodes removed increasing from > 5 to > 15. Conclusions Although LNR is important for patients with low node denominators, for patients with macroscopic nodal metastases in several nodes following an axillary dissection who have more than 15 nodes dissected, the oncologist can be satisfied that prognosis, selection of adjuvant chemotherapy and radiotherapy fields can be based on the numerator of the positive nodes. Electronic supplementary material The online version of this article (doi:10.1186/s40064-015-0865-2) contains supplementary material, which is available to authorized users.