Second opinion (external specialist referral) practice of breast pathology: the Nottingham experience.

AIMS: Breast pathology is a challenging field, and discrepancies in diagnoses exist and can affect patient management. This study aims to review a breast referral practice and assess the pattern and frequency of breast lesions sent for an external expert review and evaluate potential impacts on patients' care. METHODS AND RESULTS: Seven hundred and forty cases that were referred to Nottingham City Hospital for a second opinion between 2019 and 2022 which have slides and reports were retrieved and reviewed. Reasons for referral, initial diagnosis, proffered specialist opinion and any discrepancy or potential impacts of management were assessed. The most frequent entities were papillary lesions (19%), fibroepithelial lesions (17%), invasive carcinomas that were sent for confirmation of the invasive diagnosis or subtyping of the invasive tumour (17%), intraductal epithelial proliferation with atypia (9%) and spindle cell lesions (8%). Other entities included biphasic tumours such as adenomyoepithelioma, as well as vascular and nipple lesions. Few cases were sent for prognostic classification or comments on the management, and in occasional cases no initial diagnosis was offered. After reviewing the cases by the expert pathologists, the initial diagnosis was confirmed or one of the suggested diagnoses was preferred in 79% of cases, including 129 cases (17%) in which the opinion resulted minor changes in the management. Significant changes in the classification of lesions were made in 132 cases (18%) which resulted in significant change in the patient management recommendation. In 14 cases (2%) a final classification was not possible, and further specialist opinion was obtained. Comments on the differential diagnosis and advice on further patient management were provided in most cases. CONCLUSIONS: This study demonstrates the value of external referral of challenging, rare and difficult to classify breast lesions. It also highlights the most common breast lesions that are likely to be challenging, and specialist opinion can refine their classification to improve patient care.

Preoperative diagnosis of ductal carcinoma in situ of the breast over a 24-year period.

AIMS: The method of diagnosis of ductal carcinoma in situ (DCIS) has changed since the 1980s. The aim of this audit was to assess changes in the preoperative diagnosis of DCIS since the introduction of needle core biopsy, particularly the proportion with a preoperative biopsy diagnosis of DCIS. METHODS AND RESULTS: The preoperative diagnoses of patients with a final diagnosis of DCIS in the surgical specimen were reviewed (i) in 809 patients who presented through breast screening from 1997 to 2021, and (ii) in all patients in 5 individual years at 5-year intervals from 2000 to 2020 (254 in total). For screening-detected DCIS the proportion with a preoperative diagnosis of DCIS increased from 75% to 98% over the study period. In a detailed analysis of all cases of DCIS in 5 separate years the proportion with a preoperative diagnosis of DCIS increased from 68% in 2000 to 96% in 2020. For high-grade DCIS the proportion increased from 87% to 97%, and for low- or intermediate-grade DCIS from 48% to 93%. The proportion of women who had vacuum-assisted biopsy increased from 7% in 2000 to 58% in 2015. There was a small increase in the number of biopsies that had basal cytokeratin and oestrogen receptor immunohistochemistry to aid diagnosis. CONCLUSION: There has been an increase in the preoperative diagnosis of DCIS, particularly of low- or intermediate-grade, over the last two decades. The increasing use of vacuum-assisted biopsy is likely to be a major contributory factor to this increase.

Correlations of morphological features and surgical management with clinical outcome in a multicentre study of 241 phyllodes tumours of the breast.

AIMS: Phyllodes tumours (PTs) represent an unusual but complex group of breast lesions with a tendency to recur locally and, less commonly, metastasise. On core biopsies, their appearances can be difficult to discriminate from those of other fibroepithelial lesions, which may compromise their surgical management. The aims of this study were to assess the preoperative diagnosis of PTs and to evaluate the impacts of surgical management and morphological features on their behaviour. METHODS AND RESULTS: We combined datasets from three centres over two decades, including core biopsies, excision specimens, and follow-up. Core biopsy results were compared with final excision specimens. The relationships of surgical procedure and morphological features with local recurrence (LR) and metastasis were assessed. Two hundred and forty-one PTs were studied. Core biopsy resulted in a diagnosis of possible or definite PT in 76% of cases. Malignant tumours were more likely to be larger, occurred at an older age, and were surgically more challenging, with difficulties being encountered in achieving negative margins. There were 12 cases (5%) that showed LR alone, and another six cases (2.5%) that had distant metastases. Morphological features associated with adverse outcome were grade of PT, increased mitotic counts, necrosis, infiltrative margins, stromal atypia, and heterologous components. Both LR and metastatic behaviour correlated with larger size and distance to margins. CONCLUSIONS: Our results suggest that excision margins have a significant impact on LR of PT, whereas metastatic behaviour is influenced by tumour biology. We add to the evidence base on histological features of tumours that contribute to long-term outcomes of PT patients.

Histological clues to the diagnosis of metastasis to the breast from extramammary malignancies.

AIMS: The aims of this study were to review the histological features useful for the identification of metastases to the breast and to investigate the impression that this diagnosis has become more common. METHODS AND RESULTS: The histological features of metastases to the breast from 2008 to 2018 were reviewed. Seventy-four biopsies from 66 patients were identified: 1% compared with primary carcinoma of the breast. Non-haematological metastases comprised 0.75% compared with 0.3% in a series from 1996 to 2005. The most common tumour types were pulmonary carcinoma (22), lymphoma (15), melanoma (13), gastrointestinal carcinoma (eight) and serous papillary carcinoma (four). In 73% there were histological features that were not typical of primary mammary carcinoma. Some metastases were histologically similar to breast cancer and the history was essential to making the correct diagnosis. Useful histological clues included small-cell morphology for pulmonary carcinoma, glands containing necrosis for gastrointestinal carcinoma, intranuclear inclusions, marked pleomorphism and spindle cells for melanoma, clear cells for renal carcinoma, papillary architecture for serous papillary carcinoma and sheets of centroblasts or nodules of centroblasts and centrocytes for lymphoma. Useful immunohistochemical markers included TTF-1 for pulmonary carcinoma, S100, melan-A and HMB45 for melanoma, CK20 and CDX2 for colorectal carcinoma, PAX8 and WT1 for serous papillary carcinoma and lymphoid markers for lymphomas, in addition to the absence of expression of mammary markers ER, GATA3 and GCDFP-15. CONCLUSION: The majority of metastases to the breast have histological clues to the diagnosis. Immunohistochemistry is helpful. This diagnosis is being made more frequently.

Defining a threshold for tacrolimus intra-patient variability associated with late acute cellular rejection in paediatric kidney transplant recipients.

BACKGROUND: Late acute cellular rejection (LACR) is associated with poorer graft outcomes and non-adherence. Non-adherence to tacrolimus can be indirectly assessed by the intra-patient variability (IPV) of tacrolimus trough levels. The threshold of IPV associated with rejection is not known. METHODS: We conducted a case-control study comparing 25 patients with biopsy-proven LACR against 25 stable controls matched for age group, primary diagnosis and time post-transplant. IPV was calculated using coefficient of variance (CV) and mean absolute deviation (MAD) using tacrolimus levels in the preceding 12 months. We also assessed the percentage time for tacrolimus levels < 4 µg/L (Tac < 4) and the concentration/weight-adjusted dose (C/D) ratio as a proxy marker of tacrolimus metaboliser status. RESULTS: LACR patients had higher CV (median, IQR 44%, 36-61% v. 24%, 19-35%, p < 0.0001) and higher MAD (33%, 25-48% v. 19%, 15-26%, p < 0.0001). The MAD was less affected by outlying tacrolimus results. Receiver operating curve analysis of the MAD resulted in a sensitivity of 76% and specificity of 76% at a threshold of 26% (AUC 0.85, p < 0.05). LACR patients had more Tac < 4 (50% v. 26%, p < 0.05). There was no difference in C/D suggesting that good IPV can be maintained in fast metabolisers. Patients with LACR had significantly increased creatinine at 12-month follow-up despite treatment (108 v. 5 umol/L increase from baseline) and four patients lost their allograft. CONCLUSIONS: Monitoring of tacrolimus IPV using the MAD may be a clinical marker for LACR. A threshold IPV of 26% can potentially be used as a therapeutic target pending further validation studies.

Immunoprofile of metaplastic carcinomas of the breast.

AIMS: Metaplastic breast carcinoma (MBC) is a rare type of breast cancer; its diagnosis in routine practice can be challenging, and may require immunohistochemical (IHC) characterization if no conventional invasive or in-situ carcinoma is present. Previous IHC studies of MBC often had a small sample size and did not investigate the different histological subtypes. This study aimed to assess the immunoprofile of MBC subtypes in a large series. METHODS AND RESULTS: A total of 172 MBC diagnosed in routine and referral practice in Nottingham during 26 years were reviewed by three breast pathologists. In addition, data on the immunoprofile of 730 MBC in 61 published studies were analysed. The antibodies to a broad spectrum of cytokeratins (AE1/AE3 and MNF116) are most frequently positive in MBC (approximately 80%). Basal cytokeratins (34ßE12, CK5/6, CK14 and CK17) are positive in approximately 70%. Luminal cytokeratins (CK8/18, CK7 and CK19) are positive in approximately 30-60%. Myoepithelial markers are also frequently positive, particularly p63. Oestrogen receptor (ER), progestogen receptor (PR) and HER2 are usually all negative. CD34 (a marker often positive in phyllodes tumours) is consistently negative in MBC. CONCLUSION: This study provides data on the frequency of expression of a wide range of markers in MBC based on a large number of tumours. No consistent immunophenotype was identified and no individual marker was positive in all tumours, most probably reflecting the morphological and molecular heterogeneity of this tumour class and the practical need to use a panel of different antibodies when trying to establish the diagnosis of metaplastic breast carcinoma.

Diagnostic concordance of breast pathologists: lessons from the National Health Service Breast Screening Programme Pathology External Quality Assurance Scheme.

AIMS: Previous concordance studies examining accuracy of breast diagnosis by pathologists, typically targeting difficult, histologically challenging breast lesions using artificial and restrictive environments, have reported aberrantly high levels of diagnostic discordance. The results of these studies may be misinterpreted by non-pathologists and raise concerns relating to routine practice. This study aims to assess the diagnostic agreement among UK breast pathologists. METHODS: Two hundred and forty consecutive breast lesions, submitted by participants from their routine practice, included in the UK National Health Service Breast Screening Programme (NHSBSP) breast pathology EQA scheme during the last 10 years were reviewed. An average of approximately 600 participants viewed each case. Data on diagnostic categories (benign, atypical, in-situ malignant and invasive malignant) were collected. In this study, benign and atypical diagnoses were grouped together. RESULTS: The overall diagnostic agreement level was in the almost perfect range. Thirty-five cases (14.6%) showed diagnostic concordance of ≤95%. Reasons for discordance included one or more of: (1) scheme methodology limitations such as: (i) miscoding of certain lesions (e.g. phyllodes tumours and lobular neoplasia) (n = 7) and (ii) variable representation of the index lesion on glass slides (n = 18); and (2) diagnostically challenging cases that may be interpreted more easily using immunohistochemistry (n = 28). These latter included benign and malignant papillary lesions (n = 12), complex sclerosing lesions (n = 7), intraductal epithelial proliferative lesions (n = 6) and an unusual special tumour type (n = 1). Further review identified pathologists' misinterpretation in 13 cases (5.4%), with an average discordance rate of only 4.2%. CONCLUSIONS: The performance of breast pathologists is high. Exclusion of the effect of the scheme methodology limitations highlights further the high performance rate and identifies true diagnostically challenging entities. These difficult cases may benefit from additional diagnostic work-up and second opinions.

Pleomorphic adenoma-like tumour of the breast.

AIMS: Pleomorphic adenoma (PA) of the breast is a rare tumour seen usually in postmenopausal women. Although PA of the salivary glands (SG) is recognized to be a benign tumour, the nature and biology of similar tumours seen in the breast remains to be defined. The aim of this study was to describe PA of the breast that was reported on core biopsy as an invasive matrix-producing metaplastic breast carcinoma (MBC). METHODS AND RESULTS: A core biopsy from a clinically malignant retroareolar mass showed mildly atypical polygonal cells with surrounding myxoid stroma. Immunohistochemistry showed expression of basal and luminal cytokeratins, but oestrogen receptor, human epidermal growth factor receptor 2 (HER2) and myoepithelial markers were negative. The excision specimen showed similar features, but in addition the stroma showed cartilage and bone. Also it was clear that the lesion was circumscribed and merged with a sclerosed papillary lesion consistent with what has been described as mammary PA. CONCLUSION: This lesion shows an overlap of morphology and immunophenotype with SG-PA and with MBC. The majority of mammary PAs have a benign behaviour, but local recurrence and development of carcinoma occur. We propose a new terminology of pleomorphic adenoma-like tumour of the breast to reflect the uncertain nature of these tumours and help guide management decisions.

Breast lesions of uncertain malignant nature and limited metastatic potential: proposals to improve their recognition and clinical management.

Breast lesions comprise a family of heterogeneous entities with variable patterns of presentation, morphology and clinical behaviour. The majority of breast lesions are classified traditionally into benign and malignant conditions and their behaviour can, in the vast majority of cases, be predicted with a reasonable degree of accuracy. However, there remain lesions which show borderline features and lie in a grey zone between benign and malignant, as their behaviour cannot be predicted reliably. Defined pathological categorization of such lesions is challenging, and for some entities is recognized to be subjective and include a range of diagnoses, and forms of terminology, which may trigger over- or undertreatment. The rarity of these lesions makes the acquisition of clinical evidence problematic and limits the development of a sufficient evidence base to support informed decision-making by clinicians and patients. Emerging molecular evidence is providing a greater understanding of the biology of these lesions, but this may or may not be reflected in their clinical behaviour. Herein we discuss some breast lesions that are associated with uncertainty regarding classification and behaviour, and hence management. These include biologically invasive malignant lesions associated with uncertain metastatic potential, such as low-grade adenosquamous carcinoma, low-grade fibromatosis-like spindle cell carcinoma and encapsulated papillary carcinoma. Other lesions of uncertain malignant nature remain, such as mammary cylindroma, atypical microglandular adenosis, mammary pleomorphic adenoma and infiltrating epitheliosis. The concept of categories of (1) breast lesions of uncertain malignant nature and (2) breast lesions of limited metastatic potential are proposed with details of which histological entities could be included in each category, and their management implications are discussed.

The repertoire of somatic genetic alterations of acinic cell carcinomas of the breast: an exploratory, hypothesis-generating study.

Acinic cell carcinoma (ACC) of the breast is a rare form of triple-negative (that is, oestrogen receptor-negative, progesterone receptor-negative, HER2-negative) salivary gland-type tumour displaying serous acinar differentiation. Despite its triple-negative phenotype, breast ACCs are reported to have an indolent clinical behaviour. Here, we sought to define whether ACCs have a mutational repertoire distinct from that of other triple-negative breast cancers (TNBCs). DNA was extracted from microdissected formalin-fixed, paraffin-embedded sections of tumour and normal tissue from two pure and six mixed breast ACCs. Each tumour component of the mixed cases was microdissected separately. Tumour and normal samples were subjected to targeted capture massively parallel sequencing targeting all exons of 254 genes, including genes most frequently mutated in breast cancer and related to DNA repair. Selected somatic mutations were validated by targeted amplicon resequencing and Sanger sequencing. Akin to other forms of TNBC, the most frequently mutated gene found in breast ACCs was TP53 (one pure and six mixed cases). Additional somatic mutations affecting breast cancer-related genes found in ACCs included PIK3CA, MTOR, CTNNB1, BRCA1, ERBB4, ERBB3, INPP4B, and FGFR2. Copy number alteration analysis revealed complex patterns of gains and losses similar to those of common forms of TNBCs. Of the mixed cases analysed, identical somatic mutations were found in the acinic and the high-grade non-acinic components in two out of four cases analysed, providing evidence of their clonal relatedness. In conclusion, breast ACCs display the hallmark somatic genetic alterations found in high-grade forms of TNBC, including complex patterns of gene copy number alterations and recurrent TP53 mutations. Furthermore, we provide circumstantial genetic evidence to suggest that ACCs may constitute the substrate for the development of more aggressive forms of triple-negative disease.

Are acinic cell carcinomas of the breast and salivary glands distinct diseases?

AIMS: Acinic cell carcinomas (AcCC) of the breast have been reported to constitute the breast counterpart of salivary gland AcCCs, based on the similarities of their histological and immunohistochemical features. Breast AcCC is a vanishingly rare form of triple-negative breast cancer (TNBC). Recent studies have demonstrated that in TNBCs, the two driver genes most frequently mutated are TP53 (82%) and PIK3CA (10%). We sought to define whether breast AcCCs would harbour TP53 and PIK3CA somatic mutations, and if so, whether these would be present in salivary gland AcCCs. METHODS AND RESULTS: Sanger sequencing of the entire coding region of TP53 and of PIK3CA hotspot mutation sites of 10 breast and 20 salivary gland microdissected AcCCs revealed eight TP53 (80%) and one PIK3CA (10%) somatic mutations in breast AcCCs. No somatic mutations affecting these genes were found in the 20 salivary gland AcCCs analysed. CONCLUSIONS: Our findings demonstrate that breast AcCCs display TP53 and PIK3CA mutations at frequencies similar to those of common types of TNBCs, whereas these genes appear not to be altered in salivary gland AcCCs, suggesting that despite their similar histological appearances, AcCCs of the breast and salivary glands probably constitute unrelated diseases.

Breast Neoplasms with Dermal Analogue Differentiation (Mammary Cylindroma): Report of 3 Cases and a Proposal for a New Terminology.

Salivary gland-like and dermal analogue tumours of the breast are rare lesions that can be diagnostically challenging for pathologists. Data on the clinical behaviour and molecular characterisation of these mammary tumours are limited and their designation is mainly based on similar salivary gland or skin lesions. In this study, we present three cylindromatous breast tumours. These lesions were located within the breast, had ill-defined margins and were composed of nests containing a dual population of cytologically bland cells, surrounded at least partially by basement membrane-like material. The lack of cytological atypia and absence of mitoses led to the diagnosis of benign mammary cylindroma in 1 case. The expression of oestrogen receptor, focal absence of basement membrane material and the focal infiltrative nature together with patchy absence of peripheral basement membrane supported the diagnosis of malignancy in the other 2 cases. We discuss the morphological criteria, immunohistochemical profile and diagnostic pitfalls of these tumours. We also review the literature including previously reported cases of mammary cylindroma and differential diagnoses to be considered before making a diagnosis. We propose the term 'mammary tumours with cylindromatous differentiation', implying their uncertain malignant nature, and propose management strategies.

Remote conditioning or erythropoietin before surgery primes kidneys to clear ischemia-reperfusion-damaged cells: a renoprotective mechanism?

Acute kidney injury is common, serious with no specific treatment. Ischemia-reperfusion is a common cause of acute kidney injury (AKI). Clinical trials suggest that preoperative erythropoietin (EPO) or remote ischemic preconditioning may have a renoprotective effect. Using a porcine model of warm ischemia-reperfusion-induced AKI (40-min bilateral cross-clamping of renal arteries, 48-h reperfusion), we examined the renoprotective efficacy of EPO (1,000 iu/kg iv.) or remote ischemic preconditioning (3 cycles, 5-min inflation/deflation to 200 mmHg of a hindlimb sphygmomanometer cuff). Ischemia-reperfusion induced significant kidney injury at 24 and 48 h (χ(2), 1 degree of freedom, >10 for 6/7 histopathological features). At 2 h, a panel of biomarkers including plasma creatinine, neutrophil gelatinase-associated lipocalin, and IL-1ß, and urinary albumin:creatinine could be used to predict histopathological injury. Ischemia-reperfusion increased cell proliferation and apoptosis in the renal cortex but, for pretreated groups, the apoptotic cells were predominantly intratubular rather than interstitial. At 48-h reperfusion, plasma IL-1ß and the number of subcapsular cells in G2-M arrest were reduced after preoperative EPO, but not after remote ischemic preconditioning. These data suggest an intrarenal mechanism acting within cortical cells that may underpin a renoprotective function for preoperative EPO and, to a limited extent, remote ischemic preconditioning. Despite equivocal longer-term outcomes in clinical studies investigating EPO as a renoprotective agent in AKI, optimal clinical dosing and administration have not been established. Our data suggest further clinical studies on the potential renoprotective effect of EPO and remote ischemic preconditioning are justified.

The microRNA maturation regulator Drosha is an independent predictor of outcome in breast cancer patients.

Drosha is a protein that plays a key role in the biogenesis of microRNAs which are well known to be deranged in human breast cancer (BC). The purpose of the current study was to assess the biological and prognostic value of Drosha protein expression in BC. Drosha protein expression was assessed immunohistochemically in two sets of BC: (1) full-face sections of selected BC series with distinct stages of tumour progression (Normal parenchymal cells, ductal carcinoma in situ (DCIS), primary invasive BC and nodal metastases) to evaluate its differential expression, (2) tissue microarray comprising a large and well-characterised series of unselected clinically annotated invasive BC to investigate its correlation with clinicopathological features and patient outcome. A gradual loss of Drosha cytoplasmic expression was observed along tumour progression from DCIS, to invasive and to metastatic cancer cells. In invasive BC, loss of Drosha cytoplasmic expression was associated with BRCA1 and ER expression and with shorter BC specific survival (BCSS), disease free interval (DFI) and distant metastasis free interval (DMFI). This correlation was maintained in ER negative, HER2 negative, triple negative and LN negative cases. Moreover, loss of cytoplasmic Drosha was predictive of better response to chemotherapy and endocrine therapy. This study provides evidence that Drosha protein potentially plays an important role in BC progression and assessment of its expression provides an independent predictor of patient outcome. These observations provide further evidence that alterations in miRNA regulation influence tumour behaviour.

Should a borderline negative HER2 result in a core biopsy of invasive carcinoma of the breast have HER2 assessment repeated in the excision specimen?

AIM: The 2015 UK guidelines for HER2 assessment in breast cancer recommended repeat assessment if the core biopsy was scored as 2+ on HER2 immunohistochemistry (IHC) with borderline negative in situ hybridisation (ratio of number of HER2 to chromosome 17 centromere copies of 1.8-1.99). This case series aimed to assess the value of such repeat assessment in the surgical specimen, in particular the proportion that were HER2 positive. METHODS: Details of biopsies with 2+ IHC and borderline negative in situ hybridisation were extracted from a database. The results of repeat HER2 testing in the surgical specimen for this cohort study were then obtained. RESULTS: 112 patients with no preoperative treatment had repeat assessment: 4 were 3+ and 16 were 2+ amplified. Of 14 with preoperative chemotherapy, 1 was 3+ and 4 were 2+ amplified. All the 2+ amplified carcinomas had a HER2 to chromosome 17 ratio less than 4, in 50% the ratio was between 2.0 and 2.2, and in 50% the HER2 copy number was less than 4. CONCLUSIONS: Repeat assessment yielded 4% 3+ results and 14% 2+ amplified carcinomas but with low level amplification. These results suggest that retesting of borderline negative HER2 cases should be optional and no longer mandatory.

The prognostic significance of lymphovascular invasion in invasive breast carcinoma.

BACKGROUND: Although lymphovascular invasion (LVI) has been associated with a poor outcome in patients with breast cancer, it is not included in most internationally recognized staging systems, including the American Joint Committee on Cancer tumor, lymph node, metastasis (TNM) classification. This is mainly because it remains unclear whether the presence of LVI is an independent, high-risk criterion in clinically relevant staging subgroups. METHODS: The current study was based on a large and well characterized consecutive series of patients who had operable (pathologic T1 [pT1]-pT2, pathologic N0 [pN0]-pN3, M0) breast cancer (3812 informative cases) who were treated according to standard protocols at a single institution and who had long-term follow-up to assess the prognostic value of definite LVI in clinically and molecularly relevant staging subgroups. RESULTS: LVI was strongly associated with both breast cancer-specific survival (BCSS) and distant metastasis-free survival (DMFS) in the entire series and in different subgroups. Multivariate analyses identified LVI as an independent predictor of both BCSS and DMFS in patients with operable breast cancer overall; in the TNM clinical subgroups pT1a-pT1c/pN0 and pT2/pN0; and in the molecular classes estrogen receptor (ER)-positive, ER-negative, human epidermal growth factor 2 [HER2]-negative, and triple-negative. In patients who had lymph node-negative tumors, LVI could be used as a high-risk criterion providing survival disadvantage equivalent to that provided by 1 or 2 involved lymph nodes (pN0 to pN1) and to that provided by 1 size category (pT1 to pT2). The use of immunohistochemistry for detecting an endothelial-specific marker contributed to the prognostic significance of LVI when applied to routine LVI negative/possible cases. CONCLUSIONS: LVI provided a strong predictor of outcome in patients with invasive breast cancer and should be incorporated into breast cancer staging systems.

Loss of Dicer expression is associated with breast cancer progression and recurrence.

Dicer is a protein that plays a pivotal role in the final steps of the microRNA (miRNA) processing pathway, to produce mature miRNAs from their precursor molecules. The purpose of the current study was to assess the biological and prognostic value of Dicer protein expression in breast cancer (BC). Dicer protein expression was assessed immunohistochemically in two sets of BC: (1) full-face sections of selected BC series with distinct stages of tumour progression (normal, in situ (DCIS), primary invasive BC and nodal metastases) to evaluate its differential expression. (2) Tissue microarray comprising a large and well-characterised series of unselected clinically annotated invasive BC (n = 1,174) to investigate its correlation with clinicopathological features and patient outcome. A gradual loss of Dicer protein expression was observed in malignant compared to normal breast tissues, with the loss being the least in DCIS and most prominent in metastatic malignant cells. In invasive BC, loss of Dicer expression was associated with features of aggressive behaviour including higher histological grade, loss of hormone receptor and BRCA1 protein expression and with shorter disease-free survival (DFS). Dicer expression was an independent predictor of recurrence in the aggressive HER2-positive subgroup. Moreover, loss of Dicer was predictive of better response to chemotherapy and to endocrine therapy. This study provides evidence that Dicer protein plays a role in human BC progression and behaviour, and assessment of its expression could provide prognostic information in BC including the HER2-positive class.

Concordance of HER2 status assessed on needle core biopsy and surgical specimens of invasive carcinoma of the breast.

AIMS: Human epidermal growth factor receptor 2 (HER2) status of invasive breast cancers is vital for selection of patients for trastuzumab treatment. This study aimed to assess the level of agreement of HER2 status in core biopsy and excision specimens using immunohistochemistry, with in-situ hybridisation for equivocal cases. METHODS AND RESULTS: 300 consecutive invasive carcinomas with core biopsy and surgical specimens had HER2 assessed on both specimens. Immunohistochemistry was performed first. Fluorescence in-situ hybridization (FISH) was automatically performed if the immunohistochemistry was scored as equivocal (2+). There was agreement between the HER2 status of the two specimens in 294 tumours (98%). In two carcinomas the core was negative and the excision specimen showed focal strong staining with amplification. In four carcinomas the core biopsy was negative and the excision showed 2+ staining with amplification in at least one block (although in three there was no amplification in a second block). CONCLUSION: There is excellent agreement between HER2 assessed in core biopsy and surgical specimens. Discrepancies arise most frequently due to focal amplification or levels of gene amplification around the cut-off for defining positivity.

Expression of the tumour antigen T21 is up-regulated in prostate cancer and is associated with tumour stage.

OBJECTIVES: • To define the expression pattern of the tumour antigen T21 at the protein level in prostate tissues, prostate cell lines and a panel of normal tissues. • To correlate the expression pattern of T21 in prostate cancer with clinical parameters. PATIENTS AND METHODS: • Tissue samples were collected from 79 patients presenting at clinic with either prostate cancer (63 patients) or benign prostatic hyperplasia (BPH, 16 patients). • A tissue microarray (TMA) was constructed from 44 of the prostate cancer tissues and areas of benign disease (43 patients) from these tissues were also included on the TMA. The remaining tissues (prostate cancer 19 patients and BPH 16 patients) were mounted fresh frozen onto cork boards and sectioned. • Full ethical approval was granted for all aspects of the study and informed patient consent was taken before tissue collection. • Immunohistochemistry was used on the prostate tumour TMA, the normal tissue TMA and the fresh-frozen prostate tissues. Fluorescent microscopy and flow cytometry was performed on prostate cell lines. RESULTS: • Expression of T21 was highly restricted within normal tissues with only the stomach, ovary, breast and prostate having detectable T21 expression. • T21 was significantly over-expressed in prostate cancer glands compared with benign tissue and was present in >80% of the malignant specimens analysed. • Increased expression was positively correlated to pathological stage of prostate tumours. • Additionally, T21 was associated with Gleason grade and prostate-specific antigen recurrence, although statistical significance was not reached in this restricted cohort of patients. CONCLUSION: • Taken together these results show that T21 is a potential new biomarker for advanced disease and that elevated levels of T21 appear relevant to prostate cancer development.

Outcome of breast lesions diagnosed as lesion of uncertain malignant potential (B3) or suspicious of malignancy (B4) on needle core biopsy, including detailed review of epithelial atypia.

AIMS: To provide updated evidence of the outcome of breast lesions of uncertain malignant potential (B3) and suspicious of malignancy (B4) diagnosed on needle core biopsy (NCB) and analyse the outcome of the different types of intraductal epithelial atypia. METHODS AND RESULTS: One-hundred and forty-nine B3 and 26 B4 NCBs diagnosed over a 2-year period (2007-2008) were compared with those diagnosed over a previous 2-year period (1998-2000). The proportion of B3 diagnoses increased from 3.1% to 4.5%, and the positive predictive value (PPV) of malignancy of a B3 core decreased from 25% to 10%. Increased diagnosis of radial scar and reductions in the PPV of lobular neoplasia and of atypical intraductal proliferation may explain the reduction in the PPV of the B3 group as a whole. There were no significant changes in the proportion of B4 diagnosis (1.1% and 0.8%) or the PPV of B4 (83% and 88%). Review of cores with intraductal atypia showed a wide range of PPVs, from 100% for suspicious of ductal carcinoma in situ, to 40% for atypical ductal hyperplasia categorized as B3, and 14% for isolated flat epithelial atypia. CONCLUSION: The study has found a decrease in the PPV for a B3 diagnosis and suggests possible explanations.