The clinical significance of oestrogen receptor expression in breast ductal carcinoma in situ.

BACKGROUND: Oestrogen receptor (ER) in invasive breast cancer (BC) predicts response to endocrine therapy (ET) and provides prognostic value. In this study, we investigated the value of ER expression in ductal carcinoma in situ (DCIS) in terms of outcome and the impact on ET decision. METHODS: In total, 643 pure DCIS, diagnosed at Nottingham University Hospitals, were assessed for ER. Clinicopathological data were correlated against ER status, together with assessment of recurrence rate. RESULTS: ER positivity was observed in 74% (475/643) of cases. ER positivity was associated with clinicopathological variables of good prognosis; however, outcome analysis revealed that ER status was not associated with local recurrence. In the intermediate- and high-grade ER-positive DCIS, 58% (11/19) and 63% (15/24) of the recurrences were invasive, respectively, comprising 7% and 6% of all ER-positive DCIS, respectively. Invasive recurrence in low-grade DCIS was infrequent (2%), and none of these patients died of BC. The ER status of the recurrent invasive tumours matched the primary DCIS ER status (94% in ipsilateral and 90% of contralateral recurrence). CONCLUSION: The strong correlation between DCIS and invasive recurrence ER status and the clinical impact of ET justify discussion of the use of ET in ER-positive DCIS treated by breast-conserving surgery. The excellent outcome of low-grade DCIS, which was almost always ER-positive, does not, in the opinion of authors, justify the use of risk-reducing ET. Therefore, the decision on ET for DCIS should be personalised and consider grade, ER status and other characteristics.

Correction: The clinical significance of oestrogen receptor expression in breast ductal carcinoma in situ.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Therapeutic mammaplasty is a safe and effective alternative to mastectomy with or without immediate breast reconstruction.

BACKGROUND: Therapeutic mammaplasty (TM) may be an alternative to mastectomy, but few well designed studies have evaluated the success of this approach or compared the short-term outcomes of TM with mastectomy with or without immediate breast reconstruction (IBR). Data from the national iBRA-2 and TeaM studies were combined to compare the safety and short-term outcomes of TM and mastectomy with or without IBR. METHODS: The subgroup of patients in the TeaM study who underwent TM to avoid mastectomy were identified, and data on demographics, complications, oncology and adjuvant treatment were compared with those of patients undergoing mastectomy with or without IBR in the iBRA-2 study. The primary outcome was the percentage of successful breast-conserving procedures in the TM group. Secondary outcomes included postoperative complications and time to adjuvant therapy. RESULTS: A total of 2916 patients (TM 376; mastectomy 1532; mastectomy and IBR 1008) were included in the analysis. Patients undergoing TM were more likely to be obese and to have undergone bilateral surgery than those having IBR. However, patients undergoing mastectomy with or without IBR were more likely to experience complications than the TM group (TM: 79, 21·0 per cent; mastectomy: 570, 37·2 per cent; mastectomy and IBR: 359, 35·6 per cent; P < 0·001). Breast conservation was possible in 87·0 per cent of patients who had TM, and TM did not delay adjuvant treatment. CONCLUSION: TM may allow high-risk patients who would not be candidates for IBR to avoid mastectomy safely. Further work is needed to explore the comparative patient-reported and cosmetic outcomes of the different approaches, and to establish long-term oncological safety.

ANTECEDENTES: La mamoplastia terapéutica (therapeutic mammaplasty, TM) puede ser una alternativa a la mastectomía, pero hay pocos estudios bien diseñados que hayan evaluado el éxito de esta estrategia o hayan comparado los resultados a corto plazo de la TM con la mastectomía con o sin (+/-) reconstrucción mamaria inmediata (immediate breast reconstruction, IBR). Para comparar la seguridad y los resultados a corto plazo de la TM y la mastectomía +/- IBR se combinaron los datos de los estudios nacionales iBRA-2 y TeaM. MÉTODOS: En el estudio TeaM se identificó el subgrupo de pacientes al que se realizó una TM para evitar la mastectomía y se compararon los datos demográficos, las complicaciones, los resultados oncológicos y el tratamiento adyuvante con las pacientes sometidas a mastectomía +/- IBR del estudio iBRA-2. La variable principal fue el porcentaje de éxito de la cirugía conservadora de mama en el grupo TM. Las variables secundarias fueron las complicaciones postoperatorias y el intervalo de tiempo hasta el inicio del tratamiento adyuvante. RESULTADOS: Se incluyeron en el análisis 2.916 pacientes (TM n = 376; mastectomía n = 1.532; IBR n = 1.008). La TM era más frecuente en pacientes obesas o en las sometidas a cirugía bilateral en comparación con las pacientes con IBR. Sin embargo, las pacientes sometidas a una mastectomía +/- IBR tenían más probabilidades de desarrollar complicaciones que las del grupo TM (TM n = 79, 21,0%; mastectomía n = 570, 37,2%; mastectomía y IBR n = 359, 35,6%; P < 0,001). La conservación de la mama fue posible en el 87% de las pacientes con TM y el procedimiento no retrasó el inicio del tratamiento adyuvante. CONCLUSIÓN: La TM puede permitir que pacientes de alto riesgo que no serían candidatas a IBR eviten la mastectomía de una forma segura. Se necesitan más trabajos para comparar los resultados percibidos por las pacientes y los estéticos de las diferentes estrategias terapéuticas y establecer la seguridad oncológica a largo plazo.

Intra-operative spectroscopic assessment of surgical margins during breast conserving surgery.

BACKGROUND: In over 20% of breast conserving operations, postoperative pathological assessment of the excised tissue reveals positive margins, requiring additional surgery. Current techniques for intra-operative assessment of tumor margins are insufficient in accuracy or resolution to reliably detect small tumors. There is a distinct need for a fast technique to accurately identify tumors smaller than 1 mm2 in large tissue surfaces within 30 min. METHODS: Multi-modal spectral histopathology (MSH), a multimodal imaging technique combining tissue auto-fluorescence and Raman spectroscopy was used to detect microscopic residual tumor at the surface of the excised breast tissue. New algorithms were developed to optimally utilize auto-fluorescence images to guide Raman measurements and achieve the required detection accuracy over large tissue surfaces (up to 4 × 6.5 cm2). Algorithms were trained on 91 breast tissue samples from 65 patients. RESULTS: Independent tests on 121 samples from 107 patients - including 51 fresh, whole excision specimens - detected breast carcinoma on the tissue surface with 95% sensitivity and 82% specificity. One surface of each uncut excision specimen was measured in 12-24 min. The combination of high spatial-resolution auto-fluorescence with specific diagnosis by Raman spectroscopy allows reliable detection even for invasive carcinoma or ductal carcinoma in situ smaller than 1 mm2. CONCLUSIONS: This study provides evidence that this multimodal approach could provide an objective tool for intra-operative assessment of breast conserving surgery margins, reducing the risk for unnecessary second operations.

Current practice and short-term outcomes of therapeutic mammaplasty in the international TeaM multicentre prospective cohort study.

BACKGROUND: Therapeutic mammaplasty, which combines breast reduction and mastopexy techniques with tumour excision, may extend the boundaries of breast-conserving surgery and improve outcomes for patients, but current practice is unknown and high-quality outcome data are lacking. This prospective multicentre cohort study aimed to explore the practice and short-term outcomes of the technique. METHODS: Consecutive patients undergoing therapeutic mammaplasty at participating centres between 1 September 2016 and 30 June 2017 were recruited to the study. Demographic, preoperative, operative, oncological and complication data were collected. The primary outcome was unplanned reoperation for complications within 30 days of surgery. Secondary outcomes included re-excision rates and time to adjuvant therapy. RESULTS: Overall, 880 patients underwent 899 therapeutic mammaplasty procedures at 50 centres. The most common indications were avoidance of poor cosmetic outcomes associated with standard breast-conserving surgery (702 procedures, 78·1 per cent) or avoidance of mastectomy (379, 42·2 per cent). Wise-pattern skin incisions were the most common (429 of 899, 47·7 per cent), but a range of incisions and nipple-areola pedicles were used. Immediate contralateral symmetrization was performed in one-third of cases (284 of 880, 32·3 per cent). In total, 205 patients (23·3 per cent) developed a complication, but only 25 (2·8 per cent) required reoperation. Median postoperative lesion size was 24·5 (i.q.r. 16-38) mm. Incomplete excision was seen in 132 procedures (14·7 per cent), but completion mastectomy was required for only 51 lesions (5·7 per cent). Median time to adjuvant therapy was 54 (i.q.r. 42-66) days. CONCLUSION: Therapeutic mammaplasty is a safe and effective alternative to mastectomy or standard breast-conserving surgery. Further work is required to explore the impact of the technique on quality of life, and to establish cost-effectiveness.

MYC functions are specific in biological subtypes of breast cancer and confers resistance to endocrine therapy in luminal tumours.

BACKGROUND: MYC is amplified in approximately 15% of breast cancers (BCs) and is associated with poor outcome. c-MYC protein is multi-faceted and participates in many aspects of cellular function and is linked with therapeutic response in BCs. We hypothesised that the functional role of c-MYC differs between molecular subtypes of BCs. METHODS: We therefore investigated the correlation between c-MYC protein expression and other proteins involved in different cellular functions together with clinicopathological parameters, patients' outcome and treatments in a large early-stage molecularly characterised series of primary invasive BCs (n=1106) using immunohistochemistry. The METABRIC BC cohort (n=1980) was evaluated for MYC mRNA expression and a systems biology approach utilised to identify genes associated with MYC in the different BC molecular subtypes. RESULTS: High MYC and c-MYC expression was significantly associated with poor prognostic factors, including grade and basal-like BCs. In luminal A tumours, c-MYC was associated with ATM (P=0.005), Cyclin B1 (P=0.002), PIK3CA (P=0.009) and Ki67 (P<0.001). In contrast, in basal-like tumours, c-MYC showed positive association with Cyclin E (P=0.003) and p16 (P=0.042) expression only. c-MYC was an independent predictor of a shorter distant metastases-free survival in luminal A LN+ tumours treated with endocrine therapy (ET; P=0.013). In luminal tumours treated with ET, MYC mRNA expression was associated with BC-specific survival (P=0.001). In ER-positive tumours, MYC was associated with expression of translational genes while in ER-negative tumours it was associated with upregulation of glucose metabolism genes. CONCLUSIONS: c-MYC function is associated with specific molecular subtypes of BCs and its overexpression confers resistance to ET. The diverse mechanisms of c-MYC function in the different molecular classes of BCs warrants further investigation particularly as potential therapeutic targets.

Biological and clinical significance of PARP1 protein expression in breast cancer.

Poly(ADP-ribose) polymerase-1 (PARP1) is a key facilitator of DNA repair. PARP inhibitors have gained recent attention as promising therapeutic agents for the treatment of solid tumours including breast cancer (BC). However, the biological and clinical significance of PARP1 expression in BC and its role in DNA-damage response (DDR) remain to be defined. We investigated the expression of PARP1 expression, cleaved (PARP1c) and non-cleaved (PAR1nc) forms, in a large and well-characterised cohort of clinically annotated stage I-III operable BCs (n = 1,269) and 43 BRCA1-mutated BCs using immunohistochemistry. PARP1 expression was correlated to clinicopathological variables, outcome and expression of other key DNA repair proteins (BRCA1, RAD51, Ku70/80, PIASγ and CHK1). Expression of PARP1 was exclusively nuclear. 49 and 85 % of sporadic BC showed expression PARP1nc and PARP1c, respectively. In BRCA1-mutated tumours, PARP1nc/PARP1c was highly expressed (95 and 79 %, respectively). PARP1nc expression was positively associated with premenopausal younger age patients, larger size and higher tumour grade. PARP1 was positively associated with DDR-proteins; RAD51, BRCA1, CHK1 and PIASγ (p < 0.001). Negative association was found between PARP1nc and Ki67. PARP1c was associated with ER (p < 0.001). Different associations between PARP1 and DDR-proteins were observed when stratified based on ER/BRCA1 status. PARP1 was not an independent predictor of outcome in sporadic or BRCA1-mutated BC. Our results demonstrate a potential biological role for PARP1c and PARP1nc in DNA repair in BC based on the significant association with other key DNA damage repair proteins. These associations were not restricted to ER-negative or triple-negative subgroup.

DNA damage response markers are differentially expressed in BRCA-mutated breast cancers.

Cells have stringent DNA repair pathways that are specific for each different set of DNA lesions which is accomplished through the integration of complex array of proteins. However, BRCA-mutated breast cancer (BC) has defective DNA repair mechanisms. This study aims to investigate differential expression of a large panel of DNA repair markers to characterise DNA repair mechanisms in BRCA-associated tumours compared to sporadic tumours in an attempt to characterise these tumours in routine practice. Immunohistochemistry and tissue microarray technology were applied to a cohort of clinically annotated series of sporadic (n = 1849), BRCA1-mutated (n = 48), and BRCA2-mutated (n = 27) BC. The following DNA damage response (DDR) markers are used; BRCA1, BRCA2, RAD51, Ku70/Ku80, BARD, PARP1 (cleaved), PARP1 (non-cleaved), and P53 in addition to basal cytokeratins, ER, PR, and HER2. A significant proportion of BRCA1 tumours were positive for PARP1 (non-cleaved), and negative for BARD1 and RAD51 compared with sporadic BC. BRCA2 tumours were significantly positive for PARP1 (non-cleaved) compared with sporadic tumours. RAD51 was significantly higher in BRCA1 compared with BRCA2 tumours (p = 0.005). When BRCA1/2 BCs were compared to triple-negative (TN) sporadic tumours of the studied DDR proteins, BARD1 (p < 0.001), PARP1 (non-cleaved) (p < 0.001), and P53 (p = 0.002) remained significantly different in BRCA1/2 tumours compared with TN BC. DNA repair markers showed differential expression in BRCA-mutated tumours, with a substantial degree of disruption of DNA repair pathways in sporadic BC especially TN BC. DNA double-strand break (DSB) repair is assisted by PARP1 expression in BRCA-mutated tumours, whereas the loss of DSB repair via RAD51 is predominant in BRCA1 rather than BRCA2 BC.

Oncoplastic and reconstructive breast surgery in the elderly.

BACKGROUND: The recommendations of the UK All Party Parliamentary Group on Breast Cancer (2013) have been endorsed recently by the UK Association of Breast Surgeons and are in line with the 2007 Cancer Reform Strategy, which states that treatment in older British women should be equivalent to that in younger patients unless precluded by co-morbidity or patient choice. Oncoplastic and reconstructive techniques are increasingly available to women with breast cancer. A review of the literature was carried out to investigate use of these techniques in older patients. METHODS: A MEDLINE search was conducted to identify studies relating to oncoplastic and reconstructive surgery in the elderly. RESULTS AND CONCLUSION: Nine studies were identified and included in the review. Older patients undergoing reconstruction, particularly autologous reconstruction, have outcomes that are at least as good as those achieved in younger patients, yet are far less likely to be offered these techniques. Issues influencing oncoplastic and reconstructive surgery in the elderly include: lack of standard pathways of care, concerns regarding higher operative risk, lack of evidence regarding outcomes, preconceptions regarding body image and lack of engagement with the decision-making process. A minority of older women are likely to accept reconstruction, but those who do are pleased with the results and experience good quality of life. There is now a range of safe oncoplastic and reconstructive options that could be considered as an alternative to standard mastectomy or wide local excision in older patients.

Qualitative mammographic findings and outcomes of surveillance mammography after partial breast reconstruction with an autologous flap.

BACKGROUND: This study describes the qualitative mammographic features after partial breast reconstruction with an autologous flap, and evaluates the diagnostic accuracy and recall rates of surveillance mammography after volume replacement in breast conserving surgery. METHODS: Patients who had autologous partial breast reconstruction (N = 102) after breast-conserving surgery using either the myocutaneous latissimus dorsi mini-flap (N = 39) or fasciocutaneous chest wall perforator flap (N = 63) were reviewed. Mammograms done at one-year post surgery were analysed for characteristic qualitative features. All surveillance mammograms, diagnostic imaging and medical records were retrospectively reviewed. RESULTS: Mammograms of partially reconstructed breasts had distinctive features that correlated well with the surgical procedures. Median follow-up was 3 years, range 0-11 years. Of 295 surveillance mammograms, six (2%) resulted in a recall for further imaging and 3 (1%) proceeded to needle biopsy. Diagnostic imaging was performed for 13 (13/102, 12.7%) patients with symptoms, and only one (1/102, 1%) required a diagnostic biopsy. CONCLUSIONS: A conserved breast with an autologous flap within has characteristic mammographic features that differ from those after standard breast conserving surgery. Surveillance mammography after partial breast reconstruction is accurate, and recall/biopsy rates are low. Diagnostic breast ultrasound examination is effective evaluation for the symptomatic patient.

Prognostic and biological significance of proliferation and HER2 expression in the luminal class of breast cancer.

The definition of Luminal-B subclass of breast cancer (BC) varies in literature. In this study, we have compared the proliferation status; assessed using KI67 labeling index (KI67-LI), and HER2-expression in estrogen receptor positive (ER+) BC to assess their impact on the biological and clinical characteristics of luminal-BC. 1547 (73.8 %) well-characterized clinically annotated stage I-III ER + BC were assessed for expression of KI67, HER2 (ASCO guidelines), and a large panel of relevant biomarkers (no = 37). 46.3 % of the cases show high KI67-LI (>13 %) and 8.4 % show HER2+ and both markers are positively associated with younger age, higher tumor grade and poorer outcome. High KI67-LI and HER2+ are associated with upregulation of ER-coactivators and proliferation-related markers and with downregulation of good prognostic markers. High KI67-LI is associated with larger size, advanced stage, and lymphovascular invasion (LVI) and with downregulation of luminal-enriched and DNA-damage repair markers. In contrast, HER2+ is associated with upregulation of ER-regulated proteins and E-cadherin. When analysis is restricted to high KI67-LI subgroup, HER2+ shows an association with upregulation of differentiation-associated proteins and E-cadherin. Conversely, within HER2+ class, high KI67-LI maintains its association with downregulation of differentiation-associated/luminal-enriched proteins. Outcome analyses indicate that both markers are independently associated with shorter survival but HER2+ is associated with a worse outcome. Although both are associated with high proliferation and poor prognosis within ER + BC, HER2+ is less frequent than high KI67-LI. Unlike KI67, HER2 seems to independently drive the aggressive behavior of ER+ tumors without downregulation of luminal proteins.

Therapeutic mammaplasty.

Therapeutic mammaplasty is a term for the oncoplastic application of breast reduction and mastopexy techniques to treat selected breast tumours by breast conserving surgery (BCS). It has the potential to increase the indications for BCS as well as achieve more acceptable aesthetic results from it in suitable women. Now an established technique in the range of oncoplastic options for women with breast cancer, it finds common application and is associated with good oncological and quality of life outcomes.

Explantation with Lateral Pedicle Mastopexy.

BACKGROUND: While breast explantation combined with mastopexy is an increasingly common procedure, it does present certain technical difficulties. We present a technique of explantation mastopexy with the use of an extended lateral pedicle for auto-augmentation. METHODS: A consecutive series of 40 cases was retrospectively reviewed, with patient reported outcome questionnaire and photography at 3 and 12 months. RESULTS: The mean age was 57 years (range 40 - 70 years), and mean duration of implantation was 20.4 years (range 7 - 42 years). 12 women had undergone previous mastopexy (30%). Minor wound complications requiring simple dressings were seen in 7 cases (17.5%). Major infected wound problems occurred in 1 case, who was a smoker and had other co-morbidities. All except 1 case reported being satisfied or very satisfied with the outcome, with a mean patient reported satisfaction score of 4.9/5. When the photographs were independently assessed by a cosmetic practitioner, all cases were rated as average, good or very good, with a mean score of 4.1/5. CONCLUSIONS: The procedure is associated with low risk of post-operative complications, good cosmetic outcomes, and a high degree of patient satisfaction. We feel this technique provides a logical, reproducible method for combined explantation and mastopexy.

Identification of key clinical phenotypes of breast cancer using a reduced panel of protein biomarkers.

BACKGROUND: Breast cancer is a heterogeneous disease characterised by complex molecular alterations underlying the varied behaviour and response to therapy. However, translation of cancer genetic profiling for use in routine clinical practice remains elusive or prohibitively expensive. As an alternative, immunohistochemical analysis applied to routinely processed tissue samples could be used to identify distinct biological classes of breast cancer. METHODS: In this study, 1073 archival breast tumours previously assessed for 25 key breast cancer biomarkers using immunohistochemistry and classified using clustering algorithms were further refined using naïve Bayes classification performance. Criteria for class membership were defined using the expression of a reduced panel of 10 proteins able to identify key molecular classes. We examined the association between these breast cancer classes with clinicopathological factors and patient outcome. RESULTS: We confirm patient classification similar to established genotypic biological classes of breast cancer in addition to novel sub-divisions of luminal and basal tumours. Correlations between classes and clinicopathological parameters were in line with expectations and showed highly significant association with patient outcome. Furthermore, our novel biological class stratification provides additional prognostic information to the Nottingham Prognostic Index. CONCLUSION: This study confirms that distinct molecular phenotypes of breast cancer can be identified using robust and routinely available techniques and both the luminal and basal breast cancer phenotypes are heterogeneous and contain distinct subgroups.

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.

Pleomorphic lobular carcinoma of the breast: is it a prognostically significant pathological subtype independent of histological grade?

Pleomorphic lobular carcinoma is regarded as a biologically aggressive variant of invasive lobular carcinoma of the breast. However, there is no consensus on the definition and whether this subtype adds useful information to histological grade. Two-hundred and two grade 2 or grade 3 invasive lobular carcinomas were studied. Tumours were categorised according to the components of histological grade: tubules, pleomorphism and mitoses. Pleomorphic lobular carcinoma was defined as a carcinoma with a lobular growth pattern and marked nuclear pleomorphism (pleomorphism 3). Breast cancer-specific survival was used in analysis of prognosis. Grade 3 pleomorphic lobular carcinomas (tubules 3, pleomorphism 3, mitoses 2 and tubules 3, pleomorphism 3, mitoses 3) had a worse prognosis than grade 2 (tubules 3, pleomorphism 2, mitoses 1) carcinomas. Grade 2 lobular carcinomas with marked nuclear pleomorphism (tubules 3, pleomorphism 3, mitoses 1) had a similar prognosis to grade 2 carcinomas with moderate pleomorphism (tubules 3, pleomorphism 2, mitoses 1). Survival was associated with mitotic score, but not with nuclear pleomorphism on both univariate and multivariate analysis. A non-classical growth pattern was seen more frequently in all subgroups with marked nuclear pleomorphism and was associated with worse survival. Histological grade and nodal status were independent of prognostic factors. This study shows that histological grade (in particular the mitotic component) in invasive lobular carcinomas is of prognostic importance, but pleomorphic type does not provide useful additional prognostic information.

Calpain system protein expression in basal-like and triple-negative invasive breast cancer.

BACKGROUND: Basal-like and triple-negative breast tumours encompass an important clinical subgroup and biomarkers that can prognostically stratify these patients are required. MATERIALS AND METHODS: We investigated two breast cancer tissue microarrays for the expression of calpain-1, calpain-2 and calpastatin using immunohistochemistry. The first microarray was comprised of invasive tumours from 1371 unselected patients, and the verification microarray was comprised of invasive tumours from 387 oestrogen receptor (ER)-negative patients. RESULTS: The calpain system contains a number of proteases and an endogenous inhibitor, calpastatin. Calpain activity is implicated in important cellular processes including cytoskeletal remodelling, apoptosis and survival. Our results show that the expression of calpastatin and calpain-1 are significantly associated with various clinicopathological criteria including tumour grade and ER expression. High expression of calpain-2 in basal-like or triple-negative disease was associated with adverse breast cancer-specific survival (P = 0.003 and <0.001, respectively) and was verified in an independent cohort of patients. Interestingly, those patients with basal-like or triple-negative disease with a low level of calpain-2 expression had similar breast cancer-specific survival to non-basal- or receptor- (oestrogen, progesterone or human epidermal growth factor receptor 2 (HER2)) positive disease. CONCLUSIONS: Expression of the large catalytic subunit of m-calpain (calpain-2) is significantly associated with clinical outcome of patients with triple-negative and basal-like disease.