Markers associated with genomic instability, immunogenicity and immune therapy responsiveness in Metaplastic carcinoma of the breast: Expression of γH2AX, pRPA2, P53, PD-L1 and tumor infiltrating lymphocytes in 76 cases.

BACKGROUND: Metaplastic breast cancer (MpBC) is an aggressive subtype of breast carcinoma that is often resistant to conventional chemotherapy. Therefore, novel treatment strategies are urgently needed. Immune check point inhibitors have shown activity in programmed death-ligand 1 (PD-L1) - positive metastatic triple negative breast carcinoma (TNBC), which raises the possibility that immunotherapy may also be effective in MpBC as most of the MpBCs are triple negative. The aim of the present study was to assess genomic instability and immunogenicity in tumor specimens of patients with MpBC. METHODS: A total of 76 patients diagnosed with MpBC over a 15-year period were included in the study. We performed immunohistochemical analyses for tumor cell PD-L1, immune cell PD-L1 and p53 on tissue microarrays (TMAs), analyzed stromal and intratumoral tumor infiltrating lymphocytes (TILs) from hematoxylin and eosin-stained (H&E) slides and scored gamma-H2AX (γH2AX) and phosphorylated-RPA2 (pRPA2) from whole tissue sections. We correlated marker expression with clinicopathologic features and clinical outcome. RESULTS: All tumors expressed γH2AX and pRPA2 with median expressions of 43% and 44%. P53- (68%), tumor cell PD-L1- (59%) and immune cell PD-L1-positivity (62%) were common in MpBCs. Median stromal TIL and intratumoral TIL counts were 5% and 0. The spindle and squamous cell carcinomas expressed the highest levels of PD-L1 and TILs, and carcinoma with mesenchymal differentiation the lowest. CONCLUSIONS: MpBC appears to be an immunogenic cancer with high genomic instability and frequent PD-L1-positivity, implying that check point inhibitors might be effective in MpBC. Expression levels of PD-L1 and TILs varied across different histologic subtypes, suggesting that immunotherapy might be less effective in carcinoma with mesenchymal differentiation.

Axillary nodal metastatic burden in patients with breast cancer with clinically positive axillary nodes.

BACKGROUND: The aim of this study was to determine preoperative factors and tumour characteristics related to a high nodal tumour burden in patients with clinically node-positive breast cancer. These findings were used to construct a predictive tool to evaluate the patient-specific risk of having more than two axillary lymph node metastases. METHODS: Altogether, 507 consecutive patients with breast cancer and axillary lymph node metastasis diagnosed by preoperative ultrasound-guided needle biopsy were reviewed. These patients underwent breast surgery and axillary lymph node dissection at Helsinki University Hospital between 2010 and 2014. Patients were grouped into those with one or two, and those with more than two lymph node metastases. RESULTS: There were 153 patients (30·2 per cent) with one or two lymph node metastases and 354 (69·8 per cent) with more than two metastases. Five-year disease-free survival was poorer for the latter group (P = 0·032). Five-year overall survival estimates for patients with one or two and those with more than two lymph node metastases were 87·0 and 81·4 per cent respectively (P = 0·215). In multivariable analysis, factors significantly associated with more than two lymph node metastases were: age, tumour size, lymphovascular invasion in the primary tumour, extracapsular extension of metastasis in lymph nodes, and morphology of lymph nodes. These factors were included in a multivariable predictive model, which had an area under the curve of 0·828 (95 per cent c.i. 0·787 to 0·869). CONCLUSION: The present study provides a patient-specific prediction model for evaluating nodal tumour burden in patients with clinically node-positive breast cancer.

Deregulated hepsin protease activity confers oncogenicity by concomitantly augmenting HGF/MET signalling and disrupting epithelial cohesion.

Hepsin belongs to a family of cell-surface serine proteases, which have sparked interest as therapeutic targets because of the accessibility of extracellular protease domain for inhibitors. Hepsin is frequently amplified and/or overexpressed in epithelial cancers, but it is not clear how enhanced hepsin expression confers a potential for oncogenicity. We show that hepsin is consistently overexpressed in more than 40% of examined breast cancers, including all major biological subtypes. The effects of doxycycline-induced hepsin overexpression were examined in mammary epithelial organoids, and we found that induced hepsin acutely downmodulates its cognate inhibitor, hepatocyte growth factor (HGF) activator inhibitor type 1 (HAI-1). Hepsin-induced depletion of cellular HAI-1 led to a sharp increase in pericellular serine protease activity. The derepressed hepsin proteolytically activated downstream serine proteases, augmented HGF/MET signalling and caused deterioration of desmosomes and hemidesmosomes; structures important for cell cohesion and cell-basement membrane interaction. Moreover, chronic induction of hepsin considerably shortened the latency of Myc-dependent tumourigenesis in the mouse mammary gland. The serine protease and uPA system inhibitor WX-UK1, identified as a micromolar range hepsin inhibitor, prevented hepsin from augmenting HGF/MET signalling and disrupting desmosomes and hemidesmosomes. The findings suggest that the oncogenic activity of hepsin arises not only from elevated expression level but also from depletion of HAI-1, events which together trigger gain-of-function activity impacting HGF/MET signalling and epithelial cohesion. Thus, hepsin overexpression is a major oncogenic conferrer to a serine protease activity involved in breast cancer dissemination.

Breast cancer prognosis and isolated tumor cell findings in axillary lymph nodes after core needle biopsy and fine needle aspiration cytology: Biopsy method and breast cancer outcome.

BACKGROUND: It is unknown whether performing a core needle biopsy (CNB) to diagnose breast cancer increases the incidence of isolated tumor cells (ITC) in the axillary sentinel lymph nodes. METHODS: Patients diagnosed with unilateral invasive pT1 breast cancer (≤2 cm in diameter, n = 1525) at a single center between February 2001 and August 2005 were included in this prospective observational cohort study. The patients were categorized into two groups according to the type of the preoperative breast needle biopsy performed, the CNB and the fine needle aspiration cytology (FNAC) groups, and followed up for a median of 9.5 years after breast surgery. RESULTS: 868 (56.9%) patients had FNAC and 657 (43.2%) CNB. In the subset of patients with no axillary metastases (pN0, n = 1005) 70 patients had ITC, 37 (4.3%) out of the 546 patients in FNAC group and 33 (5.0%) out of the 459 patients in the CNB group (p = 0.798). The type of tumor biopsy did not influence breast cancer-specific survival (p = 0.461) or local recurrence-free survival (p = 0.814) in univariable survival analyses. Overall, survival favored the CNB group in a univariable analysis, but no difference in survival emerged in a multivariable analysis (p = 0.718). CONCLUSIONS: CNB was not associated with a greater incidence of ITC in axillary lymph nodes as compared with FNAC, and did not have an adverse effect on survival outcomes in a patient population treated with modern adjuvant therapies.

Indication-based national diagnostic reference levels for paediatric CT: a new approach with proposed values.

Indication-based national diagnostic reference levels (DRLs) for a few most common paediatric computed tomography (CT) examinations are proposed. Patient dose data (CTDI vol and dose length product) were collected for over 1000 patients in 4 university hospitals with best experiences in paediatric CT. Four indications for chest CT and two for abdomen (abdomen + pelvis), chest + abdomen and head CT were considered. The DRLs for the body examinations are proposed as exponential DRL-curves, where CTDI vol and dose length product are presented as a function of patient weight. The same DRL curve applies to all the indications studied. The basic 75 % level curve is supplemented by 50 % level curve to enable considerations on varying levels of technology. For head CT, DRLs are proposed for a few age groups (1, 1-5, 5-10 and 10-15 y), separately for routine CT and CT for ventricular size. The proposed DRLs are generally lower than the few published DRLs in other countries.

A predictive tool to estimate the risk of axillary metastases in breast cancer patients with negative axillary ultrasound.

BACKGROUND: Sentinel node biopsy (SNB) is the "gold standard" in axillary staging in clinically node-negative breast cancer patients. However, axillary treatment is undergoing a paradigm shift and studies are being conducted on whether SNB may be omitted in low-risk patients. The purpose of this study was to evaluate the risk factors for axillary metastases in breast cancer patients with negative preoperative axillary ultrasound. METHODS: A total of 1,395 consecutive patients with invasive breast cancer and SNB formed the original patient series. A univariate analysis was conducted to assess risk factors for axillary metastases. Binary logistic regression analysis was conducted to form a predictive model based on the risk factors. The predictive model was first validated internally in a patient series of 566 further patients and then externally in a patient series of 2,463 patients from four other centers. All statistical tests were two-sided. RESULTS: A total of 426 of the 1,395 (30.5 %) patients in the original patient series had axillary lymph node metastases. Histological size (P < 0.001), multifocality (P < 0.001), lymphovascular invasion (P < 0.001), and palpability of the primary tumor (P < 0.001) were included in the predictive model. Internal validation of the model produced an area under the receiver operating characteristics curve (AUC) of 0.731 and external validation an AUC of 0.79. CONCLUSIONS: We present a predictive model to assess the patient-specific probability of axillary lymph node metastases in patients with clinically node-negative breast cancer. The model performs well in internal and external validation. The model needs to be validated in each center before application to clinical use.

Overabundant FANCD2, alone and combined with NQO1, is a sensitive marker of adverse prognosis in breast cancer.

BACKGROUND: Defective DNA repair is central to the progression and treatment of breast cancer. Immunohistochemically detected DNA repair markers may be good candidates for novel prognostic and predictive factors that could guide the selection of individualized treatment strategies. PATIENTS AND METHODS: We have analyzed nuclear immunohistochemical staining of BRCA1, FANCD2, RAD51, XPF, and PAR in relation to clinicopathological and survival data among 1240 paraffin-embedded breast tumors, and additional gene expression microarray data from 76 tumors. The antioxidant enzyme NQO1 was analyzed as a potential modifier of prognostic DNA repair markers. RESULTS: RAD51 [hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.70-0.94, P = 0.0050] and FANCD2 expression (HR 1.50, 95% CI 1.28-1.76, P = 1.50 × 10(-7)) were associated with breast cancer survival. High FANCD2 expression correlated with markers of adverse prognosis but remained independently prognostic in multivariate analysis (HR 1.27, 95% CI 1.08-1.49, P = 0.0043). The FANCD2-associated survival effect was most pronounced in hormone receptor positive, HER2-negative tumors, and in tumors with above-median NQO1 expression. In the NQO1-high subset, patients belonging to the highest quartile of FANCD2 immunohistochemical scores had a threefold increased risk of metastasis or death (HR 3.10, 95% CI 1.96-4.92). Global gene expression analysis indicated that FANCD protein overabundance is associated with the upregulation of proliferation-related genes and a downregulated nucleotide excision repair pathway. CONCLUSION: FANCD2 immunohistochemistry is a sensitive, independent prognostic factor in breast cancer, particularly when standard markers indicate relatively favorable prognosis. Taken together, our results suggest that the prognostic effect is linked to proliferation, DNA damage, and oxidative stress; simultaneous detection of FANCD2 and NQO1 provides additional prognostic value.

International multicenter tool to predict the risk of four or more tumor-positive axillary lymph nodes in breast cancer patients with sentinel node macrometastases.

Recently, many centers have omitted routine axillary lymph node dissection (ALND) after metastatic sentinel node biopsy in breast cancer due to a growing body of literature. However, existing guidelines of adjuvant treatment planning are strongly based on axillary nodal stage. In this study, we aim to develop a novel international multicenter predictive tool to estimate a patient-specific risk of having four or more tumor-positive axillary lymph nodes (ALN) in patients with macrometastatic sentinel node(s) (SN). A series of 675 patients with macrometastatic SN and completion ALND from five European centers were analyzed by logistic regression analysis. A multivariate predictive model was created and validated internally by 367 additional patients and then externally by 760 additional patients from eight different centers. All statistical tests were two-sided. Prevalence of four or more tumor-positive ALN in each center's series (P = 0.010), number of metastatic SNs (P < 0.0001), number of negative SNs (P = 0.003), histological size of the primary tumor (P = 0.020), and extra-capsular extension of SN metastasis (P < 0.0001) were included in the predictive model. The model's area under the receiver operating characteristics curve was 0.766 in the internal validation and 0.774 in external validation. Our novel international multicenter-based predictive tool reliably estimates the risk of four or more axillary metastases after identifying macrometastatic SN(s) in breast cancer. Our tool performs well in internal and external validation, but needs to be further validated in each center before application to clinical use.

Outcome of patients with ductal carcinoma in situ and sentinel node biopsy.

BACKGROUND: In sentinel node biopsy (SNB), tumor-positive findings, mainly micrometastases and isolated tumor cells (ITC) have been found in up to 8%-16% of patients with pure ductal carcinoma in situ (DCIS) or microinvasive DCIS (DCISM). The prognostic significance of such findings is largely unknown. The aim of this study is to examine the outcome of DCIS and DCISM patients with SNB. METHODS: A total of 280 breast cancer patients with pure or microinvasive DCIS underwent SNB between April 2001 and December 2010 at the Breast Surgery Unit of Helsinki University Central Hospital. Patient, tumor, SNB procedure, and follow-up data were gathered. The median follow-up was 50 months (range 7-123 months). RESULTS: Altogether, 21 patients had tumor-positive sentinel node findings. Of these, 14 were in pure DCIS patients (1 macrometastasis, 1 micrometastasis, 12 ITC) and 7 in DCISM patients (1 macrometastasis, 2 micrometastases, 4 ITC). Also, 16 patients, 10 with pure DCIS and 6 with DCISM, underwent completion axillary lymph node dissection (ALND). Only 1 of them, a patient with DCISM, had additional tumor positive finding in the ALND. During a median follow-up of 50 months (range 7-123 months) there were 5 local recurrences. One patient with pure DCIS and tumor-negative SNB developed overt axillary metastases and later also distant metastases. CONCLUSIONS: DCIS and DCISM patients do have tumor positive findings, but a majority of these are ITC or micrometastases. In light of this study, these findings do not affect the outcome of DCIS or DCISM patients.

A simple nomogram to evaluate the risk of nonsentinel node metastases in breast cancer patients with minimal sentinel node involvement.

BACKGROUND: Tumor-positive sentinel node biopsy (SNB) suggests a risk of nonsentinel node metastases in breast cancer. This risk is lower after micrometastasis or isolated tumor cells (ITC) in the sentinel node (SN), and recent studies suggest that completion axillary lymph node dissection (ALND) might not improve outcome in these patients. We aim to validate existing predictive models and to develop a new model for micrometastatic and ITC patients. METHODS: A series of 484 patients with micrometastases or ITC in SN followed by ALND was used to evaluate factors affecting nonsentinel node involvement. Logistic regression analysis was performed to construct a predictive model, which was validated by a separate series of 51 patients. RESULTS: Only 7.2% of patients had additional metastases on completion ALND. Tumor diameter and multifocality associated with nonsentinel status on multivariate analysis. A predictive model was constructed showing good [area under the curve (AUC) 0.791] discrimination in the validation series. Previously published models performed poorly in our patient population. CONCLUSIONS: Nonsentinel node metastases are rare with micrometastasis or ITC in SN. Most published predictive models for nonsentinel node involvement perform poorly in the present patient population. We developed a new predictive model which seems to perform well in discriminating patients with more than 10% risk of additional metastases. However, the presented nomogram needs to be validated with an independent patient series to evaluate its accuracy, especially for high-risk patients.

Multicentre validation of different predictive tools of non-sentinel lymph node involvement in breast cancer.

Sentinel lymph node (SN) biopsy offers the possibility of selective axillary treatment for breast cancer patients, but there are only limited means for the selective treatment of SN-positive patients. Eight predictive models assessing the risk of non-SN involvement in patients with SN metastasis were tested in a multi-institutional setting. Data of 200 consecutive patients with metastatic SNs and axillary lymph node dissection from each of the 5 participating centres were entered into the selected non-SN metastasis predictive tools. There were significant differences between centres in the distribution of most parameters used in the predictive models, including tumour size, type, grade, oestrogen receptor positivity, rate of lymphovascular invasion, proportion of micrometastatic cases and the presence of extracapsular extension of SN metastasis. There were also significant differences in the proportion of cases classified as having low risk of non-SN metastasis. Despite these differences, there were practically no such differences in the sensitivities, specificities and false reassurance rates of the predictive tools. Each predictive tool used in clinical practice for patient and physician decision on further axillary treatment of SN-positive patients may require individual institutional validation; such validation may reveal different predictive tools to be the best in different institutions.

Patient doses in paediatric CT: feasibility of setting diagnostic reference levels.

Despite the fact that doses to paediatric patients from computed tomography (CT) examinations are of special concern, only few data or studies for setting of paediatric diagnostic reference levels (DRLs) have been published. In this study, doses to children were estimated from chest and head CT, in order to study the feasibility of DRLs for these examinations. It is shown that for the DRLs, patient dose data from different CT scanners should be collected in age or weight groups, possibly for different indications. For practical reasons, the DRLs for paediatric chest CT should be given as a continuous DRL curve as a function of patient weight. For paediatric head CT, DRLs for a few age groups could be given. The users of the DRLs should be aware of the calibration phantom applied in the console calibration for different paediatric scanning protocols. The feasibility of DRLs should be re-evaluated every 2-3 y.

Ipsilateral breast recurrence after breast conserving surgery in patients with small (≤ 2cm) breast cancer treated with modern adjuvant therapies.

BACKGROUND: Modern multimodality treatment greatly influences the rate and the predictive factors for ipsilateral cancer recurrence (IBR) after breast conserving surgery. MATERIAL AND METHODS: The study is based on 1297 patients with pT1 breast cancer and treated with breast conserving surgery in February 2001-August 2005. The median duration of follow-up was 57 months. RESULTS: IBR occurred in 27 (2.1%) patients. It was located in the quadrant of prior breast resection in 17 (63%) cases. The median time to an IBR was 41 months (range, 6-78) regardless of whether the recurrence was located in the same or in another quadrant. Omission of radiotherapy was associated with a higher IBR incidence, HR 10,344 (95% CI 1904-56,184; p=0.007). The IBRs occurred particularly often, in 27% of the 11 patients who refused radiotherapy. Patients diagnosed with ER+ cancer had a lower risk of IBR when compared with those with ER-/HER2+ cancer, HR 0.215 (95% CI 0.049-0.935; p=0.040). CONCLUSIONS: The risk of IBR was low during the first 5 years after breast resection among patients with pT1 breast cancer and treated with modern surgical and adjuvant therapies. The majority IBRs still occur at or close to the prior resection site underlining the importance of local therapies. Omission of radiotherapy was the most significant risk factor for IBR.

Mammary-derived growth inhibitor (MDGI) interacts with integrin α-subunits and suppresses integrin activity and invasion.

The majority of mortality associated with cancer is due to formation of metastases from the primary tumor. Adhesion mediated by different integrin heterodimers has an important role during cell migration and invasion. Protein interactions with the ß1-integrin cytoplasmic tail are known to influence integrin affinity for extracellular ligands, but regulating binding partners for the α-subunit cytoplasmic tails have remained elusive. In this study, we show that mammary-derived growth inhibitor (MDGI) (also known as FABP-3 or H-FABP) binds directly to the cytoplasmic tail of integrin α-subunits and its expression inhibits integrin activity. In breast cancer cell lines, MDGI expression correlates with suppression of the active conformation of integrins. This results in reduced integrin adhesion to type I collagen and fibronectin and inhibition of cell migration and invasion. In tissue microarray of 1331 breast cancer patients, patients with MDGI-positive tumors had more favorable 10-year distant disease-free survival compared with patients with MDGI-negative tumors. Our data indicate that MDGI is a novel interacting partner for integrin α-subunits, and its expression modulates integrin activity and suppresses cell invasion in breast cancer patients. Retained MDGI expression is associated with favorable prognosis.

Potential CYP2C9-mediated drug-drug interactions in hospitalized type 2 diabetes mellitus patients treated with the sulphonylureas glibenclamide, glimepiride or glipizide.

OBJECTIVES: Sulphonylureas are widely used in the treatment of type 2 diabetes mellitus (T2DM). Based on laboratory findings, we determined the clinical significance of potential CYP2C9-mediated drug-drug interactions in hospitalized patients receiving glibenclamide, glimepiride or glipizide, all of which are metabolized by CYP2C9, together with a CYP2C9 inhibitor. DESIGN, SETTING AND SUBJECTS: An observational pharmaco-epidemiological database study was performed in a university hospital setting with 3884 patients with T2DM. MAIN OUTCOME MEASURES: Efficacy and safety of sulphonylurea therapy during the potential interaction (sulphonylurea treatment with a CYP2C9 inhibitor) vs. control periods (sulphonylurea treatment without a CYP2C9 inhibitor) were estimated using laboratory parameters. RESULTS: Almost 20% of patients were exposed to a potential drug-drug interaction with a CYP2C9 inhibitor during sulphonylurea treatment. More than 75% of the potential interactions occurred with trimethoprim, metronidazole and fluconazole. When all sulphonylureas were pooled and adjusted for age, gender, ward and sulphonylurea dose, mean and maximum fasting plasma glucose concentrations as well as maximum values of glycosylated haemoglobin were significantly lower during the interaction periods compared with control periods, whereas mean and minimum activities of alanine amino transferase and gamma-glutamyl transferase were higher. The minimum fasting plasma glucose values were more often below the target range in patients with potential interactions. The sulphonylurea dose did not differ significantly between patients who were or were not concomitantly treated with a potentially interacting drug. CONCLUSIONS: Concomitant use of a CYP2C9 inhibitor results in exaggerated pharmacodynamic effects of sulphonylureas and increases the risk of hypoglycaemia in T2DM patients receiving glibenclamide, glimepiride or glipizide.

High frequency of SNAIL-expressing cells confirms and predicts metastatic potential of phaeochromocytoma.

Phaeochromocytomas are uncommon tumours of adrenal or extra-adrenal chromaffin tissue. About 2-26% of these have been reported to metastasize, but, on histological criteria, it is virtually impossible to predict malignant behaviour of the tumour. Using immunohistochemistry, we analysed the protein expression of SNAIL, a zinc-finger transcription factor, in a series of 50 phaeochromocytoma specimens from 42 patients. We found that SNAIL-expressing cells are frequent in metastatic primary tumours and their metastases, whereas in tumours without metastases, SNAIL expression is commonly absent. We conclude that the expression of SNAIL may be of use in predicting the metastatic potential of phaeochromocytoma.

High cyclin B1 expression is associated with poor survival in breast cancer.

Cyclin B1 regulates the G(2)-M transition of the cell cycle. Cyclin B1 expression is higher in premalignant and malignant than normal breast lesions. Correlation of cyclin B1 expression with other histopathological variables and prognostic role in breast cancer are not fully understood. Traditionally used prognostic criteria identify large subset of patients to receive adjuvant chemotherapy and to be exposed to adverse effects. A reliable and simple method helping prognostic evaluation in breast cancer is needed. We analysed cyclin B1 expression on 1348 invasive breast cancers and studied correlations with other histopathological variables and survival. High cyclin B1 correlated with high tumour grade, large tumour size and positive nodal status, oestrogen and progesterone receptor negativity, positive HER2 and p53 status, young age at diagnosis, and high cyclin E, cyclin A and Ki67 expression. Among patients not given adjuvant chemotherapy high cyclin B1 was a strong predictor of shorter overall and metastasis-free survival (RR 3.74, P<0.0005 and RR 3.51, P<0.0005, respectively), and remained as an independent prognostic factor also in multivariate analysis (RR 1.80, P=0.04 and RR 2.31, P=0.02, respectively). This study suggests high cyclin B1 associates with aggressive phenotype and is an independent prognostic factor in breast cancer.

WNT-4 mRNA expression in human adrenocortical tumors and cultured adrenal cells.

The members of the Wnt glycoprotein family are important in embryogenesis and adult tissue homeostasis, and deletion of WNT-4 gene in mice leads to improper development of many organs including the adrenals. The objective of this study was to investigate the expression of WNT-4 gene in human adrenals and adrenocortical tumors. The WNT-4 mRNA expression (analyzed by quantitative real-time RT-PCR) was significantly higher in Conn's adenomas (p<0.01) and lower in Cushing's adenomas, virilizing carcinomas and fetal adrenals (p<0.05) compared with normal adult adrenals. WNT-4 mRNA expression was clearly upregulated by ACTH and 8-bromo-cAMP (8-BrcAMP) in primary cultures of normal adult adrenocortical cells, but downregulated by 8-BrcAMP and 12- O-tetradecanoylphorbol-13-acetate (TPA) in human NCI-H295R adrenocortical carcinoma cells. Angiotensin II tended to increase WNT-4 mRNA expression at 24 hours and decreased it at 48 hours time point in both cell culture types. The abundant WNT-4 mRNA expression in Conn's adenomas and its hormonal regulation in adrenocortical cells suggest a role for WNT-4 in human adrenocortical function.

The prevalence of and risk factors for four or more metastatic axillary lymph nodes in breast cancer patients undergoing sentinel node biopsy.

BACKGROUND: Our aim was to investigate the prevalence of and risk factors for having four or more positive axillary lymph nodes among breast cancer patients undergoing sentinel node (SN) biopsy. PATIENTS AND METHODS: Between February 2005 and July 2007, 1,062 breast cancer patients with the clinical tumour size not larger than 3 cm underwent SN biopsy and axillary clearance (AC), when SN was positive. These patients were identified in a prospectively collected database. RESULTS: Four or more positive axillary nodes were detected in 68 patients representing 6% of the entire study population and 16% of the 436 node positive cases. Features regarded as predictive for a very low risk included (1) T1a or T1b tumours, (2) grade I tumours, (3) tumours with a favourable subtype, that is mucinous, tubular or medullary breast cancer, (4) no nodal macrometastases and (5) SN ratio lower than 0.5. CONCLUSIONS: Only few patients with T1a-b tumours or grade 1 tumours, as well as those with minimal involvement of the sentinel nodes have four or more positive axillary lymph nodes. However, these risk factors can be definitely assessed only after surgery, decreasing their value in the clinical decision making.

The DNA damage signalling kinase ATM is aberrantly reduced or lost in BRCA1/BRCA2-deficient and ER/PR/ERBB2-triple-negative breast cancer.

The ataxia-telangiectasia-mutated (ATM) kinase is a key transducer of DNA damage signals within the genome maintenance machinery and a tumour suppressor whose germline mutations predispose to familial breast cancer. ATM signalling is constitutively activated in early stages of diverse types of human malignancies and cell culture models in response to oncogene-induced DNA damage providing a barrier against tumour progression. As BRCA1 and BRCA2 are also components of the genome maintenance network and their mutations predispose to breast cancer, we have examined the ATM expression in human breast carcinomas of BRCA1/2 mutation carriers, sporadic cases and familial non-BRCA1/2 patients. Our results show that ATM protein expression is aberrantly reduced more frequently among BRCA1 (33%; P=0.0003) and BRCA2 (30%; P=0.0009) tumours than in non-BRCA1/2 tumours (10.7%). Furthermore, the non-BRCA1/2 tumours with reduced ATM expression were more often estrogen receptor (ER) negative (P=0.0002), progesterone receptor (PR) negative (P=0.004) and were of higher grade (P=0.0004). In our series of 1013 non-BRCA1/2 cases, ATM was more commonly deficient (20%; P=0.0006) and p53 was overabundant (47%; P<0.0000000001) among the difficult-to-treat ER/PR/ERBB2-triple-negative subset of tumours compared with cases that expressed at least one of these receptors (10 and 16% of aberrant ATM and p53, respectively). We propose a model of 'conditional haploinsufficiency' for BRCA1/2 under conditions of enhanced DNA damage in precancerous lesions resulting in more robust activation and hence increased selection for inactivation or loss of ATM in tumours of BRCA1/2 mutation carriers, with implications for genomic instability and curability of diverse subsets of human breast cancer.