K Ryder

BRCA1 dysfunction in sporadic basal-like breast cancer.

Basal-like breast cancers form a distinct subtype of breast cancer characterized by the expression of markers expressed in normal basal/myoepithelial cells. Breast cancers arising in carriers of germline BRCA1 mutations are predominately of basal-like type, suggesting that BRCA1 dysfunction may play a role in the pathogenesis of sporadic basal-like cancers. We analysed 37 sporadic breast cancers expressing the basal marker cytokeratin 5/6, and age- and grade-matched controls, for downregulation of BRCA1. Although BRCA1 promoter methylation was no more common in basal-like cancers (basal 14% vs controls 11%, P=0.72), BRCA1 messenger RNA expression was twofold lower in basal-like breast cancers compared to matched controls (P=0.008). ID4, a negative regulator of BRCA1, was expressed at 9.1-fold higher levels in basal-like breast cancer (P<0.0001), suggesting a potential mechanism of BRCA1 downregulation. BRCA1 downregulation correlated with the presence of multiple basal markers, revealing heterogeneity in the basal-like phenotype. Finally, we found that 63% of metaplastic breast cancers, a rare type of basal-like cancers, had BRCA1 methylation, in comparison to 12% of controls (P<0.0001). The high prevalence of BRCA1 dysfunction identified in this study could be exploited in the development of novel approaches to targeted treatment of basal-like breast cancer.

Predicting prognosis using molecular profiling in estrogen receptor-positive breast cancer treated with tamoxifen

BackgroundEstrogen receptor positive (ER+) breast cancers (BC) are heterogeneous with regard to their clinical behavior and response to therapies. The ER is currently the best predictor of response to the anti-estrogen agent tamoxifen, yet up to 30–40% of ER+BC will relapse despite tamoxifen treatment. New prognostic biomarkers and further biological understanding of tamoxifen resistance are required. We used gene expression profiling to develop an outcome-based predictor using a training set of 255 ER+ BC samples from women treated with adjuvant tamoxifen monotherapy. We used clusters of highly correlated genes to develop our predictor to facilitate both signature stability and biological interpretation. Independent validation was performed using 362 tamoxifen-treated ER+ BC samples obtained from multiple institutions and treated with tamoxifen only in the adjuvant and metastatic settings.ResultsWe developed a gene classifier consisting of 181 genes belonging to 13 biological clusters. In the independent set of adjuvantly-treated samples, it was able to define two distinct prognostic groups (HR 2.01 95%CI: 1.29–3.13; p = 0.002). Six of the 13 gene clusters represented pathways involved in cell cycle and proliferation. In 112 metastatic breast cancer patients treated with tamoxifen, one of the classifier components suggesting a cellular inflammatory mechanism was significantly predictive of response.ConclusionWe have developed a gene classifier that can predict clinical outcome in tamoxifen-treated ER+ BC patients. Whilst our study emphasizes the important role of proliferation genes in prognosis, our approach proposes other genes and pathways that may elucidate further mechanisms that influence clinical outcome and prediction of response to tamoxifen.

Occult axillary lymph node metastases are of no prognostic significance in breast cancer

The significance of occult metastases in axillary lymph nodes in patients with carcinoma of the breast is controversial. Additional sections were cut from the axillary lymph nodes of 477 women with invasive carcinoma of the breast, in whom no metastases were seen on initial assessment of haematoxylin and eosin stained sections of the nodes. One section was stained with haematoxylin and eosin, and one using immunohistochemistry with two anti-epithelial antibodies (CAM5.2 and HMFG2). Occult metastases were found in 60 patients (13%). The median follow-up was 18.9 years with 153 breast cancer related deaths. There was no difference in survival between those with and those without occult metastases. Multivariate analysis, however, showed that survival was related to tumour size and histological grade. This node-negative group was compared with a second group of 202 patients who had one involved axillary node found on initial assessment of the haematoxylin and eosin sections; survival was worse in the patients in whom a nodal metastasis was found at the time of surgery. Survival was not related to the size of nodal metastases in the occult metastases and single node positive groups. Some previous studies have found a worse prognosis associated with occult metastases on univariate analysis, but the evidence that it is an independent prognostic factor on multivariate analysis is weak. We believe that the current evidence does not support the routine use of serial sections or immunohistochemistry for the detection of occult metastases in the management of lymph node negative patients, but that the traditional factors of histological grade and tumour size are useful.

Retention of the expression of E-cadherin and catenins is associated with shorter survival in grade III ductal carcinoma of the breast

Many studies have investigated the relationship between the E‐cadherin/catenin axis and breast cancer biology and yet, unlike the studies in other tumour systems, which have shown a relationship between down‐regulation and poor survival, no clear association has emerged in breast. Since accumulating evidence suggests that ductal carcinoma of no special type (NST) represents a diverse group of biologies, this study has focused on grade III ductal carcinoma, in order to reduce the heterogeneity of the study population. A total of 470 breast tumours were studied. Consecutive sections were labelled with antibodies which recognize E‐cadherin and the arm proteins with which it interacts: α‐, β‐, and γ‐catenin. Membrane‐bound and cytoplasmic E‐cadherin and membrane‐bound α‐catenin expression were associated with a positive oestrogen receptor (ER) status, γ‐catenin with a negative ER status, and, surprisingly, all three with poor survival. Taken together, these findings suggest that a conserved E‐cadherin/catenin axis may play a part in determining adverse outcome in grade III breast carcinoma. Copyright

Different patterns of inflammation and prognosis in invasive carcinoma of the breast.

Aim : Inflammation in carcinoma of the breast may represent an immune response to the tumour, but there is evidence that this response is impaired. Inflammation may also stimulate tumour growth by releasing proteolytic enzymes and angiogenic factors. Prognostic studies have produced conflicting results, but most investigators have not evaluated the different patterns of inflammation. The aim of this study was to test the hypothesis that moderate or marked diffuse inflammation is associated with a better prognosis. We also tested the ‘danger model’, which suggests that necrosis is necessary for an effective immune response.

The pattern of expression of the microtubule‐binding protein RHAMM/IHABP in mammary carcinoma suggests a role in the invasive behaviour of tumour cells

Intracellular hyaluronic acid binding protein (RHAMM/IHABP), which was recently identified as a novel member of the microtubule‐associated protein (MAP) family, has the capacity to interact not only with microtubules but also with microfilaments. The molecule, which is known to be expressed in mammary carcinoma cells, might, through virtue of its intracellular interactions, influence tumour cell morphology and motility. This possibility was examined in a series of 189 mammary carcinomas by immunohistochemistry, using a polyclonal antibody to RHAMM/IHABP. Tumours were selected to include approximately equal numbers of consecutive grade I, II and III ductal carcinomas and invasive lobular carcinomas. Higher grade tumours had significantly lower expression of RHAMM/IHABP in the cytoplasm (p=0.02), but significantly increased expression in trabeculae (p=0.002) and further enhancement at the tumour island edges (p=0.002). Tumours of infiltrating lobular type had stronger expression in the overall cytoplasm (p=0.02) and trabeculae (p=0.08) than carcinomas of ductal type. The presence of strong trabecular expression was associated with a reduced overall survival time (p=0.017). These results suggest that RHAMM/IHABP expression may contribute to the motility and invasiveness of a tumour cell sub‐population in breast cancers. Copyright

BAG-1 expression in human breast cancer: interrelationship between BAG-1 RNA, protein, HSC70 expression and clinico-pathological data

BAG‐1 (BCL‐2 athanogene‐1), a multifunctional protein which associates with steroid hormone receptors (including the oestrogen receptor) and the anti‐apoptotic BCL‐2 protein, regulates steroid hormone‐dependent transcription and apoptosis. Direct interaction with 70 kD heat‐shock proteins, HSC70 and HSP70, may mediate the diverse functions of BAG‐1. Immunohistochemistry was used to examine the expression of BAG‐1 and HSC70 in 160 cases of invasive breast cancer. BAG‐1 was expressed in 92% of cases; most tumours exhibited cytoplasmic BAG‐1, while a smaller proportion also had nuclear immunostaining. There was a significant inverse correlation between histological grade and nuclear BAG‐1 expression, with higher‐grade tumours tending to have reduced nuclear BAG‐1 expression, but there was no association with cytoplasmic BAG‐1. There was also no significant correlation between nuclear or cytoplasmic BAG‐1 expression and oestrogen receptor positivity. Since BAG‐1 may be influenced by hormonal background, the relationship between grade and oestrogen receptor was examined separately in pre‐menopausal and post‐menopausal women. The statistically significant correlation between nuclear BAG‐1 expression and low tumour grade was strong in pre‐menopausal, but not apparent in post‐menopausal women. A statistically significant correlation was observed between cytoplasmic, but not nuclear, BAG‐1 expression and oestrogen receptor status in pre‐menopausal, but not post‐menopausal, women. There was no correlation between BAG‐1 protein expression and RNA, suggesting that important post‐transcriptional mechanisms control BAG‐1 expression in vivo. HSC70 was also detected in the majority (97%) of cases, although expression was not correlated with BAG‐1 levels, oestrogen receptor status or tumour grade. Overall survival in cases with high levels of nuclear BAG‐1 expression was improved, though not significantly. These results are consistent with the hypothesis that BAG‐1 plays an important but variable role in breast cancers developing in pre‐menopausal and post‐menopausal women. Copyright

Mitotic counts provide additional prognostic information in grade II mammary carcinoma

The ability to predict how long a patient diagnosed with breast cancer is likely to survive is still imprecise, despite numerous studies which have identified potential prognostic markers. The ‘established’ markers such as nodal status, tumour size, and histological grade have been used for many years and certainly provide some degree of accuracy upon which treatment can be based. However, women with similar prognostic features can vary significantly in their outcome and very few of the newly identified markers provide information that is sufficiently useful to warrant the time and expense spent on their evaluation. In a cohort of 145 women, an assessment has been made of whether knowledge of the proliferative activity of grade II infiltrating ductal breast carcinomas can improve the accuracy of predicting clinical outcome for individual patients. Use of the mitotic count (MC), which was assessed as part of the grading system, enabled patients to be stratified into ‘good’ and ‘bad’ prognostic groups. The measurement of S‐phase fraction using flow cytometry gave a similar result, but has the disadvantage that the technique requires specialized equipment. The evaluation of Ki‐67 expression using immunohistochemistry was of no additional prognostic value in this defined group. It is proposed that MC, used once to establish grade, could be used again amongst the grade II tumours to improve the accuracy of prognosis and thus influence treatment strategies with minimal additional effort or expense. Copyright

Ductal in situ Component and Prognosis in Invasive Mammary Carcinoma

Nearly 10 years ago we reported the close agreement present between the level of differentiation of the in situ component and that of the invasive component in ductal carcinomas containing both elements (p ≤ 0.001) [1]. This finding has since been confirmed by others [2, 3]. We also noted the significant correlation between the degree of differentiation of the in situ component and prognosis. Indeed, at the time of the study the 14 patients with tumours containing well differentiated ductal carcinoma in situ (DCIS) were all alive and disease free. This association between the grade of the in situ component of invasive carcinomas and prognosis has also been confirmed [4]. Furthermore, a recent report of a randomised trial of patients with pure DCIS found that the histological type of the initial DCIS predicted outcome of subsequently developing invasive disease; those with poorly differentiated DCIS being at a four-fold increased risk of death from metastatic breast cancer [5]. We therefore thought it would be interesting to do a further follow up of our study group. As shown in Figure 1, after a median follow up of 11.2 years (range 0.1–23.6 years), there is still a strongly significant correlation between survival and the differentiation of the DCIS component (p = 0.0002). None of the patients with well differentiated DCIS have died and apart from one who developed a contralateral mammary carcinoma after 23 years they are all still disease free. It would appear that the presence of a well differentiated DCIS associated with an invasive tumour is indicative of a very favourable prognosis. Could this be a possible marker for identifying patients who do not require adjuvant therapy?

Paget's disease of the nipple: A multi-focal manifestation of higher risk disease

BACKGROUND The treatment of Paget disease by mastectomy has been challenged recently in favor of breast-conserving techniques. A large series of patients treated with mastectomy has been reviewed to assess the feasibility of less radical surgery. METHODS The cases of 70 women with a clinical diagnosis of Paget disease were reviewed. The type, grade, receptor and node status, and the mammographic and pathologic extent of the underlying breast malignancy were determined. The survival of patients with invasive disease was compared with matched controls without Paget disease. RESULTS The underlying malignancy was invasive in 58% of cases. Despite the fact that only one third of women presented with a palpable mass, the malignancy was frequently extensive, being confined to the retroareolar region in only 25% of cases. The true extent of the disease was underestimated by mammography in 43% of cases. Of the patients with ductal in situ carcinoma, 96.5% had high-grade carcinomas and 100% had invasive carcinomas of high cytonuclear grade. Overexpression of the c-erb-B2 oncogene was detectable in 83% of cases. Patients with Paget disease had a significantly worse survival than matched controls, but this difference was eliminated if they were also matched for c-erb-B2 status. CONCLUSIONS Paget disease is often associated with extensive underlying malignancy, which is difficult to assess accurately either clinically or mammographically. As a consequence, cone excision of the nipple would have resulted in incomplete excision in 75% of cases. The underlying disease is of high grade and is frequently c-erb-B2 positive with a resulting poor prognosis. Aggressive local and systemic treatment would seem to be merited.