The biological, clinical and prognostic implications of p53 transcriptional pathways in breast cancers.

We hypothesized that the functional status of p53 transcriptional pathways, rather than p53 protein expression alone, could accurately discriminate between low- and high-risk breast carcinoma (BC) and inform about individuals' tumour biological behaviour. To test this, we studied a well-characterized series of 990 BCs with long-term follow-up, immunohistochemically profiled for p53, its main regulators and downstream genes. Results were validated in an independent series of patients (n = 245) uniformly treated with adjuvant anthracycline-based chemotherapy. Eleven p53 transcriptional phenotypes were identified with just two main clinical outcomes. (a) Low risk/good prognosis group (active/partially inactive p53 pathways), defined as p53(+/-)/MDM4(+)/MDM2(+/-)/Bcl2(+/-)/p21(+/-), p53(-)/MDM4(-)/MDM2(+)/Bcl2(+)/p21(+/-) and p53(+/-)/MDM4(-)/MMD2(-)/Bcl2(+)/p21(+/-). These tumours had favourable clinicopathological characteristics, including ER(+) and long survival after systemic adjuvant-therapy (AT). (b) High risk/poor prognosis group (completely inactive p53 pathways), defined as p53(+/-)/MDM4(-) MDM2(-)/Bcl2(-)/p21(-), p53(-)/MDM4(-) MDM2(+)/Bcl2(-)/p21(-) and p53(+/-)/MDM4(-)/MDM2(-)/Bcl2(-)/p21(+). These tumours were characterized by aggressive clinicopathological characteristics and showed shortened survival when treated with AT. Completely inactive p53 pathways but intact p21 axis p53(+/-)/MDM4(-)/MDM2(-)/Bcl2(-)/p21(+) had the worst prognosis, particularly patients who received AT. Multivariate Cox regression models, including validated prognostic factors for both test and validation series, revealed that the functional status of p53 transcriptional pathways was an independent prognosticator for BC-specific survival (HR 2.64 and 4.5, p < 0.001, respectively) and disease-free survival (HR 1.93 and 2.5, p < 0.001, respectively). In conclusion, p53 functional status determined by assessment of p53 regulatory and downstream targets provides independent prognostic value and may help determine more adequate therapeutic regimens for specific subgroups of breast cancer patients.

The biological and clinical characteristics of breast carcinoma with mixed ductal and lobular morphology.

UNLABELLED: Although invasive ductal (IDC) and lobular (ILC) breast carcinomas are well characterised in the literature, the biological and clinical significance of mixed tumours with both ductal and lobular components has not been investigated. In the current study, we have examined a well-characterised series of breast carcinoma with a long term follow-up that comprised 140 mixed tumours, 2170 IDC and 380 pure ILC. RESULTS: Mixed tumours constituted 3.6% of all cases. The majority (59%) of the mixed tumours were grade 2 compared to 33% in IDC and 88% in ILC. Positive lymph nodes (LN) were found in 41% and definite vascular invasion (VI) in 26% of the cases. DCIS was detected in 123 (89%) and LCIS in 43 (31%) (both DCIS and LCIS were found in 39 cases). The majority of tumours were predominantly (>50 of tumour area) of ductal type (57%). When compared to pure IDC, mixed tumours showed an association with lower grade, ER positivity and lower frequency of development of distant metastases. When compared to pure ILC, mixed tumours showed an association with higher grade, positive LN metastasis, VI and development of regional metastasis. After adjustment for grade most of these differences were no longer apparent. There was an association between histologic type of carcinoma in LN metastasis and the predominant histologic type of the primary tumour. Mixed tumours showed metastatic patterns similar to that of ILC with frequent metastasis to bone. No clinically meaningful differences in survival were found between these mixed carcinomas and pure IDC or ILC of the breast or between mixed tumours with predominantly ductal or lobular phenotype.

Basal phenotype identifies a poor prognostic subgroup of breast cancer of clinical importance.

BACKGROUND: Breast cancer is recognised to be a heterogeneous disease with a range of morphological appearances and behaviours. The recently recognised basal phenotype (BP) is associated with poor survival, but the clinical implications of this class of breast cancers remain to be adequately defined. METHODS: We have examined a well-characterised series of 1872 invasive breast carcinomas with a long term follow-up to assess the clinical significance of BP. RESULTS: A pragmatic definition of the BP as immunophenotypic evidence of basal cytokeratins CK5/6 and/or CK14 expression was used. These tumours were associated with shorter overall survival and disease-free interval in our series as a whole and in both the lymph node (LN) negative and LN positive subgroups. When stratified by histological grade, BP was of highly significant prognostic value in grade 3 but not in grades 1 or 2 tumours. Similarly, it was associated with poor survival in the moderate group of the Nottingham prognostic Index but not in the other groups. In a subgroup comprising LN negative grade 3 tumours, BP was the most powerful prognostic marker followed only by tumour size, while the other variables were non-significant. Patients with BP were more likely to respond to chemotherapy than those with non-basal tumours. CONCLUSIONS: Our results provide robust evidence that BP is an important class of breast cancers with a particularly aggressive behaviour in patients with LN negative grade 3 disease. We recommend routine identification of BP in breast cancer and the development of effective adjuvant treatment strategies. These are important observations as these tumours typically lack hormone receptor and HER-2 overexpression limiting the range of relevant adjuvant therapies.

Selective use of post-mastectomy flap irradiation in high-risk breast cancer patients.

The incidence of local recurrence after mastectomy can be reduced by chest wall radiotherapy. However, only a minority of patients are at substantial risk. No UK national guidelines exist for the use of mastectomy flap radiotherapy. This study evaluated a protocol, whereby only high-risk patients were treated with post-mastectomy flap radiotherapy; identified histologically by grade, vascular invasion and nodal status. All women treated by simple mastectomy for invasive breast cancer at the Nottingham Breast Unit from January 1993 to December 1995 were studied (n=292). Postoperative flap radiotherapy was given to 147 high-risk women (50.3%). Median follow-up was 76 months. Overall, 12 women (4.1%) developed a chest wall recurrence; six were single spot recurrences and the remaining six were either multiple spot (n=3) or field change (field change dermal invasion, n=3). The chest wall recurrence rate was 2.7% in those treated with radiotherapy. A low rate of local recurrence has been achieved with selective use of mastectomy flap radiotherapy.

Tubular carcinoma of the breast: further evidence to support its excellent prognosis.

PURPOSE Although tubular carcinoma (TC) is known to have a favorable prognosis, it is still unknown whether this subtype represents a distinct type of breast carcinoma or whether it behaves like other low-grade luminal A-type breast carcinomas. METHODS In this study, we performed a retrospective analysis of a large well-characterized series of breast cancers (2,608 carcinomas) to assess the clinicopathologic and molecular features and prognostic value of TC compared with grade 1 ductal carcinomas of the breast. Results When compared with grade 1 ductal carcinoma (n = 212), TC (n = 102) was more likely to be detected on mammographic screening, had smaller median size, and less frequently showed lymphovascular invasion. Compared with grade 1 ductal carcinoma, TC was associated with longer disease-free survival (chi(2) = 13.25, P < .001) and breast cancer-specific survival (chi(2) = 8.8, P = .003). In this study, none of the patients with TC developed distant metastasis or died from the disease without an intervening recurrence as invasive carcinoma of different histologic type. CONCLUSION We conclude that the biologic behavior of TC is excellent and is more favorable than that of grade 1 ductal carcinoma. Patients with TC may be at risk of developing second primary carcinomas in the contralateral breast, which may be of higher grade and poorer potential prognostic outcome. In addition, patients with TC seem to have a close to normal life expectancy, and as a consequence, adjuvant systemic therapy may not be justified in their routine management.

A methodology to identify consensus classes from clustering algorithms applied to immunohistochemical data from breast cancer patients.

Single clustering methods have often been used to elucidate clusters in high dimensional medical data, even though reliance on a single algorithm is known to be problematic. In this paper, we present a methodology to determine a set of 'core classes' by using a range of techniques to reach consensus across several different clustering algorithms, and to ascertain the key characteristics of these classes. We apply the methodology to immunohistochemical data from breast cancer patients. In doing so, we identify six core classes, of which several may be novel sub-groups not previously emphasised in literature.

Prognostic significance of Nottingham histologic grade in invasive breast carcinoma.

PURPOSE: The three strongest prognostic determinants in operable breast cancer used in routine clinical practice are lymph node (LN) stage, primary tumor size, and histologic grade. However, grade is not included in the recent revision of the TNM staging system of breast cancer as its value is questioned in certain settings. MATERIALS AND METHODS: This study is based on a large and well-characterized consecutive series of operable breast cancer (2,219 cases), treated according to standard protocols in a single institution, with a long-term follow-up (median, 111 months) to assess the prognostic value of routine assessment of histologic grade using Nottingham histologic grading system. RESULTS: Histologic grade is strongly associated with both breast cancer-specific survival (BCSS) and disease-free survival (DFS) in the whole series as well as in different subgroups based on tumor size (pT1a, pT1b, pT1c, and pT2) and LN stages (pN0 and pN1 and pN2). Differences in survival were also noted between different individual grades (1, 2, and 3). Multivariate analyses showed that histologic grade is an independent predictor of both BCSS and DFS in operable breast cancer as a whole as well as in all studied subgroups. CONCLUSION: Histologic grade, as assessed by the Nottingham grading system, provides a strong predictor of outcome in patients with invasive breast cancer and should be incorporated in breast cancer staging systems.

High-throughput protein expression analysis using tissue microarray technology of a large well-characterised series identifies biologically distinct classes of breast cancer confirming recent cDNA expression analyses.

Recent studies on gene molecular profiling using cDNA microarray in a relatively small series of breast cancer have identified biologically distinct groups with apparent clinical and prognostic relevance. The validation of such new taxonomies should be confirmed on larger series of cases prior to acceptance in clinical practice. The development of tissue microarray (TMA) technology provides methodology for high-throughput concomitant analyses of multiple proteins on large numbers of archival tumour samples. In our study, we have used immunohistochemistry techniques applied to TMA preparations of 1,076 cases of invasive breast cancer to study the combined protein expression profiles of a large panel of well-characterized commercially available biomarkers related to epithelial cell lineage, differentiation, hormone and growth factor receptors and gene products known to be altered in some forms of breast cancer. Using hierarchical clustering methodology, 5 groups with distinct patterns of protein expression were identified. A sixth group of only 4 cases was also identified but deemed too small for further detailed assessment. Further analysis of these clusters was performed using multiple layer perceptron (MLP)-artificial neural network (ANN) with a back propagation algorithm to identify key biomarkers driving the membership of each group. We have identified 2 large groups by their expression of luminal epithelial cell phenotypic characteristics, hormone receptors positivity, absence of basal epithelial phenotype characteristics and lack of c-erbB-2 protein overexpression. Two additional groups were characterized by high c-erbB-2 positivity and negative or weak hormone receptors expression but showed differences in MUC1 and E-cadherin expression. The final group was characterized by strong basal epithelial characteristics, p53 positivity, absent hormone receptors and weak to low luminal epithelial cytokeratin expression. In addition, we have identified significant differences between clusters identified in this series with respect to established prognostic factors including tumour grade, size and histologic tumour type as well as differences in patient outcomes. The different protein expression profiles identified in our study confirm the biologic heterogeneity of breast cancer and demonstrate the clinical relevance of classification in this manner. These observations could form the basis of revision of existing traditional classification systems for breast cancer.