Lisa C. Happerfield

Nitric oxide synthase activity in human breast cancer.

Nitric oxide (NO) is generated by a family of isoenzymes (NO synthases) expressed in a wide range of mammalian cells. We have recently reported NO synthase expression in human gynaecological cancers. In this study we have assessed the activity and distribution of NO synthase in a series of human breast tumours and in normal breast tissue. Calcium-dependent (constitutive) and -independent (inducible) NO synthase activity, as well as NO biosynthesis, was high in invasive tumours compared with benign or normal tissue. Furthermore, for invasive ductal carcinomas, NO biosynthesis was significantly greater for grade III compared with grade II tumours. Immunohistochemical investigations revealed immunolabelling with a monoclonal antibody to murine inducible NO synthase predominantly within tumour-associated macrophages. Immunolabelling with a polyclonal antiserum raised against rat brain NO synthase was also observed in vascular endothelial and myoepithelial cells. Thus NO synthase is expressed in human breast tumours, where its presence correlates with tumour grade.

Molecular classification of breast carcinomas using tissue microarrays.

The histopathologic classification of breast cancer stratifies tumors based on tumor grade, stage, and type. Despite an overall correlation with survival, this classification is poorly predictive and tumors with identical grade and stage can have markedly contrasting outcomes. Recently, breast carcinomas have been classified by their gene expression profiles on frozen material. The validation of such a classification on formalin-fixed paraffin-embedded tumor archives linked to clinical information in a high-throughput fashion would have a major impact on clinical practice. The authors tested the ability of tumor tissue microarrays (TMAs) to sub-classify breast cancers using a TMA containing 107 breast cancers. The pattern of expression of 13 different protein biomarkers was assessed by immunohistochemistry and the multidimensional data was analyzed using an unsupervised two-dimensional clustering algorithm. This revealed distinct tumor clusters which divided into two main groups correlating with tumor grade (P <0.001) and nodal status (P = 0.04). None of the protein biomarkers tested could individually identify these groups. The biological significance of this classification is supported by its similarity with one derived from gene expression microarray analysis. Thus, molecular profiling of breast cancer using a limited number of protein biomarkers in TMAs can sub-classify tumors into clinically and biologically relevant subgroups.

The localization of the insulin-like growth factor receptor 1 (IGFR-1) in benign and malignant breast tissue.

Insulin‐like growth factors (IGFs) play an important role in normal cellular growth and development and have been implicated in the regulation of tumour growth. Two receptors are recognized, IGFR‐1 and IGFR‐2, of which one, IGFR‐1, is a transmembrane heterodimer structurally similar to the insulin receptor. Studies using ligand‐binding assays have suggested that the proportion of human breast carcinomas expressing IGFR‐1 varies between 39 and 93 per cent and all suggest a lower level of IGFR‐1 expression in benign mammary epithelia. As there is this variation between studies and since no study appears to have examined the immunohistochemical localization of IGFR‐1 within breast tissue, a series of 79 infiltrating ductal carcinomas, 11 infiltrating lobular carcinomas, three cases of pure ductal carcinoma in situ (DCIS), seven fibroadenomas, and eight normal breast specimens have been studied utilizing the monoclonal antibody αIR3. IGFR‐1 localized to the epithelial component of 90 per cent of the carcinomas, with only cytoplasmic (21 per cent), only membrane (5 per cent), or a mixture of both cytoplasmic and membrane (64 per cent) staining patterns. In some tumours, distinct basolateral distribution of the receptor was observed. Invasive lobular carcinoma showed significantly less labelling than ductal (P=0·0009). There was a significant correlation between the level of IGFR‐1 immunostaining with both oestrogen receptor (P<0·001) and progesterone receptor (P=0·0018) positivity within the malignant group. All normal mammary epithelium showed strong labelling, which was often at an intensity matching that of the most strongly labelled carcinoma and occasionally visualized as basolateral staining of the luminal cells. Weak to moderate staining of endothelial cells was also observed. It is concluded that IGFR‐1 immunoreactivity is found in the majority of breast carcinomas, where it correlates most closely with oestrogen receptor status. The high intensity labelling of normal cells seen in this study contrasts with the low levels inferred from ligand‐binding‐based techniques and emphasizes the importance of the morphological approach in the investigation of novel molecules.

Expression of sialyl-Tn predicts the effect of adjuvant chemotherapy in node-positive breast cancer.

Sialyl-Tn (STn) is a carcinoma-associated carbohydrate determinant expressed on cancer-associated mucins and has the structure NANA alpha(2-6)alpha GalNAc. Expression of STn in colon and ovarian cancer is associated with a poor prognosis independent of tumour grade, stage or histological type. We have examined 237 cases of primary breast cancer for expression of this antigen using the antibody HB-STn (Dako). The frequency of STn expression was 31% in the whole group, 36% in the node-negative and 28% in the node-positive group. Survival was lower, but not significantly so, in the STn-positive group (P = 0.07), but this effect was highly significant for patients with node-positive disease (P < 0.002), the curves for node-negative disease being coincident (P = 0.31). In node-positive disease the effect was limited to those receiving adjuvant chemotherapy (P = 0.001). In a multivariate (Cox) analysis on the whole group STn staining, combined with adjuvant chemotherapy, showed a highly significant correlation with survival. In STn-negative cases, adjuvant chemotherapy improved survival (relative risk 2.3, 95% confidence intervals 1.4-3.9), whereas adjuvant chemotherapy did not influence survival in patients which expressed STn (relative risk 1.1, 95% confidence intervals 0.6-2.2). Thus, by either direct or indirect mechanisms, STn positivity appears to be a marker of resistance to adjuvant chemotherapy.

Angiogenesis and inflammation in ductal carcinoma in situ of the breast

Several recent studies suggest that vascular density may be an independent prognostic indicator in invasive carcinoma of the breast. Increased vascularity has also been shown in ductal carcinoma in situ (DCIS). The prognostic significance of the inflammatory infiltrate in mammary carcinoma is more controversial, but it could affect angiogenesis by releasing angiogenic factors and digesting matrix. Vascularity and inflammation have been studied in 41 examples of pure DCIS, classified using the method of Holland et al. Immunohistochemistry was performed with antibodies to von Willebrand factor, CD3, CD8, CD45RO, CD45RA, CD20, CD68, and c‐erbB‐2. The main pattern of inflammation was clusters of B and T cells situated either adjacent to involved ducts or in the interductal stroma. Typically, these clusters were around vessels with plump endothelium suggestive of high endothelial venules. A less prominent pattern was a diffuse stromal infiltrate of macrophages and T cells. There were two patterns of increased vascularity associated with DCIS: necklaces of vessels close to the involved ducts and vessels arranged diffusely in the interductal stroma. Each pattern of inflammation and of vascularity was graded semi‐quantitatively. Increased stromal vascularity was associated with the perivascular clusters of inflammation; both were associated with c‐erbB‐2 expression and extent of the DCIS. Necklaces of vessels were associated with the diffuse inflammation. Perivascular inflammation and c‐erbB‐2 (but neither pattern of vascularity) were associated with poor differentiation of the DCIS. Thus, different patterns of inflammation are associated with different patterns of vessels. The clusters of B and T cells may be recruited via high endothelial venules induced by the DCIS. Cytokines released by the DCIS and/or the inflammatory cells (clusters or diffuse) may stimulate the two patterns of new vessel formation.

Inflammatory infiltrate in invasive lobular and ductal carcinoma of the breast.

The significance of inflammation in carcinoma of the breast is controversial. Little attention has been paid to different patterns of inflammation or inflammation associated with different histological types of carcinoma. We have looked at the pattern of inflammation in 123 invasive mammary carcinomas (including 46 lobular), and characterised the inflammatory cells with immunohistochemistry in 21. We found different patterns of inflammation in ductal and lobular carcinoma. Diffuse inflammation was seen more in ductal carcinoma, particularly of high grade, and was predominantly composed of macrophages and T cells. It was associated with necrosis, but the correlation was weak, suggesting that other factors are important. Perilobular inflammation was seen most frequently in lobular and high-grade ductal carcinomas, particularly at the tumour edge. Perivascular inflammation was also largely at the tumour edge, but was not more common in any tumour type. In contrast to the diffuse inflammation, the perivascular and perilobular inflammation was composed of T and B cells. Normal lobules at the tumour edge showed consistent expression of HLA-DR, whereas lobules away from the tumour were negative. A combination of perilobular and perivascular inflammation composed of B and T cells with epithelial expression of HLA-DR mimicking lymphocytic lobulitis was seen more frequently in lobular than ductal carcinoma.

c-erbB-3 protein expression in ductal carcinoma in situ of the breast.

c-erbB-3, A recently identified member of the type I tyrosine kinase receptor family, has been shown to be overexpressed in invasive ductal carcinoma of breast. In this study, expression of the c-erbB-3 protein was examined in 57 cases of pure ductal carcinoma in situ of the breast (DCIS) by immuno-cytochemical methods. Staining was either absent (17 cases), present at levels equivalent to that found in adjacent normal tissue (20) or greater than in normal tissue (20). In most cases the pattern of staining was cytoplasmic, but in 4 cases with the most intense reaction there was also focal membrane staining. In the same series of cases, c-erbB-2 protein had previously been shown to be overexpressed in 28 of 57 cases, c-erbB-2 overexpression was correlated with normal level of c-erbB-3, and lack of c-erbB-2 expression was correlated with c-erbB-3 overexpression.

In situ detection of human Ig light-chain mRNA on formalin-fixed and paraffin-embedded tissue sections using digoxigenin-labelled RNA probes

SummaryDigoxigenin-labelled RNA probes complementary to human immunoglobulin (Ig) kappa and lambda light-chain mRNAs were produced by in vitro transcription. Using these probes, several existing in situ hybridization protocols were studied. By modifying and optimizing pretreatment procedures, which include hybridization, stringency washings and probe detection, a simplified non-radioactive in situ hybridization method for Ig light-chain mRNAs was developed. The light-chain signals were consistently identified in plasma cells, germinal centrocytes, centroblasts and immunoblasts in formalin-fixed and paraffin-embedded sections of lymphoid tissues. Monotypic light-chain mRNA was demonstrated in archival cases of kappa or lambda light-chain-restricted B-cell lymphoma. Background staining was found to be negligible in all the tissues tested. These results indicate that the in situ hybridization methodology described in this study is specific and sensitive for the detection of Ig light-chain mRNAs and has practical value in routine histology.

Adhesion molecule expression and leucocyte trafficking following immunotherapy with recombinant interleukin‐2

The relevant anti‐tumour mechanisms of recombinant interleukin‐2 (rIL‐2) in vivo are unclear but an influx of T‐lymphocytes and macrophages has been noted in regressing lesions. One of the dose limiting toxicities of rIL‐2 is the development of a capillary leak syndrome attributed to widespread endothelial activation. Changes in expression of endothelial and leucocyte‐associated adhesion molecules were assessed in tumour and uninvolved skin in patients with metastatic breast cancer receiving rIL‐2. Increased expression of intracellular adhesion molecule‐1, its leucocyte‐associated ligand, leucocyte function associated molecule‐1, vascular cell adhesion molecule and its ligand, very late after activation antigen‐4 as well as members of the selectin family of adhesion molecules, were noted in uninvolved skin following rIL‐2. Expression of these adhesion molecules was noted in tumour stroma before rIL‐2 but little change was observed following rIL‐2 infusion. An influx of monocytes and T‐lymphocytes (expressing the IL‐2 receptor and of the memory subtype) and a lower number of neutrophils was noted in uninvolved skin following rIL‐2. Although monocytes and T‐lymphocytes were present in tumour stroma before rIL‐2 no changes were observed following infusion. The changes noted in the dermis contrast with those seen at tumour sites and may partly explain the low therapeutic index of rIL‐2.