Relationship between Cambrl Expression and Tumor Progression in Small cell Lung Carcinomas

Expression of Two Antigens Defined by Monoclonal Antibodies in Normal, Benign and Malignant Human Mammary Tissues

We examined the reactivity of two monoclonal antibodies (MAbs), MBrl and MBr8, on sections from normal breast tissues, benign lesions, primary infiltrating carcinomas and distant breast cancer metastases and compared the expression of the recognized antigens (CaMBr1 and CaMBr8 respectively) in these different normal and pathologic conditions. The expression of both antigens was found to significantly decrease in the neoplastic tissues, in comparison to normal breast tissue (34% vs 61% for MBr1 and 52% vs 86% for MBr8; p < 0.001 for both). Atypical epithelial hyperplasia was found to be reactive on the same level (31%) of the tumors when tested with MBr1, whereas its reactivity was similar to that of normal tissues (78%) when MBr8 was used. Non-atypical epithelial hyperplasia showed the same reactivity with both MAbs (positive staining on about 50% of the cells). 65% of the « in situ » ductal carcinoma cases was MBr1-positive, whereas 50% was MBr8-positive; these values, when compared with the reactivity on normal glands, were significantly lower for MBr8, but not for MBr1. When testing sections from premenopausal women who had biopsies performed on different days during their menstrual cycle a correlation was found between the expression of CaMBr1 in normal breast epithelial cells and the stimulatory phase of the cycle. These findings suggest that both antigens are typical of normal breast and their expression could possibly decrease in pathologic tissues.

Description of a New Monoclonal Antibody, FC-2.15, Reactive with Human Breast Cancer and other Human Neoplasias

FC-2.15 is an IgM monoclonal antibody (MAb) obtained by immunizing Balb/c mice with tumor epithelial cells from a human undifferentiated primary breast carcinoma. FC-2.15 reacts with 93.9% (31/33) of human breast primary tumors, independently of their histology and hormone receptor content. Moreover, FC-2.15 reacts with 79.6 ± 13.8% (mean ± SD) of total breast malignant tumor cells and with 88.7 ± 9.9% of proliferating tumor cells. It recognizes other neoplasia such as colon cancer, squamous carinoma and melanoma. Among the normal tissues examined, strong cross-reactivity was found with kidney proximal convolute tubules, bone marrow myeloid progeny, peripheral granulocytes and large bowel epithelium. Through Western blots, FC-2.15 recognizes three major bands of Mr 160 kDa, 130 kDa and 115 kDa in membrane extracts of MCF-7 cells grown in nude mice and of human breast carcinoma and three major bands of 250 kDa, 185 kDa and 105 kDa in membrane extracts of peripheral granulocytes. This MAb mediates complement- cytotoxicity against malignant cells, reducing the clonogenic capacity of breast primary tumor cells and MCF-7 cells to 35.6 ± 41.2% and 11.7 ± 4.8 % of control values respectively, whereas that of normal bone marrow cells is not affected (104.7 ± 17.4%).

Expression of Globo H and SSEA3 in breast cancer stem cells and the involvement of fucosyl transferases 1 and 2 in Globo H synthesis

We examined the expression in breast cancer stem cells (BCSCs) of Globo H, a potential tumor-associated antigen for immunotherapy of epithelial cancers including breast cancer. Flow cytometry revealed Globo H expression in 25/41 breast cancer specimens (61.0%). Non-BCSCs from 25/25 and BCSCs from 8/40 (20%) expressed Globo H. We showed the expression of stage-specific embryonic antigen 3 (SSEA3), the pentasaccharide precursor of Globo H, in 31/40 (77.5%) tumors. Non-BCSCs from 29/40 [corrected] and BCSCs from 25/40 (62.5%) expressed SSEA3. Like Globo H, SSEA3 expression in normal tissues was predominately at the secretory borders of epithelium, where access to the immune system is restricted. Immunization of mice with Globo H-KLH and alpha-GalCer induced antibodies reactive with Globo H and SSEA3, suggesting that a Globo H-based vaccine will target tumor cells expressing Globo H or SSEA3. We next sought to reduce Globo H expression by siRNA targeting fucosyltransferase (FUT) 1 and 2, which mediate alpha-1,2 linkage of fucose to SSEA3 to generate Globo H. We showed both genes to be involved in the biosynthesis of Globo H. Moreover, FUT2 expression in BCSCs was significantly lower than in non-BCSCs harvested from a primary human breast cancer in NOD/SCID mouse, whereas FUT1 was slightly lower in BCSCs. Thus, the lower expression of Globo H in BCSCs may be attributed to less FUT2/FUT1, and to reduced SSEA3 in BCSCs compared with non-BCSCs. Our findings provide insight into further development of a Globo H-based vaccine and FUT1/FUT2-targeted therapy for breast cancer.

ABH and Lewis histo-blood group antigens in cancer

Antigens of the ABH and Lewis histo-blood group family can be found on many normal cells, mainly of epithelial type. In carcinomas, altered expression of the various carbohydrate epitopes of this family occur, and are often strongly associated with either a good or bad prognosis. A review of the available data on these tumor-associated markers, their biosynthesis and their prognostic value is proposed here. For a long time it has been unclear whether their presence could affect the behavior of carcinoma cells. Recent data, however, indicate that they play biological roles in the course of tumor progression. The presence of sialyl-Le(a) or sialyl-Le(x), which are ligands for selectins, promotes the metastatic process by facilitating interaction with the endothelium of distant organs. The loss of A and B antigens increases cellular motility, while the presence of H epitopes increases resistance to apoptosis by mechanisms that remain to be defined. The Le(y) antigen has procoagulant and angiogenic activities. All these observations are used to present a model that may account for the described associations between the presence or loss of these markers and the outcome of disease. Finally, their potential clinical applications as tumor-associated markers or as targets of immunotherapy are reviewed.

Prognostic significance of the CaMBr1 antigen on breast carcinoma: relevance of the type of recognised glycoconjugate

An extensive study of the expression of the blood group-related antigen CaMBr1 has been performed by immunohistochemistry, immunoblotting and high performance thin layer chromatography both on frozen and paraffin-embedded (paraffin) samples from normal and neoplastic breast tissues. The glycolipid antigenic fraction (from frozen samples) was preferentially expressed on functioning breast epithelium. In a prospective series of 143 breast cancer cases CaMBr1 expression was associate, on frozen sections, with the transferrin receptor (P = 0.01), the positivity with oestrogen receptor immunochemical assay (P = 0.06), premenopausal status (P = 0.06) and node negativity (P = 0.07). Non-significant correlation with longer disease-free survival (DFS) was observed. In a retrospective series of 862 cases on paraffin sections the glycoproteic antigenic fraction was significantly associated with premenopausal status (P < 0.05) and lobular histotype (P < 0.01), but failed to predict survival, although a trend for longer DFS was observed for positive cases.

Study of the expression and function of the tumour-associated antigen CaMBr1 in small cell lung carcinomas

The expression of the epithelial antigen recognised by the MBr1 monoclonal antibody (CaMBr1) was studied on 161 small cell lung carcinoma (SCLC) biopsies. A correlation between the marker expression and the overall survival of the patients was found. To investigate the possible role of CaMBr1 in tumour aggressiveness, the in vivo and in vitro growth capabilities of different SCLC cell lines, in relation to the antigen expression, were analysed. The CaMBr1-positive cell lines displayed a higher growth potential in comparison to CaMBr1-negative cells. The biochemical nature of CaMBr1 was analysed in terms of enzyme sensitivity, molecular weight and comparison with other glycoproteins expressed by SCLC cells. The results indicated the trypsin sensitivity of the molecule, and sialic acid hiding of the CaMBr1 epitope. The increase of MBr1 reactivity after neuraminidase treatment suggests that the CaMBr1 epitope expressed in the SCLC cell line is carried by a sialoglycoprotein.

The possibility of applying a monoclonal tumor-restricted antibody in cytologic diagnosis of lung cancer in serous effusions

Fifty serous effusions resulting from a lung disease have been examined. A tumor-restricted anticarcinoma of the lung (not a small cell lung carcinoma) MAb, termed HuTu-m3, has been used together with conventional cytology to examine the cells. The results achieved by immunocytochemical examination have been compared with cytologic results and the data obtained have been evaluated in terms of sensitivity, specificity, predictive value and test efficiency. The final analysis suggests that this technique might be helpful in the diagnosis of serous effusions by increasing the sensitivity of cancer cell cytologic detection.