Monoclonal antibody B72.3 in benign breast lesions.

It has been suggested that the monoclonal antibody B72.3 may be useful as a diagnostic tool in fine needle aspirates of breast masses because it recognises "tumour associated glycoprotein (TAG)-72". The antigen was sought in paraffin wax sections of 43 normal and benign breast biopsy specimens, using the avidin-biotin complex technique, to assess the extent of its presence in non-malignant tissue. Strong focal staining was seen in 21 (49%) cases. In 29 cases of fibrocystic change staining was present in 17 (59%). All areas of apocrine metaplasia were positive, as well as a few normal ducts and acini and occasional areas of adenosis. Focal positivity was present in five out of 12 foci of ductal epithelial hyperplasia and in three out of seven radial scars. Staining was absent in two areas of lobular hyperplasia, three areas of sclerosing adenosis, and in a focus of lactational change. Focal positivity was also seen in two out of five fibroadenomas and in two out of three intraduct papillomas. Five normal subareolar sections and a section of normal lactating breast were negative. It is concluded that B72.3 monoclonal antibody can show focal reactivity with a variety of normal and benign epithelial mammary structures, and it is doubtful that its use would be of any help in differentiating benign from malignant cells in fine needle aspirates.     

Comparative study of monoclonal antibody B72.3 and gross cystic disease fluid protein-15 as markers of apocrine carcinoma of the breast

Gross cystic disease fluid protein-15 (GCDFP-15) is a commonly used apocrine marker; however, its expression was recently found to decrease in infiltrating, larger, or metastasizing apocrine carcinomas of the breast. In the breast, monoclonal antibody (MAb) B72.3 has been reported to be useful as an apocrine marker although it is used for that purpose much less frequently than GCDFP-15. In the search for a more consistent apocrine marker, immunoreactivity for MAb B72.3 was examined in apocrine carcinomas at different stages and compared with GCDFP-15. 47 of 51 apocrine carcinomas (92%) and 9 of 62 ordinary carcinomas (15%) were MAb B72.3 positive, while 39 of 51 apocrine carcinomas (76%) and 13 of 62 ordinary carcinomas (21%) were GCDFP-15 positive. Thus, both sensitivity and specificity were higher for MAb B72.3. Furthermore, unlike GCDFP-15, MAb B72.3 exhibited positivity irrespective of infiltrating status, tumor size, or metastatic status. There was no correlation between MAb B72.3-immunoreactivity and GCDFP-15-expression. The combined usage of MAb B72.3 with GCDFP-15 was useful to confirm the diagnosis of apocrine carcinoma, especially for advanced tumors, with only two cases being negative for both MAb B72.3 and GCDFP-15. Whether these two cases should be differentiated from ordinary apocrine carcinomas remains to be investigated.     

Monoclonal antibody NCRC 11 reactivity with advanced breast carcinoma: lack of prognostic value

In a retrospective investigation tissue sections from 63 patients with advanced breast carcinoma (T3 and T4) were stained with the NCRC 11 antibody. The NCRC 11 staining intensity was correlated to survival. We did not find any prognostic value of the NCRC 11 staining among our patients with advanced breast carcinoma.     

Prostatic adenocarcinoma. Evaluation of immunoreactivity to monoclonal antibody B72.3

Monoclonal antibody B72.3 reacts with a tumor-associated glycoprotein designated TAG-72 that is expressed in many adenocarcinomas but not in normal tissues. The authors evaluated the immunoreactivity of B72.3 to benign, hyperplastic prostate, and to primary adenocarcinoma of the prostate to determine the frequency of TAG-72 production by benign and malignant prostatic epithelium. Focal cytoplasmic staining of gland cells was seen in 19 of 20 cases of glandular hyperplasia, and weak, homogeneous staining of secretions was seen in five cases. In contrast, 27 of the 35 (77%) adenocarcinomas studied showed at least focal intense staining of secretions, and 30 (86%) of the tumors showed some cytoplasmic immunostaining with B72.3. Positive staining occurred in all of the well-differentiated adenocarcinomas (100%) but was seen less often in moderately differentiated (82%) and poorly differentiated adenocarcinomas (58%). Because benign gland cells may express the TAG-72 antigen, immunohistochemistry results must be interpreted with caution and with regard to the overall morphologic pattern. Nonetheless, a positive B72.3 immunostain may be useful in identifying adenocarcinoma of the prostate, especially when an intense luminal reaction is found. A negative stain does not exclude the presence of adenocarcinoma, however.     

Critical evaluation of monoclonal antibody staining in breast carcinoma.

The immunoperoxidase staining of 84 primary invasive breast carcinomas with four monoclonal antibodies (BRST-1, HMFG1, EMA, B72.3) was evaluated by semiquantitative light microscopical examination and quantitative image analysis. Major differences in the staining of the tumours for each of the monoclonal antibodies was observed. Correlation between monoclonal antibody staining and patient age, survival, histological grade, tumour diameter and cellularity was also carried out. This showed a significant association between histological grade and staining with BRST-1 and EMA.     

Immunoperoxidase studies by monoclonal antibody B72.3 applied to breast aspirates: diagnostic considerations

The purpose of this study was to determine the reactivity of monoclonal antibody (MAb) B72.3 when applied directly to aspiration biopsy cytology (ABC) of the breast in the following conditions: (1) infiltration lobular carcinoma; (2) fibrocystic disease; (3) fibroadenoma; and (4) apocrine cysts. Nine of ten aspirates from infiltrating lobular carcinoma were positive in these assays, while 21 of 22 benign cases reacted negatively. The single false-positive benign aspirate manifested a staining pattern characteristic of apocrine cells. This study demonstrates that the MAb B72.3 can be employed as a potentially valuable diagnostic adjunct. It can be used on stained aspirates to assist in the interpretation of ABC from breast lesions.     

The value of monoclonal antibody B72.3 for the diagnosis of breast carcinoma: experience with the first commercially available source.

One hundred cases of invasive breast carcinoma were studied using the commercially available monoclonal antibody Anti-Human Tumor-Associated Glycoprotein-72 (MAb B72.3, Biomedical Technologies Inc, Stoughton, MA) prediluted at 8.5 micrograms/mL. Forty-three cases displayed positive reactivity with this antibody. Intensity and distribution of positive staining varied among the tumor cells. Twenty-two cases had 1% or less reactive cells, while eight cases contained 40% or more positive tumor cells. Apical cell membrane and diffuse cytoplasmic staining were present. In fifteen cases intracytoplasmic lumina and extra-cellular secretory material were highlighted by positive staining. Thirty-five cases had benign breast tissue adjacent to the tumor. Benign ductal and lobular epithelial cells were nonreactive except for two cases in which small foci of apocrine metaplasia were positive. Reactivity with MAb B72.3 was not dependent upon histologic grade, nuclear grade, nodal status, or patient age. Excluding the lower number of positively stained cases, our findings were similar to other MAb B72.3 investigations. The number of positively stained cases and the intensity of the positivity were increased by using MAb B72.3 at 5.0 micrograms/mL with overnight incubation, or by using MAb B72.3 at 40.0 micrograms/mL with 2 hours of incubation. Our findings confirm that MAb B72.3 shows reliable reactivity with breast carcinoma that is sensitive to antibody concentration and incubation time without loss of specificity for tumor cells. Our results are also consistent with the view that MAb B72.3 probably detects epithelial membrane-related antigens in breast carcinoma, as do several other antibodies.     

A tumor-associated antigen in carcinoma of the pancreas defined by monoclonal antibody B72.3

A retrospective analysis of 25 primary adenocarcinomas of the pancreas, 16 metastatic pancreatic tumors, 8 cases of chronic pancreatitis, and 3 adult normal pancreas was performed to ascertain the reactivity of monoclonal antibody (MAb) B72.3 to malignant and nonneoplastic pancreatic lesions. Formalin-fixed, paraffin-embedded sections of pancreas were evaluated by immunohistochemical techniques (avidin-biotin-peroxidase complex [ABC] method). Twenty-one of 25 malignant primary tumors were reactive, and all 16 metastatic sites expressed the B72.3 antigen. In contrast, all cases of pancreatitis and normal pancreas were either weakly reactive or nonreactive. Ten malignant and two benign pancreatic fine-needle aspirates provided results similar to those seen with fixed tissues. Because MAb B72.3 has selective reactivity for primary and metastatic pancreatic cancer, it may be of value as a diagnostic adjunct in cytologic examination or for radioimmunodetection of regional and/or distant metastases of adenocarcinoma of the pancreas.     

Monoclonal antibody NIM-R2 shows differential reactivity with virgin and memory B cells

The differential reactivity of virgin and memory B cells with a monoclonal rat antibody (NIM-R2) has been established by inhibition experiments and cell separations using the fluorescence-activated cell sorter. B cells which stained strongly with NIM-R2 gave excellent primary responses in vitro but were unable to transfer substantial memory responses, whereas the weakest staining B cells gave excellent secondary but poor primary responses. NIM-R2 inhibited all primary responses in vitro which were examined, but failed to affect secondary responses.     

Immunohistochemical comparison between GCDFP-15 and estrogen and progesterone receptors in the diagnosis of metastatic carcinoma of the breast

Background: in the workup of tumors of unknown primary origin in women, a frequent consideration is breast carcinoma, because it is common and may initially present as metastasis. Objective: describe and compare the immunohistochemical profile of hormonal receptors (estrogen receptor and progesterone receptor) and GCDFP-15 in lymph node metastatic breast carcinoma according the histological grade. Methods: retrospective study analyzing 30 patients with identified primary breast cancer and lymph node metastasis. The cases were divided in three groups: grade I (well differentiated), grade II (moderately differentiated) and grade III (poorly differentiated). We used three antibodies (estrogen receptor, progesterone receptor and GCDFP-15) in the lymph node and compare the expression according the histological grade. Results: in metastatic lymph node from grade I breast carcinomas the hormone receptors were 100% positive and GCDFP-15 was 80% positive. In grade II, estrogen receptor and progesterone receptor were positive in 90 and 40% respectively, and GCDFP-15 was positive in 80%. In grade III, estrogen receptor and progesterone receptor were positive in 30 and 50% respectively, and GCDFP-15 in 60%. Conclusions: the immunohistochemical expression of hormonal receptors and GCDFP-15 in metastatic breast carcinoma is related to histological grade in the breast.     

Use of monoclonal antibody B72.3 as a marker of metastatic carcinoma cells in neoplastic effusions

The value of monoclonal antibody B72.3 as a diagnostic discriminator between mesothelioma and carcinoma cells in malignant effusions was assessed using the ABC method in a series of cell blocks prepared from centrifuged fluids. These were obtained from either pleural or peritoneal neoplastic effusions in patients with histologically verified malignant mesothelioma (n:10) or carcinoma (n:20). Reactivity with MAb B72.3 in at least 10% or more of tumour cells was found in 16 (80%) out of 20 metastatic carcinoma, whereas 2 mesotheliomas displayed positive immunostaining in less than 5% and approximately 20% of the malignant cells respectively. Reactive mesothelial cells were consistently non-immunostained. These results suggest that B72.3 positivity in greater than 10% of tumour cells is certainly indicative, but not absolutely diagnostic, of a metastatic origin of malignant effusions.     

Immunohistochemistry with monoclonal antibody B72.3 as an adjunct in the cytologic diagnosis of pancreatic carcinoma

Due to the morbidity of open tissue biopsy, the cytologic diagnosis of pancreatic carcinoma by fine needle aspiration or examination of biliary tree fluid is highly desirable. Immunohistochemistry with monoclonal antibody B72.3 has been advocated as an adjunct in the identification of tumor cells in body fluids. To assess its usefulness as an adjunct in the diagnosis of pancreatic carcinoma, we examined cytologic specimens of the pancreas from 35 patients [24 pancreatic carcinoma, 6 metastases (4 adenocarcinoma and 1 each of Hodgkin's disease and melanoma), 5 with benign conditions] with an immunohistochemical procedure using B72.3 directly over the Papanicolaou-stained slides. Of the pancreatic carcinomas, 21 of 24 (87%) were cytologically positive and 21 of 24 (87%) marked with B72.3. With both techniques, 23 of 24 cases (96%) could be identified. Three of four metastatic adenocarcinomas were positive by both cytology and B72.3. No staining occurred in the metastatic melanoma, Hodgkin's disease, or 3 of 5 benign conditions. In two benign duodenal aspirates, an unusual reticular B72.3 staining occurred in the mucin of acinar and goblet cells which could be misinterpreted as positive staining. In our experience, B72.3 enhances the sensitivity of the cytologic diagnosis of pancreatic cancer. Unrecognized single tumor cells, cytologically uninterpretable cells, and tumor cell clusters that could be misinterpreted as reactive epithelium mark with B72.3. Care should be taken to avoid misinterpretation of nonspecific mucin staining with this antibody.     

Immunohistochemical reactivity of a monoclonal antibody prepared against human breast carcinoma

Summary The reactivity profile of an IgM monoclonal antibody, MBR1, raised against the human breast cancer cell line MCF7, was studied in a variety of human tumours and non-neoplastic tissues by light microscopic immunohistochemistry. The range of reactivity included specific types of non-neoplastic epithelial cells and a number of epithelial tumours. Most mammary carcinomas reacted with MBR1, but adenocarcinomas and squamous carcinomas from different sites were also strongly positive. Different patterns of immunoreactivity were apparent in microscopically normal tissues, in tissues with inflammatory changes and in carcinomas. Heterogeneous staining, despite morphological similarities, was documented in neoplastic and non-neoplastic epithelial cells. The reactivity of MBR1 was different from that reported for other monoclonal antibodies, but revealed similarities to that of monoclonal antibodies and polyclonal sera against human milk fat globule membrane.     

Expression of the PIP/GCDFP-15 gene and survival in breast cancer

Expression of the PIP/GCDFP-15 gene was determined by measuring PIP/GCDFP-15-mRNA in breast carcinomas of 91 patients. The patients were followed-up for an average of 47 months after initial diagnosis and treatment of the disease. There were no deaths in the group of 14 patients with tumours of high PIP/GCDFP-15-mRNA levels, while 16 of 77 patients of the group with low PIP/GCDFP-15-mRNA tumour levels died. A similar advantage for high PIP/GCDFP-mRNA expression was observed with regard to disease free survival.     

A comparison between Ki-67 antibody reactivity and other pathological variables in breast carcinoma.

Methods of assessing tumor proliferation rates include mitosis counting, flow cytometry and thymidine labelling. While the former is inaccurate and poorly reproducible, the latter methods are time consuming and expensive to perform. Ki-67 is a monoclonal mouse antibody which has been shown to react with a nuclear antigen in proliferating cells. Frozen sections from 75 specimens of breast carcinoma were immunostained with this antibody using an immunoperoxidase technique. The percentage of tumor cells stained, the Ki-67 score, was then compared with a number of pathological and clinical variables in the patients concerned. A positive correlation was seen between the Ki-67 score and mitotic rate (r = 0.71); and a negative correlation was seen between Ki-67 score and estrogen receptor status (r = -0.4). Ki-67 immunostaining may represent a cheap and reproducible method of assessing proliferation rates of breast carcinomas which is applicable in routine laboratories. Further prospective studies are being undertaken to assess its contribution to prognosis.     

Monoclonal antibody specific to virulence-associated 15- to 17-kilodalton antigens of Rhodococcus equi.

Virulent Rhodococcus equi produces 15- to 17-kDa surface protein antigens. These antigens are used as markers to identify virulent R. equi isolates from foals and their environment by Western blot (immunoblot) analysis with naturally infected foal serum. In the present study, a monoclonal antibody (MAb; 10G5) was generated against the 15- to 17-kDa antigens excised from sodium dodecyl sulfate-polyacrylamide gels to develop sensitive and specific immunoblot assays for the identification of virulent R. equi. MAb 10G5 strongly reacted with R. equi ATCC 33701 and L1, which expressed 15- to 17-kDa antigens by Western blot, colony blot, and dot immunobinding assays, but it did not react with strains ATCC 33701P- and L1P-, which lacked the antigens. For identification of virulent R. equi, clinical and environmental isolates were tested by these assays with the MAb, and all virulent strains were successfully identified; these strains possessed virulence plasmids. These results suggest that the MAb is a useful reagent for the identification of virulent R. equi.     

PIP/GCDFP-15 gene expression and apocrine differentiation in carcinomas of the breast

The frequency and the significance of apocrine differentiation in carcinomas of the breast are uncertain, because of the lack of reliable and reproducible criteria for morphological diagnosis. The 15 kDa glycoprotein of cystic breast disease (GCDFP-15) is regarded as a specific functional marker of apocrine cells. Expression of the prolactin-inducible protein (PIP)/GCDFP-15 gene was investigated by Northern blot analysis and in situ hybridization in breast cancer cell lines and in an unselected series (33 cases) of primary carcinomas of the breast. On the same cases, histological assessment of apocrine differentiation and immunocytochemical detection of GCDFP-15 were also performed and correlated with follow-up data. The presence of PIP/GCDFP-15 mRNA was a feature of a relatively high number of cases, but was incompletely correlated with histological and immunocytochemical evidences of apocrine differentiation. Expression of the PIP/GCDFP-15 gene was significantly associated with relapse-free survival, and may represent a novel variable of functional and prognostic relevance.Work supported by grants from Associazione Italiana per la Ricerca ca sul Cancro (AIRC) (Milan, Italy), Consiglio Nazionale Ricerche (CNR, grant N. 93.02125.PF39), Ministero dell' Universita' e della Ricerca Scientifica e Tecnologica (MURST), Rome, Italy.     

Expression of MUC2 epithelial mucin in breast carcinoma.

AIMS--To examine the expression of the MUC2 epithelial mucin in breast carcinoma; to relate this to patient survival. METHODS--Sections from 210 breast carcinomas were stained with the anti-MUC2 core protein monoclonal antibody, 4F1, using an immunoperoxidase technique. The proportion of tumour cells positively stained and the localisation and intensity of any staining were recorded. Expression of MUC2 was compared with histological type and grade, tumour size, presence of nodal metastases, presence of oestrogen receptors, and menopausal status. The prognostic value of MUC2 expression was examined using Kaplan-Meier survival analysis. RESULTS--MUC2 mucin was detected in 19% of cases of invasive carcinoma, in 11% of cases of carcinoma in situ, where present, but very rarely in adjacent normal breast epithelium. Presence of MUC2 was significantly associated with a shorter disease free interval (p < 0.05), although the observed difference in duration of overall survival was not significant. CONCLUSIONS--The MUC2 detected in breast carcinoma may be underglycosylated or staining may represent detection of the protein core before the completion of glycosylation. The virtual absence of 4F1 reactivity in normal breast epithelium suggests that, unlike the MUC1 mucin, the MUC2 mucin is not highly expressed by these cells. The mechanism by which expression of MUC2 affects the biology of breast tumours is unclear, although expression may be a reflection of general derepression of genes during tumour progression.     

The ultrastructural localization of gross cystic disease fluid protein (GCDFP-15) in breast epithelium.

GCDFP-15 is a major constituent protein of 15,000-dalton monomer size present in breast gross cystic disease fluid. Immunoperoxidase staining of GCDFP-15 has shown the protein to be present in normal apocrine epithelium, metaplastic apocrine epithelium of the breast, and breast carcinomas with apocrine features. To delineate ultrastructurally the localization of GCDFP-15 in benign breast epithelium, a low-temperature embedding colloidal gold technique was used. Metaplastic apocrine epithelium of the breast showed GCDFP-15 to be localized in Golgi vesicles and cytoplasmic granules. At the cell apices these granules were contained in vacuoles and appeared to be released by exocytosis. There was labeling of cyst fluid within microcyst lumens. This report is the first to ultrastructurally characterize this protein and its mode of secretion.     

Proliferative index in breast carcinoma determined in situ by Ki67 immunostaining and its relationship to clinical and pathological variables

Sixty cases of primary breast carcinoma have been studied using a monoclonal antibody, Ki67, which recognizes an antigen expressed by cells in G1, S, G2, and M phases of the cell cycle but not Go. A Ki67 score (positive cells/total tumour cells) was determined, and possible relationships between this index of cellular proliferation and a number of clinical and pathological parameters were investigated. There was a strong positive correlation between the Ki67 score and mitotic index (p less than 0.001), a weak negative correlation with age (p less than 0.02), and weak positive correlations with histological tumour grade (p less than 0.03), tumour necrosis (p less than 0.01), and cellular reaction (p less than 0.01). No relationship was noted between the Ki67 score and tumour size, nodal status, tumour oestrogen receptor levels, or menopausal status. The Ki67 score may prove to be an objective indicator of biological behaviour and thus be of clinical significance, particularly since it is not strongly related to other clinical and pathological parameters used in predicting outcome in breast carcinoma.