Localization of mucinous-like carcinoma associated antigen (MCA) in breast pathology: comparison with carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA)

The topographic distribution of a mucinous-like cancer antigen (MCA) recognized by a monoclonal antibody b-12 (MAb b-12) was assessed in benign (38) and malignant (66) breast tissues. The reactivity of MAb b-12 showed a good selectivity for breast tissues, reacting both with normal tissues and breast cancer. The degree of MCA expression was evaluated in the various groups of breast pathology adopting quantitative criteria of assessment. With the criteria of evaluation adopted, strong staining was observed in 71.4% breast carcinomas. The most positive reaction was demonstrated in mucinous carcinoma. MCA distribution in breast tissue was compared with the distribution of two other antigens, CEA and TPA. Reactivity of MAb b-12 was higher than the reactivity shown by the anti-CEA and anti-TPA antibodies.     

Modalities of synthesis of Ki67 antigen during the stimulation of lymphocytes

The antibody Ki67 is currently used to evaluate the proliferative fraction of solid tumors and some hematological malignancies. We have used phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes as a model to study the entry of quiescent cells into cell cycle and to follow their progress to the next cycle. Flow cytometric analysis of lymphocyte samples stained with the antibody Ki67 and a DNA marker has allowed us to follow the expression of Ki67 antigen (Ki67 Ag) as a function of the position of the cells in the cell cycle. The use of drugs blocking the stimulated lymphocytes in different phases of the cell cycle permitted us to demonstrate that Ki67 Ag expression started from the beginning of the first S phase. The level of Ki67 Ag increased during S phase until mitosis, when its expression was maximal. After division, the cells in G1 phase showed a decrease in Ki67 Ag expression (possibly corresponding to degradation) until they reentered S phase, when the level of Ki67 Ag increased again. The results confirm that the expression of Ki67 Ag is related to the proliferative state of the cells and suggest that it may be used to determine the proliferative cell fraction in hematopoietic tissues.     

Applications of monoclonal antibodies in clinical cytology as exemplified by studies with monoclonal antibody B72.3. The George N. Papanicolaou award lecture

The monoclonal antibody (MAb) B72.3, reactive with a high-molecular-weight, glycoprotein, tumor-associated antigen, designated TAG-72, has been previously shown to be reactive with formalin-fixed, paraffin-embedded tissue sections of adenocarcinomas of the ovary, colon and breast, but not a variety of normal adult tissues. It has demonstrated utility as an immunocytochemical adjunct for the diagnosis of carcinoma in cell blocks and cytocentrifuge preparations of human serous effusions, with selective reactivity for tumor cells (particularly adenocarcinoma) over reactive mesothelium. Using the avidin-biotin complex (ABC) method of immunoperoxidase staining and formalin-fixed, paraffin-embedded cell suspensions, MAb B72.3 detected tumor cells in effusions from all of 21 patients with adenocarcinoma of the breast. No reactivity was demonstrated in any cell type in benign effusions from 41 patients. In contrast, MAb B72.3 showed no reactivity to leukemic or lymphomatous effusions, or to mesothelial cells from malignant effusions. MAb B72.3 also detected adenocarcinoma cells in effusion specimens from 12 of 12 patients with adenocarcinoma of the lung and 16 of 16 patients with adenocarcinoma of the ovary. MAb B72.3 has recently been used with fine needle aspiration (FNA) biopsy specimens and the corresponding surgically excised tumors to determine cellular reactivity. Using the ABC immunoperoxidase method, fine needle aspirates and corresponding surgically excised tumors were analyzed for TAG-72 expression. Positive staining with MAb B72.3 was observed in needle aspirates of 27 of 27 adenocarcinomas and adenosquamous carcinomas of the lung, 17 of 21 adenocarcinomas of the breast, 6 of 6 adenocarcinomas of the colon and in carcinomas from other body sites. In contrast, 21 small-cell carcinomas of the lung, 13 malignant melanomas, 2 lymphomas and 2 sarcomas did not stain with the antibody. Benign lesions from the breast, lung, pancreas, parotid and thyroid also showed no staining. In many patients, tumor-bearing tissue had also been resected and was available for comparative examination with MAb B72.3. In more than 90% of these patients, the staining patterns of the tumor cells in the aspirates were found to be predictive of the patterns of antibody reactivity in the comparable surgically resected tumors. From these studies, it is concluded that MAb B72.3 defines a tumor-associated antigen that is expressed in neoplastic cells versus benign cells, that is most selectively expressed in carcinomas and that may be used as a novel adjunct for the diagnosis of neoplasms in effusions and in fine needle aspiration biopsies.     

Demonstration of mucinous-like carcinoma-associated antigen in bone marrow and lymph node biopsies from patients with breast carcinoma.

Two hundred and fifty bone marrow and 140 lymph nodal biopsies were analyzed immunocytochemically, using a mouse monoclonal antibody b-12 (M Ab b-12), which reacts with MCA (mucinous-like carcinoma-associated antigen). The presence of MCA in bone marrow specimens was demonstrated in 102 out of 105 (97.1%) breast cancer metastases, 5 out of 8 (62.5%) gastric cancers, 5 out of 6 (83.3%) colon cancers, 3 out of 5 (60%) prostate cancers, 11 out of 26 (42.3%) lung cancers and 25 out of 30 (83.3%) unknown primary cancers, while no positivity to anti-MCA antibody was found in 30 cases of normal bone marrow biopsies, 5 cases of non epithelial malignancies and 30 cases of hemolymphoproliferative disease. Normal lymph nodes and non-epithelial lymph node metastases did not show any reaction to M Ab b-12; on the contrary MCA positive staining was observed in 75 out of 75 (100%) lymph nodal metastases in breast cancer. These results suggest that application of M Ab b-12 in immunohistochemistry is valid for the detection of bone marrow and lymph nodal micrometastases of epithelial origin.     

Image cytometry of aneuploidy, growth fraction (MoAb Ki-67) and hormone receptors (ER, PR) immunocytochemical assays in breast carcinomas

DNA nuclear content was assessed in human breast carcinomas (n = 132) using image cytometry. Optical density histograms of Feulgen stained cell imprints from fresh tissue samples, subsequently frozen for immunocytochemical assays, were determined by the SAMBA system and used for the DNA index, the ploidy balance (PB) and the proliferation index (PI) computation. The three parameters were correlated to (i) histological data (tumour grade, vascular and/or lymph node invasion) and to (ii) growth fraction (Ki67), hormone receptor antigenic sites (ER, PR) and intramedullar (bone marrow) biopsies and anti-KL1-positive epithelial cells. It was shown that 57% of breast carcinomas were aneuploid. Aneuploidy PI significantly correlated to the criteria of poor prognosis such as high tumour grade, vascular and lymphatic invasion and to increased Ki67-positive cells, and the absence of or low ER and PR. Since image cytometry is easy to handle and perfectly suitable for current diagnostic practice in pathology departments, particularly for tumour cell ploidy assessment and standardized analysis of immunostaining procedures with morphological control of the preparation, we conclude that image cytometry, as performed with the SAMBA, must be regarded as a relevant tool for prognosis evaluation and therapy guidance in individual patients.     

Expression of a melanoma-tumor-associated antigen as demonstrated by a monoclonal antibody (D6.1) in cytopathologic preparations of human tumor cells from effusions and needle aspirates

Immunocytopathologic studies were performed on 79 fine needle aspiration biopsies (FNABs) and effusions from 13 melanomas and 57 other human neoplasms with the monoclonal antibody (MAb) D6.1 raised against a partially purified melanoma-tumor-associated antigen (MTAA). The purposes of these studies were (1) to evaluate the ability of MAb 6.1 to react with melanoma cells in cytopathologic preparations and (2) to define the spectrum of reactivity of MAb D6.1 in cytopathologic preparations of non-melanomas. Cytocentrifuge preparations of the cytopathologic specimens were permitted to react with the primary antibody and were then stained by the avidin-biotin-immunoperoxidase method. Thirteen of 13 FNABs of malignant melanomas exhibited staining reactivity with MAb D6.1. Among the nonmelanoma tumors tested, staining reactivity was observed in 30 of 57 specimens. Among specific neoplasms, staining was present in 5 of 11 adenocarcinomas of the breast, 2 of 7 ovarian adenocarcinomas and 5 of 6 metastatic adenocarcinomas from the colon. Among 17 lung cancers examined, staining was noted in 4 of 7 adenocarcinomas, 3 of 4 large-cell undifferentiated carcinomas and 2 of 3 poorly differentiated squamous-cell carcinomas. Two small-cell undifferentiated carcinomas and one carcinoid failed to stain. Three of three adenocarcinomas of the pancreas showed staining. Among the remaining neoplasms examined, one specimen each of carcinoma of the prostate and the cervix and one carcinoma of undetermined primary exhibited staining. Two malignant lymphomas did not stain. Staining of mesothelial cells was observed in three of nine benign effusions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth fraction of colorectal carcinoma (Ki67): a comparative study.

We studied the growth fraction of 55 resected colorectal adenocarcinomas by means of a three-step immunoperoxidase technique (avidin-biotin-peroxidase) using the monoclonal antibody Ki67 directed against a cell proliferation-associated nuclear antigen. The percentage of Ki67-positive cells was evaluated independently by two observers, and a Ki67 score was obtained for each case. No correlation was observed between Ki67 staining and patient's age and sex, tumor size and localization or grading and staging according to Dukes' method (modified by Astler-Coller and Turnbull). The growth fraction showed extreme heterogeneity in the cases examined, within each grade of differentiation.     

A sequential double immunoenzymic staining procedure to obtain cell kinetic information in normal and hyperproliferative epidermis

Summary A sequential double immunoenzymic staining procedure was developed using the monoclonal antibody anti-BrdUrd and Ki67 in order to determine whether hyperproliferative skin disorders, such as psoriasis, are characterized by an increased growth fraction rather than a much shorter cell cycle time of all germinative cells. Ki67 binds to a proliferation-associated nuclear antigen in a variety of human cell types, and anti-BrdUrd can be used to identify DNA-synthesizing cells. Although in hyperproliferative epidermis the absolute numbers of BrdUrd-positive cells as well as Ki67-positive cells were grossly increased, the ratio of these values was not changed compared to the ratio found in the epidermis of the clinically uninvolved skin of psoriatic patients and in normal epidermis. This suggests an increased growth fraction in hyperproliferative epidermis.Our data show that immunohistochemical double-staining techniques can be a valuable tool in the study of cell cycle kinetics in epithelial tissues.     

Measurement of markers for breast cancer in a model system using laser scanning cytometry

BACKGROUND: A variety of markers, including Ki67, estrogen receptors (ER), and progesterone receptors (PgR), are frequently measured in fine needle aspirates (FNA) from human breast carcinomas. We used a human breast carcinoma cell line, MCF7, as a model system to investigate the use of laser scanning cytometry (LSC) for the measurement of these markers. Additionally, we measured the number of apoptotic cells. METHODS: Cells were treated with drugs to vary the expression of markers and the number of apoptotic cells. They were then fixed on microscope slides. For LSC, the cells were stained for the different markers with fluorescein using immunofluorescence and for apoptotic cells using the TUNEL assay. The nuclei were counterstained with propidium iodide. A parallel set of slides was stained using horseradish peroxidase and diaminobenzidine and scored manually by conventional light microscopy. RESULTS: The results from the LSC closely paralleled those obtained by manual scoring of immunohistochemical stains. CONCLUSIONS: It should be possible to use LSC for the routine measurement of nuclear markers in FNAs from human breast carcinomas.     

Identification of novel tumor antigens with patient-derived immune-selected antibodies

The identification of tumor antigens capable of eliciting an immune response in vivo may be an effective method to identify therapeutic cancer targets. We have developed a method to identify such antigens using frozen tumor-draining lymph node samples from breast cancer patients. Immune responses in tumor-draining lymph nodes were identified by immunostaining lymph node sections for B-cell markers (CD20&CD23) and Ki67 which revealed cell proliferation in germinal center zones. Antigen-dependent somatic hypermutation (SH) and clonal expansion (CE) were present in heavy chain variable (VH) domain cDNA clones obtained from these germinal centers, but not from Ki67 negative germinal centers. Recombinant VH single-domain antibodies were used to screen tumor proteins and affinity select potential tumor antigens. Neuroplastin (NPTN) was identified as a candidate breast tumor antigen using proteomic identification of affinity selected tumor proteins with a recombinant VH single chain antibody. NPTN was found to be highly expressed in approximately 20% of invasive breast carcinomas and 50% of breast carcinomas with distal metastasis using a breast cancer tissue array. Additionally, NPTN over-expression in a breast cancer cell line resulted in a significant increase in tumor growth and angiogenesis in vivo which was related to increased VEGF production in the transfected cells. These results validate NPTN as a tumor-associated antigen which could promote breast tumor growth and metastasis if aberrantly expressed. These studies also demonstrate that humoral immune responses in tumor-draining lymph nodes can provide antibody reagents useful in identifying tumor antigens with applications for biomarker screening, diagnostics and therapeutic interventions.     

Thymidine kinase-1/CD31 double immunostaining for identifying activated tumor vessels

Although angiogenesis plays a crucial role in cancer growth and progression, no reliable method for assessing angiogenesis in tumor tissue sections currently is available. Using biomarkers with high specificity for proliferating endothelial cells could help quantify angiogenic activity. Thymidine kinase-1 (TK1) is an enzyme involved in the salvage pathway of DNA synthesis and its activity is correlated with cell proliferation. We investigated the use of double immunostaining for TK1 and CD31 for identifying activated tumor vessels. Differences in TK1/CD31 positive vessel rates (PVRs) between tumor and adjacent normal tissues were evaluated in 39 colorectal carcinoma (CRC) samples and compared with those of Ki67/CD31 double stained tissues. Mean TK1/CD31 PVR (23.6%) in CRCs was 13.9 fold greater than in adjacent normal tissues (1.7%)). By comparison, mean Ki67/CD31 PVR in CRCs was 20.0%, i.e. only 4.8 fold greater than in normal tissues (4.2%). Also, mean TK1/CD31 PVR in normal tissues was significantly less than mean Ki67/CD31 PVR. Our findings indicate that double immunostaining for TK1/CD31 can detect activated tumor vessels more accurately than staining for Ki67/CD31 and potentially could identify tumors that will respond to anti-angiogenic therapy.     

Immunocytochemical analysis of cytocentrifuged fine needle aspirates. A study based on lung tumors aspirated in vitro

The value of Cytospin preparations of fine needle aspiration (FNA) biopsy material for immunocytochemical analysis was investigated using aspirates obtained from 23 resected human lung tumors. The results were compared with those on cryostat sections from the same tumors. The Cytospin preparations of the FNA biopsies gave the best immunostaining reactions and enabled a comprehensive range of monoclonal antibodies (MAbs) to be utilized. The quality of the Cytospin immunostaining compared favorably with that on cryostat sections of the same tumors and generally yielded a similar immunophenotype. However, the Cytospin preparations were not suitable for staining with MAb Ki67, which detects an antigen associated with cellular proliferation. With Ki67, conventionally prepared smears were much superior and enabled an assessment of tumor growth fraction that concurred with the growth fraction calculated from cryostat sections in most cases.     

The use of monoclonal antibody B72.3 in the management of gynecologic malignancies

Monoclonal antibodies are currently used in the diagnosis of gynecologic malignancies by way of immunohistochemical assays, serum assays, and in situ radiolocalization of carcinoma lesions. Among them is MAb B72.3, generated against a human tumor-associated antigen (TAG-72). Using immunohistochemical techniques, MAb B72.3 has shown reactivity with 100 percent of common epithelial ovarian carcinomas and endometrial carcinomas and non-reactivity with normal adult tissues, with the exception of normal secretory endometrium. B72.3 appears to be a valuable immunocytologic adjunct, with greater than 90 percent of effusions and fine-needle aspiration biopsies from gynecologic carcinomas showing reactivity. Using a serum assay developed to detect the presence of the TAG-72 antigen, 48 percent of patients with ovarian carcinoma demonstrated TAG-72-positive sera versus 1 percent of control sera. 131I-labeled MAb B72.3 IgG and gamma scanning have been used for the in situ detection of metastatic carcinoma. Twelve of 15 patients with ovarian carcinoma showed positive gamma scans, and approximately 80 percent of the lesions demonstrated specific localization of the antibody. These studies indicate the potential utility of MAb B72.3 in the diagnosis of gynecologic carcinoma.     

Identification of a family of high molecular weight tumor-associated glycoproteins

The monoclonal antibody (MAb) designated DF3 was prepared against a human breast carcinoma metastatic to liver. This MAb reacts with a high molecular weight glycoprotein detectable in human breast carcinomas and human milk. In contrast, MAb F36/22 was prepared against the MCF-7 breast carcinoma cell line, MAb 115-D8 against human milk fat globule membrane (HMFGM) and MAb Ca1 against the HEp-2 human laryngeal carcinoma cell line. These MAb have similar patterns of reactivity with normal tissues and tumors based upon immunoperoxidase staining. In the present study we have monitored reactivity of these MAb against DF3 antigen purified from human breast carcinoma cell lines (MCF-7, BT-20) and HMFGM. Solid phase immunoassays and immunoblotting demonstrate that MAb DF3, F36/22, 115-D8, and Ca1 all react with the same purified DF3 antigen. Furthermore, immunoblot analysis indicates that the DF3 antigen reactive with these MAb differs structurally in preparations from breast carcinoma cells and HMFGM. We also demonstrate that MAb F36/22 completely inhibits MAb DF3 binding in competitive blocking assays. In contrast, the results indicate that MAb 115-D8 and Ca1 only partially block MAb DF3 reactivity and the extent of this inhibition varies with DF3 antigen purified from breast carcinoma cells and HMFGM. Taken together, these findings with multiple MAb prepared against a variety of immunogens suggest that existence of a family of related but not identical high molecular weight tumor-associated glycoproteins.     

Expression of p53, p21/waf, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas

This study investigated the combined immunoexpression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in colorectal adenocarcinomas and correlated expression patterns with tumour stage and grade. Paraffin sections from 98 cases of colorectal adenocarcinomas were stained by immunohistochemistry for p53, p21, bcl-2, bax, Rb and MIB-1 (Ki67) proteins. In addition, 12 cases of colorectal adenomas and normal colorectal mucosa were studied in parallel. P53, p21, bcl-2, bax, Rb and Ki67 proteins were detected in at least 5% of tumour cells in 63/98, 72/98, 52/98, 96/98 and 98/98 adenocarcinomas, respectively. Comparative study of the normal-adenoma-carcinoma tissues revealed abrogation of the normal immunotopography in adenomas and adenocarcinomas, and considerable modifications, increase or reduction, of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in adenocarcinomas when compared with normal mucosa and adenomas. Statistically significant correlations were found between low bax expression and Dukes C stage of carcinomas, Ki67 expression and carcinoma grade, and Ki67 and Rb expression. P53, p21, bcl-2 and Rb immunoexpression did not correlate with tumour stage or grade. Our findings show that low bax immunoexpression is frequently related to colorectal adenocarcinomas with lymph node metastases suggesting that low levels of bax expression play a role in late stage colorectal cancer. The correlation between Ki67 and Rb expression, in view of previous data that the hyperphosphorylated inactive Rb protein is frequently increased in colorectal adenocarcinomas, suggests that Rb protein is somewhat ineffective in inhibiting the cell-cycle progression in these malignancies. Furthermore, our findings provide immunohistochemical evidence that the abrogation of the normal immunotopography and the modifications of the expression of p53, p21, bcl-2, bax, Rb and Ki67 proteins reflect important events in colorectal oncogenesis.     

LN-6: a monoclonal antibody to vimentin expressed in non-hematopoietic mesenchymal cells and derived tumors and reactive in B5-fixed, paraffin-embedded tissues

We generated a monoclonal antibody (MAb), designated LN-6, directed against human vimentin, which retains its immunoreactivity in B5-fixed, paraffin-embedded tissues. Like other anti-vimentin MAb, LN-6 was found to be reactive with a wide spectrum of human sarcomas and normal cells of mesenchymal derivation. However, unlike other similar reagents, LN-6 was unreactive with normal and malignant human lymphoid cells and therefore displays a more restricted immunoreactivity. Because of its ability to stain routinely processed pathological tissues and its marked reactivity with human sarcomas, LN-6 is a unique reagent for the immunohistochemical diagnosis of human cancer.     

Immunocytochemical detection of Ki‐67 in Diff‐Quik‐stained cytological smears of canine mammary gland tumours

U.S. Choi and D.Y. Kim Immunocytochemical detection of Ki‐67 in Diff‐Quik‐stained cytological smears of canine mammary gland tumours Objective: To investigate whether Diff‐Quik stained fine needle aspirate smears can be used to evaluate Ki‐67 expression by immunocytochemistry. Methods: Both cytological and histological samples were obtained from 24 dogs with spontaneously developed mammary gland tumours. The cytological and histological specimens were examined by Diff‐Quik and H&E stains, respectively. After examination, both samples were immunostained using the same Ki‐67 antibody. The % Ki‐67 values were calculated based on the percentage of positively stained tumour cells per 500 and 1000 tumour cells in cytology and histology specimens, respectively. Results: Ki‐67 staining was successful in 17/24 smears (71%) and 19/23 sections (83%). The correlation coefficient between the percentage of Ki‐67‐positive cells in cytological smears and in the histological sections was 0.677 (P < 0.01). These values were significantly different between histologically benign and malignant tumour groups both in cytology and histology samples (P < 0.001). The threshold value of the percentage of Ki‐67‐positive cells for distinguishing benign from malignant tumours was set at 4.85% with 90.9% sensitivity and 92.3% specificity by Receiver Operating Characteristic (ROC) curve using histopathology as the gold standard. Conclusion: Diff‐Quik‐stained cytology smears can be used to detect the presence of Ki‐67 antigen when histology sections are not available.     

Human equilibrative nucleoside transporter 1 and carcinoma of the ampulla of Vater: expression differences in tumour histotypes

The human equilibrative nucleoside transporter 1 (hENT1) is the major means by which gemcitabine enters human cells; recent evidence exists that hENT1 is expressed in carcinoma of the ampulla of Vater and that it should be considered as a molecular prognostic marker for patients with resected ampullary cancer. Aim of the present study is to evaluate the variations of hENT1 expression in ampullary carcinomas and to correlate such variations with histological subtypes and clinicopathological parameters. Forty-one ampullary carcinomas were histologically classified into intestinal, pancreaticobiliary and unusual types. hENT1 and Ki67 expression were evaluated by immunohistochemistry, and apoptotic cells were identified by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate biotin nick end labelling (TUNEL) method. hENT1 overexpression was detected in 63.4% ampullary carcinomas. A significant difference in terms of hENT1 and Ki67 expression was found between intestinal vs. pancreaticobiliary types (P=0.03 and P=0.009 respectively). Moreover, a significant statistical positive correlation was found between apoptotic and proliferative Index (P=0.036), while no significant correlation was found between hENT1 and apoptosis. Our results on hENT1 expression suggest that classification of ampullary carcinoma by morphological subtypes may represent an additional tool in prospective clinical trials aimed at examining treatment efficacy; in addition, data obtained from Ki67 and TUNEL suggest a key role of hENT1 in tumour growth of ampullary carcinoma.Key words: human equilibrative nucleoside transporter 1, histotypes, vater ampulla, cancer, immunohistochemistry.     

Lewis y antigen is expressed in oral squamous cell carcinoma cell lines and tissues, but disappears in the invasive regions leading to the enhanced malignant properties irrespective of sialyl-Lewis x

Expression and implication of carbohydrate antigens in squamous cell carcinomas (SCCs) in oral cavity was examined. In the cell lines, type 2H and Lewis y antigens were markedly expressed. In the tissues from SCC patients and benign disorders, type 2H was highly expressed in hyperplasia (96.4 %), displasia (92.9 %) and SCC (100 %). Lewis y was, in turn, expressed mainly in cancer tissues (91.3 %), suggesting that Lewis y is a cancer-associated antigen. Normal oral mucosa showed no expression of these blood group antigens. Surprisingly, Lewis y antigen disappeared in the invasion sites where Ki-67 was definitely stained. Over-expression of Lewis y with manipulation of a fucosyltransferase cDNA resulted in suppression of cell growth and invasion, and knockdown of Lewis y also brought about increased cell growth and invasion. In either situations, no changes in the expression of sialyl-Lewis x could be found. Lowered tumor growth and invasion into surrounding tissues were also shown in Lewis y-positive SCC grafts in nu/nu mice. All these results together with alternative staining between Lewis y and Ki-67 in cancer tissues and FUT1 transfectants suggested that loss of Lewis y is a crucial event for the late stage of SCCs.     

An antibody raised against in vitro-derived human mast cells identifies mature mast cells and a population of cells that are Fc epsilon RI(+), tryptase(-), and chymase(-) in a variety of human tissues.

Selective markers for human mast cells are of paramount importance for understanding their role in physiological and pathological processes. A mouse monoclonal antibody (MAb) designated 2C7, raised against in vitro-derived human mast cells, was used in immunoenzymatic analysis of sections from a variety of human organs. Double immunolabeling with 2C7 and tryptase, chymase, Fc epsilon RIalpha, and c-kit was performed on cryostat tissue sections from skin, colon, uterus, breast, stomach, bladder, and lung. MAb 2C7 stained greater than 93% of the tryptase(+) or chymase(+) mast cells in all tissues examined. In addition, the majority of cells stained with the tryptase or chymase also stained for Fc epsilon RIalpha. However, there were a significant number of Fc epsilon RIalpha(1) cells in all tissues studied that were tryptase(-) and/or chymase(-). In contrast, MAb 2C7 in double immunoenzymatic staining co-localized with 93-96% of the Fc epsilon RIalpha(1) cells in all tissues. Analysis for c-kit expression on the different tissues revealed that the majority of tryptase(+) or chymase(+) cells in skin, uterus, bladder, and lung stained with c-kit. However, only approximately 70-78% of tryptase(+) cells in colon and stomach were c-kit(+). These data suggest that MAb 2C7 appears to identify mature mast cells and a population of Fc epsilon RIalpha(1), chymase(-), and tryptase(-) cells in a variety of human tissues.