Comparative immunohistochemical study of MUC1 and carbohydrate antigens in breast benign disease and normal mammary gland

An Introduction to the Relationship Between Lewis x and Malignancy Mainly Related to Breast Cancer and Head Neck Squamous Cell Carcinoma (HNSCC)

Lewis x functions as an adhesion molecule in glycolipids and glycoproteins since it mediates homophilic and heterophilic attachment of normal and tumoral cells. During malignancy, altered glycosylation is a frequent event; accumulating data support the expression of Lewis x in tumors although controversial results have been described including its relationship with patient survival. This report has been developed as an introduction to the relationship between Lewis x expression and breast cancer and head and neck squamous cell carcinoma (HNSCC). Results obtained in our laboratory are presented in the context of the literature.

Breast cancer cutaneous metastases are associated to uMUC1 and sialyl Lewis x and to highly malignant primary tumors

Breast cancer spreading to different organs have been related to different molecules and mechanisms, but cutaneous metastasis remains unexplored. Increasing evidence showed that MUC1 and some of its carbohydrate associated antigens may be implicated in breast cancer metastasis. In this study we analyzed these tumor markers in order to identify breast cancer cutaneous metastatic profiles. A cohort of 26 primary tumors from breast cancer patients with cutaneous metastases were included; also, cutaneous and lymphatic node metastatic samples and primary tumors from breast cancer patients without metastases were analysed. Immunohistochemical (IHC) studies demonstrated that both underglycosylated MUC1 (uMUC1) and sialyl Lewis x (sLex) to be positively associated with cutaneous metastatic primary tumors (p < 0.05). Notably, a high percentage of tumors with cutaneous metastases were characterized as triple negative and Her2+ tumors (37.5 % and 29 %, respectively). Some discordant results were found between primary tumors and their matched cutaneous metastases. To determine if MUC1 variants may be carriers of carbohydrate antigens, subcellular fractions from a cutaneous metastatic lesion were obtained, immunoprecipitated and analyzed by Western blot. We found that the isolated uMUC1 with a molecular weight of>200 kDa was also the site for binding of anti-sLex MAb; in coincidence, a high correlation of positive IHC expression of both markers was observed. Our findings confirm that breast cancer cutaneous metastases were associated to highly malignant primary tumors and sustain the hypothesis that u-MUC1 and sLe x may drive breast cancer cutaneous metastases.

Distinguishing Truncated and Normal MUC1 Glycoform Targeting from Tn-MUC1-Specific CAR T Cells: Specificity Is the Key to Safety

Genetically modified T cells expressing chimeric antigen receptors (CARs) demonstrate potent clinical antitumor effects in a variety of blood cancers. However, clinical activity in solid tumors has been disappointing and toxicity has been a serious concern (Lamers et al., 2013; Morgan et al., 2010). We recently found that a CAR composed of a scFv antibody fragment specific for the Tn-glycoform of MUC1 had potent activity in preclinical models of blood cancer and adenocarcinoma (Posey et al., 2016).

CA27.29 as a tumour marker for risk evaluation and therapy monitoring in primary breast cancer patients

Several trials showed that tumour markers are associated with an impaired prognosis for breast cancer. Whether earlier treatment can improve the course of the disease remains controversial. The SUCCESS Trial compares FEC (500/100/500)-docetaxel (100) vs. FEC (500/100/500)-docetaxel/gemcitabine (75/2000) as well as 2 vs. 5 years of zoledronate in high-risk primary breast cancer patients. In 2669 patients, CA27.29 was measured before and after chemotherapy with the ST AIA-PACK CA27.29 reagent for the AIA-600II automated enzyme immunoassay (Tosoh Bioscience, Belgium). Values above 31 U/ml were considered positive. Of the patients, 7.6 % (n = 202, mean 19, range 3-410) and 19.1 % (n = 511, mean 21, range 3-331) had elevated marker levels before and after chemotherapy, respectively. Of the patients, 4.9 and 78 % showed elevated and low CA27.29, respectively, at both time points. After treatment, 35 % of the pre-therapy positive patients were negative, and 15 % of the initially negative patients became positive. The correlation between both time points was significant (p < 0.0001). No correlations among nodal status, grading, hormonal status, HER2 status and CA27.29 levels were found. However, tumour size (p = 0.02), older age (p < 0.001) and post-menopausal status (p = 0.006) were significantly associated with higher CA27.29 levels. Before treatment, the prevalence of elevated CA27.29 was equally distributed between both treatment arms, whereas after chemotherapy, 13.7 % of the patients in the FEC-doc arm showed an increased level vs. 25.4 % of the patients in the FEC-doc/gemcitabine arm (p < 0.0001). However, we could not show a significant association between the G-CSF application (yes vs. no) and CA27.29 status before/after chemotherapy (p = 0.75). These results indicate a close relationship between CA27.29 levels and tumour mass. Increased values after the completion of chemotherapy might be attributed to treatment effects and should be considered with caution.

Nuclear localization of MUC1 extracellular domain in breast, head and neck, and colon cancer

Background

The glycoprotein MUC1 is overexpressed and underglycosylated in cancer cells. MUC1 is translated as a single polypeptide that undergoes autocleavage into 2 subunits (the extracellular domain and the cytoplasmic tail), and forms a stable heterodimer at the apical membrane of normal epithelial cells. The MUC1 cytoplasmic tail localizes to the cytoplasm of transformed cells and is targeted to the nucleus.

Aims

To study the expression of the MUC1 extracellular subunit in cell nuclei of neoplastic breast, head and neck, and colon samples.

Materials and Methods

330 primary tumor samples were analyzed: 166 invasive breast carcinomas, 127 head and neck tumors, and 47 colon tumors; 10 benign breast disease (BBD) and 40 normal specimens were also included. A standard immunohistochemical method with antigen retrieval was performed. Nuclear fractions from tissue homogenates and breast cancer cell lines (ZR-75, MDA-MB-231, MCF7, and T47D) were obtained and analyzed by Western blotting (WB). The anti-MUC1 extracellular subunit monoclonal antibody HMFG1 was used for immunohistochemistry.

Results

37/166 breast cancer specimens, 5/127 head and neck cancer specimens, 2/47 colon cancer samples, and 3/10 BBD samples showed immunohistochemical staining at the nuclear level. No nuclear reaction was detected in normal samples. By WB, breast and colon cancer purified nuclear fractions showed reactivity at 200 kDa in 3/30 breast and 3/20 colon cancer samples as well as purified nuclear fractions obtained from breast cancer cell lines.

Conclusions

This study shows that the MUC1 extracellular domain might be translocated to the cell nucleus in breast, head and neck, and colon cancer as well as BBD.

Quantitative assessment of Tn antigen in breast tissue micro-arrays using CdSe aqueous quantum dots

In this study, we examined the use of CdSe aqueous quantum dots (AQDs) each conjugated to three streptavidin as a fluorescent label to image Tn antigen expression in various breast tissues via a sandwich staining procedure where the primary monoclonal anti-Tn antibody was bound to the Tn antigen on the tissue, a biotin-labeled secondary antibody was bound to the primary anti-Tn antibody, and finally the streptavidin-conjugated AQDs were bound to the biotin on the secondary antibody. We evaluated the AQD staining of Tn antigen on tissue microarrays consisting of 395 cores from 115 cases including three tumor cores and one normal-tissue core from each breast cancer case and three tumor cores from each benign case. The results indicated AQD-Tn staining was positive in more than 90% of the cells in the cancer cores but not the cells in the normal-tissue cores and the benign tumor cores. As a result, AQD-Tn staining exhibited 95% sensitivity and 90% specificity in differentiating breast cancer against normal breast tissues and benign breast conditions. These results were better than the 90% sensitivity and 80% specificity exhibited by the corresponding horse radish peroxidase (HRP) staining using the same antibodies on the same tissues and those of previous studies that used different fluorescent labels to image Tn antigen. In addition to sensitivity and specificity, the current AQD-Tn staining with a definitive threshold was quantitative.

MUCI positive cutaneous metastasis with transepidermal elimination from a breast carcinoma

Breast cancer is the most common cause of cutaneous metastases from internal malignancies. Generally, the neoplastic cells are located in the dermis or hypodermis, while a finding of transepidermal elimination on cutaneous metastases is exceptional. In this report we present a patient with perforating cutaneous metastases from breast cancer with mucin 1 expression. Cutaneous, bone, lung, and hepatic lesions were detected two years after the diagnosis of the primary tumor.

Assessing breast cancer margins ex vivo using aqueous quantum-dot-molecular probes

Positive margins have been a critical issue that hinders the success of breast- conserving surgery. The incidence of positive margins is estimated to range from 20% to as high as 60%. Currently, there is no effective intraoperative method for margin assessment. It would be desirable if there is a rapid and reliable breast cancer margin assessment tool in the operating room so that further surgery can be continued if necessary to reduce re-excision rate. In this study, we seek to develop a sensitive and specific molecular probe to help surgeons assess if the surgical margin is clean. The molecular probe consists of the unique aqueous quantum dots developed in our laboratory conjugated with antibodies specific to breast cancer markers such as Tn-antigen. Excised tumors from tumor-bearing nude mice were used to demonstrate the method. AQD-Tn mAb probe proved to be sensitive and specific to identify cancer area quantitatively without being affected by the heterogeneity of the tissue. The integrity of the surgical specimen was not affected by the AQD treatment. Furthermore, AQD-Tn mAb method could determine margin status within 30 minutes of tumor excision, indicating its potential as an accurate intraoperative margin assessment method.

Cancer vaccines and carbohydrate epitopes

Tumor-associated carbohydrate antigens (TACA) result from the aberrant glycosylation that is seen with transformation to a tumor cell. The carbohydrate antigens that have been found to be tumor-associated include the mucin related Tn, Sialyl Tn, and Thomsen-Friedenreich antigens, the blood group Lewis related Lewis(Y), Sialyl Lewis(X) and Sialyl Lewis(A), and Lewis(X) (also known as stage-specific embryonic antigen-1, SSEA-1), the glycosphingolipids Globo H and stage-specific embryonic antigen-3 (SSEA-3), the sialic acid containing glycosphingolipids, the gangliosides GD2, GD3, GM2, fucosyl GM1, and Neu5GcGM3, and polysialic acid. Recent developments have furthered our understanding of the T-independent type II response that is seen in response to carbohydrate antigens. The selection of a vaccine target antigen is based on not only the presence of the antigen in a variety of tumor tissues but also on the role this antigen plays in tumor growth and metastasis. These roles for TACAs are being elucidated. Newly acquired knowledge in understanding the T-independent immune response and in understanding the key roles that carbohydrates play in metastasis are being applied in attempts to develop an effective vaccine response to TACAs. The role of each of the above mentioned carbohydrate antigens in cancer growth and metastasis and vaccine attempts using these antigens will be described.

Transmembrane mucins as novel therapeutic targets

Membrane-tethered mucin glycoproteins are abundantly expressed at the apical surfaces of simple epithelia, where they play important roles in lubricating and protecting tissues from pathogens and enzymatic attack. Notable examples of these mucins are MUC1, MUC4 and MUC16 (also known as cancer antigen 125). In adenocarcinomas, apical mucin restriction is lost and overall expression is often highly increased. High-level mucin expression protects tumors from killing by the host immune system, as well as by chemotherapeutic agents, and affords protection from apoptosis. Mucin expression can increase as the result of gene duplication and/or in response to hormones, cytokines and growth factors prevalent in the tumor milieu. Rises in the normally low levels of mucin fragments in serum have been used as markers of disease, such as tumor burden, for many years. Currently, several approaches are being examined that target mucins for immunization or nanomedicine using mucin-specific antibodies.

Mucins in the pathogenesis of breast cancer: implications in diagnosis, prognosis and therapy

Mucins are high molecular weight, multifunctional glycoproteins comprised of two structural classes-the large transmembrane mucins and the gel-forming or secreted mucins. The primary function of mucins is to protect and lubricate the luminal surfaces of epithelium-lined ducts in the human body. Recent studies have identified a differential expression of both membrane bound (MUC1, MUC4 and MUC16) and secreted mucins (MUC2, MUC5AC, MUC5B and MUC6) in breast cancer tissues when compared with the non-neoplastic breast tissues. Functional studies have also uncovered many unique roles of mucins during the progression of breast cancer, which include modulation in proliferative, invasive and metastatic potential of tumor cells. Mucins function through many unique domains that can form complex association with various signaling molecules including growth factor receptors and intercellular adhesion molecules. While there is growing information about mucins in various malignancies including breast cancer, no focused review is there on the expression and functional roles of mucins in breast cancer. In this present review, we have discussed the differential expression and functional roles of mucins in breast cancer. The potential of mucins as diagnostic and prognostic markers and as therapeutic targets in breast cancer have also been discussed.

Invasive breast cancer in Argentine women: association between risk and prognostic factors with antigens of a peptidic and carbohydrate nature

OBJECTIVE

In breast cancer, several tumor markers have been identified. The marker most extensively associated with breast cancer is MUC1. The objective of the study was to analyze prognostic and risk factors in relation to tumor markers in order to clarify breast cancer biology. A total of 349 primary tumor samples and lymph nodes from breast cancer patients were studied. Risk and prognostic factors were considered. An immunohistochemical approach was applied and an extensive statistical analysis was performed, including frequency analysis and analysis of variance. Correlation among variables was performed with principal component analysis.

RESULTS

All the antigens showed an increased expression according to tumor size increment; moreover, sialyl Lewis x expression showed a significant increase in relation to disease stage, whereas Tn and TF presented a positive tendency. Vascular invasion was related to sialyl Lewis x expression and number of metastatic lymph nodes. Taking into account risk factors, when a patient had at least one child, Lewis antigens diminished their expression. In relation to breastfeeding, sialyl Lewis x expression diminished, although its apical expression increased.

CONCLUSION

Associations between MUC1 and carbohydrate antigens and risk and prognostic factors show the complexity of the cellular biological behavior that these antigens modulate in breast cancer.

Immunohistochemical evidence of Muc1 expression during rat embryonic development

During embryonic development, studies on mouse and human embryos have established that Muc1/MUC1 expression coincides with the onset of epithelial sheet and glandular formation. This study aimed therefore at evaluating the temporal and spatial expression of Muc1 at different stages of rat development. In this report, 80 animals were included: 64 rat foetuses at 13, 14, 15, 16, 17, 18, 19 and 20 days of gestation from pregnant females (WKAH/Hok), 8 embryos each stage. Standard immunohistochemistry was performed using anti-MUC1 cytoplasmic tail polyclonal antibody (CT33). The reaction was considered positive when more than 5% of the cells were stained; reaction patterns were: L = linear, membrane, C = cytoplasmic and M = mixed; nuclear staining was also recorded. Intensity was graded as negative (−), low (+), moderate (++) and strong (+++). Muc1 expression was observed with a low intensity on 13th day (13 D) in the stomach, lung and kidney; at 14 d, small intestine and pancreas were also reactive; at 16 D, liver and esophagus and at 18 D, trachea and salivary glands. During the development, intensity increased while the pattern of expression changed: at the first days of gestation, it was predominantly linear and apical while during further development an increase in cytoplasmic expression was observed. Trachea, stomach, kidney and lung epithelia were the more reactive tissues. In specimens belonging to neonates and adults, all tissues analyzed showed similar Muc1 expression. The findings of this study assess that Muc1 is highly expressed in the epithelial rat embryonic development.

MUC1 immunotherapy

The overexpression and aberrant glycosylation of MUC1 is associated with a wide variety of cancers, making it an ideal target for immunotherapeutic strategies. This review highlights the main avenues of research in this field, focusing on adenocarcinomas, from the preclinical to clinical; the problems and possible solutions associated with each approach; and speculates on the direction of MUC1 immunotherapeutic research over the next 5-10 years.