Detection of Circulating Anti-Mucin 1 (MUC1) Antibodies in Breast Tumor Patients by Indirect Enzyme-Linked Immunosorbent Assay Using a Recombinant MUC1 Protein Containing Six Tandem Repeats and Expressed in Escherichia coli

Abstract

Mucin 1 (MUC1), a tumor-associated antigen, is a transmembrane glycoprotein expressed by normal epithelial cells and overexpressed by carcinomas of epithelial origin. Autoantibodies against MUC1 are often found in circulation, either free or bound to immune complexes, which might contribute to limit tumor outgrowth and dissemination by antibody-dependent cell-mediated cytotoxicity, and were found favorably predictive of survival in early breast cancer patients. There is no commercial enzyme-linked immunosorbent assay (ELISA) kit for detecting the anti-MUC1 antibodies in human serum thus far. To detect circulating anti-MUC1 antibodies, we established an indirect ELISA (I-ELISA) using a recombinant MUC1 protein containing six tandem repeat sequences of MUC1 after the antigenicity and specificity of the protein were confirmed. The I-ELISA had a sensitivity of 91.3% and a specificity of 94.1% when a competitive I-ELISA was used as a reference test. The results showed that more patients with benign breast tumors (P ‫؍‬ 0.001) and breast cancer patients before primary treatment (P ‫؍‬ 0.010) were found to have anti-MUC1 IgG than healthy women; anti-MUC1 IgG before primary treatment was found more than after primary treatment (P ‫؍‬ 0.016) in breast cancer patients. Interestingly, the anti-MUC1 IgG serum level was reversely correlated to that of CA15-3 antigen in advanced-stage patients (r ‫؍‬ ؊0.4294, P ‫؍‬ 0.046). Our study has demonstrated the suitability of the established I-ELISA for detecting circulating anti-MUC1 antibodies in human serum. Furthermore, we found that circulating anti-MUC1 antibodies may still bind MUC1 shed into blood in stage IV breast cancer, which can support the use of MUC1-target immune therapy strategies.

Tumour‐Associated Autoantibodies as Diagnostic Biomarkers for Breast Cancer: A Systematic Review and Meta‐Analysis

“…After excluding 579 non‐English articles and 1318 duplicates, 4441 articles not relevant to the topic and 58 meeting the exclusion criteria were excluded. Ultimately, 84 articles were included . A total of 196 specific tumour‐associated autoantibodies (Table S1) were reported, of which 23 specific tumour‐associated autoantibodies (Table ) had been studied more than once.…”

Alpha 2HS-glycoprotein, a tumor-associated antigen (TAA) detected in Mexican patients with early-stage breast cancer

“…However, these have been lacking in clinical usefulness because their sensitivity and specificity entertain values of < 70%, although many autoantigens may be detected by antibody-based methods and are considered candidates for oncogenic proteins [10,11,[20][21][22][23][24][25][26][29][30][31][32][33][34][35][38][39][40]. Validation of the most promising biomarkers proposed for the breast cancer diagnosis and prognosis has required the application of high evaluation standards in prospective cohort studies of women with breast cancer.…”

“…Additionally, triosephosphate, isomerase, and cyclophillin A have been identified as autoantigens in breast tumor tissues [34]. Humoral immune response to MUC-1 in patients with benign and malignant breast tumors has been reported [35]. Recently, antibodies have been reported against A1AT in the serum of patients with breast cancer, and alpha 1 antitrypsin has been reported as a TAA in breast cancer at early stages [36].…”

A Multiparametric Serum Marker Panel as a Complementary Test to Mammography for the Diagnosis of Node-Negative Early-Stage Breast Cancer and DCIS in Young Women

“…They are biochemically well-characterized, and many reagents and techniques are available for their detection, simplifying assay development. Until very recently, several specific autoantibodies have been detected in the sera of patients with advanced-stage breast cancer (14,(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58). However, very few studies have attempted to identify and/or evaluate autoantibodies in node-negative earlystage PBC ( 2 cm) or, more importantly, in preinvasive breast cancer, for which mammography's sensitivity is decreased.…”