Mucin antigens (MUC) (MUC)

Mucin antigens, including MUC1, MUC4, MUC5AC, and MUC16, are high-molecular-weight glycoproteins that are aberrantly overexpressed and glycosylated in exocrine pancreatic cancer cells [1, 2, 13]. In healthy tissues, these proteins provide lubrication and protection to epithelial surfaces, but in pancreatic ductal adenocarcinoma (PDAC), they function as oncoproteins that drive tumor progression, metastasis, and resistance to therapy [3, 5, 8]. These proteins facilitate oncogenic signaling through interactions with pathways such as EGFR, Wnt/beta-catenin, and HIF-1alpha, leading to metabolic reprogramming and epithelial-mesenchymal transition (EMT) [7, 12, 35]. Furthermore, the dense 'mucin shield' contributes to the characteristic desmoplastic stroma of pancreatic tumors, which physically hinders the penetration of chemotherapeutic agents like gemcitabine [2, 4, 36]. Therapeutic strategies targeting these mucins include monoclonal antibodies, antibody-drug conjugates (ADCs), radioimmunotherapy, cancer vaccines, and CAR-T cell therapies, many of which aim to exploit the unique glycoforms present only on malignant cells [14, 19, 33]. Additionally, mucins serve as critical biomarkers for diagnosis and prognosis, with serum levels of MUC5AC and MUC16 (CA125) often correlating with disease stage and treatment response [10, 17, 33].

Other names

Mucin-associated antigensTumor-associated mucinsMucin 1 (MUC1)Mucin 4 (MUC4)Mucin 5AC (MUC5AC)Mucin 16 (MUC16)Cancer antigen 125 (CA125)Epithelial membrane antigen (EMA)CA 15-3CA 27.29hPAM4 antigen

Drugs targeting mucin antigens work through several mechanisms: monoclonal antibodies (e.g., NPC-1C, TAB004) and radioimmunoconjugates (e.g., Clivatuzumab tetraxetan) bind to specific glycoforms to induce antibody-dependent cellular cytotoxicity (ADCC) or deliver localized radiation [14, 15, 28]; peptide inhibitors (e.g., GO-203) block the oncogenic signaling of the cytoplasmic tail [16]; cancer vaccines (e.g., TG4010, GVAX) stimulate T-cell mediated immune responses against tumor-specific mucin epitopes [14, 19]; and small molecules (e.g., Bosutinib) can downregulate mucin expression at the transcriptional level [6, 11].