Table 1.
Comparison Between MUC1 and MUC4 Attributes
| MUC1 | MUC4 | |
|---|---|---|
| Transmembrane mucin | Yes | Yes |
| Number of VNTR | 20–125 | 146–396 |
| VNTR motif | GSTAPPAHGVTSAPDTRPAP | TSSASTGHATPLPVTD |
| Oncogenic subunit | Yes | Yes |
| MAbs against α subunit | Multiple | None |
| MAbs against β subunit | 2 | Few, but most lack specificity |
| IHC with MAbs against α subunit | +++++ | − |
| IHC with MAbs against β subunit | + | +++ |
| Expression pattern on normal epithelial cells | Apical | Apical |
| Expression pattern on malignant cells | Apical, entire membrane, cytoplasmic | Apical, entire membrane, cytoplasmic |
| Shedding | Yes | Yes |
| Signal-transducing β subunit | Yes | Yes |
| Length of β subunit extracellular domain | 58 aa | 725 aa |
| Length of cytoplasmic domain | 72 aa | 22 aa |
| β Subunit-like splice variants Y and Z | Yes | Yes |
VNTR, variable numbers of tandem repeat; MAbs, monoclonal antibodies; IHC, immunohistochemistry; aa, amino acid.