Inclusion criteria: We included articles that met all of the following conditions: full-text human case reports or case series that provided patient-level data, diagnosis of a malignant neoplasm, regardless of tumor origin or histological subtype, assessment of TA-MUC1 expression by IHC, with preference for those specifying the antibody used and staining/scoring method, TA-MUC1 expression must have been reported in either primary tumors or metastatic lesions, or both, and detailed clinical information, including treatment course, follow-up, or therapeutic outcomes, had to be available. This evidence concerns the gene MUC1 and cancer.