Actions of free ISG15 in some cancer types
| Cancer type | Actions | Reference |
|---|---|---|
| PDA | TAMS from patients with PDA exhibits a high ISG15 expression. TAM secretes ISG15, increasing the phenotype of CSCs. Moreover, IFN-β promotes that CSCs also secrete ISG15 | [62] |
| Melanoma | Soluble ISG15 is secreted to medium from melanoma cells, promoting E–cadherin expression on human dendritic cells | [63] |
| ESCC | Patients with ESCC have increased ISG15 expression High levels of free ISG15 are found in the plasma of patients with ESCC compared with healthy patients | [64] |
| Breast cancer | Exogenous-free ISG15 reduces tumor growth in athymic mice by promoting NK cell infiltration Intracellular-free ISG15 promotes the expression of MHCI | [65] |
| OSCC | Free ISG15 interacts with Rac1-GDP, promoting cell migration in an ISGylation-independent manner. This event has been related to lymphatic metastasis of OSCC | [66] |
PDA: pancreatic ductal adenocarcinoma; TAMs: tumor-associated macrophages; ESCC: esophageal squamous cell carcinoma; MHCI: major histocompatibility complex I; OSCC: oral squamous cell carcinoma; CSCs: cancer stem cells