Checkpoint Inhibitor-induced Liver Injury

Inclusion Criteria: Both patient groups and control group: • Able to give written informed consent OR Potential participants who have developed encephalopathy related to ChILI as a response to checkpoint inhibitor therapy, who lack the capacity to give written informed consent and have a consultee (personal or nominated) - for ChILI patient group only ChILI group: Patients who developed checkpoint inhibitor-induced liver injury and meet the following criteria: 1. Meets one of the following analytical thresholds at enrolment (visit 1) * Alanine transaminase (ALT) exceeding 5 times the upper limit of normal (ULN) OR * ALT exceeding 3 times ULN plus bilirubin exceeding 2 times ULN OR * Alkaline phosphatase (ALP) exceeding 2 times ULN with accompanying elevations of gamma-glutamyl transferase in the absence of known bone metastases driving the rise in ALP level 2. Absence of other known causes of liver injury after detailed investigations Patients who developed ChILI but did not meet the above criteria at enrolment or who were found to have a different cause for their liver injury after further investigations will be excluded from the analysis Control group: Consecutive patients with cancer who have a clinical indication to start checkpoint inhibitors. A small proportion of patients will develop ChILI following their checkpoint inhibitor treatment and will be classified as cases. Exclusion Criteria: * Patients who are treated with cytotoxic chemotherapy concurrently with checkpoint inhibitors. * On the judgment of chief investigator that the person has certain alternative explanations to the acute event (rather than ChILI).