STAT3 and neoplasm: In contrast, copper chelators such as Dextran-catechin or ﻿Tetraethylenepentamine (TEPA) inhibit phosphorylation of Signal transducer and activator of transcription 3 (STAT3) and EGFR, leading to PD-L1 degradation through ubiquitination and bolstering CD8 + T cell and natural killer cell infiltration to curb tumor growth.