CD4 and neoplasm: Specifically, pGSN has been implicated in the following processes: (1) exosomal secretion and conferring of chemoresistance in otherwise chemosensitive OVCA cells; (2) autocrine and paracrine feedback mechanism of pGSN expression; and (3) exosomal-mediated downregulation of tumor-killing immune cells such as CD8+ T cells, CD4- T cells, M1 macrophages and natural killer cells.