A trend towards a reduction in T cell abundance, with a lower percentage of CD4+ T cells after injection of tumor cell–derived extracellular vesicles (67 % vs. 44.5 % after injection of serum extracellular vesicles, p < 0.05) and a higher percentage of CD8+ T cells (35 % vs. 26 %, tumor cell–derived vs. serum-derived, p < 0.05) was observed. The gene discussed is CD4; the disease is neoplasm.