Although research on circulating RNAs in CRC remains nascent, circRNAs have shown unique therapeutic value: 1) acting as competitive inhibitors of microRNAs to modulate immune responses (77); 2) serving as stable vaccine vectors encoding tumor antigens to enhance anti-tumor immunity via activation of CD8+/CD4+ T cells and dendritic cells (116–118); and 3) synergizing with combination therapies such as CAR-T (chimeric antigen receptor T-cell) (119, 120). The gene discussed is CD4; the disease is neoplasm.