As researchers have found, cancer does not deprive victims of their immune defenses completely, but rather renders the immune system ineffective by means of immunity-suppressing molecules produced by the cancer cells.
此外，近年研究發現，癌症病人並非完全喪失免疫反應，只是癌細胞產生的抑制分子，讓免疫系統變成體液型的無效反應。