CD99 and neoplasm: Figure 6 summarizes the effects of CD99 triggering by antibodies. Most likely, tumor cells that are forced to grow by oncogenic stimuli cannot recover stressful signals such as those induced by CD99 triggering and thereby become more vulnerable than normal cells. Antibodies directed toward CD99 can also be used to develop radio–immuno compounds [99] that may detect CD99-positive tumors and metastatic sites with high sensitivity, outperforming FDG-PET in preclinical studies.