Metastatic human melanoma cells wer

Metastatic human melanoma cells were first shown to exert potent engulfment activity directed against both inert material and apoptotic cells15 (Fig. 1a). The fact that this activity was a property of metastatic cells, while virtually absent in melanoma cells deriving from primary tumours, piqued interest in the field that engulfment activity could be selected during cancer progression. Metastatic melanoma cells were able to engulf and digest even live cells, an activity seemingly unrelated to macrophage behaviour. This observation suggested that these malignant cells might have acquired a broad activity to engulf both live and dead cells, potentially in order to feed, an activity that was called cannibalism. When metastatic melanoma cells were co-cultured with live lymphocytes, they were found to cannibalize them at high rates, which allowed the metastatic cells to survive even under serum-starved conditions, while the ingestion of latex beads had no effect to promote survival, and cancer cells died quickly7. These findings established cell cannibalistic activity, directed towards dead cells, live cells and even cells of a different cell type (T cells), as an important metabolic adaptation of cancers.