Figure 4.

Autophagy in malignant transformation and tumor progression

(A) Healthy cells appear to be protected from malignant transformation by proficient autophagic responses. Conversely, autophagy promotes tumor progression and therapy resistance in a variety of models. Thus, the transition of a healthy cell toward a metastatic and therapy-insensitive neoplasm may involve a temporary (but not a stable) loss in autophagy competence. The mechanisms underlying the restoration of proficient autophagic responses after malignant transformation remain to be elucidated. (B, C) In specific settings, oncogenesis and tumor progression may rely on a permanent loss (B) or gain (C) of autophagic proficiency.