Page 16 - Read Online

Page 12 of 16 Nagayama. J Cancer Metastasis Treat 2021;7:6 I http://dx.doi.org/10.20517/2394-4722.2020.114

Figure 3. The consequences of autophagy activation in cancer cell phenotype/fate. Autophagy contributes cancer cell survival by
providing nutrients, but conversely can induce apoptotic or autophagic cell death. Autophagy also re-differentiates cancer cell

CONCLUSION
The physiological role for autophagy in the thyroid is relatively clear that studies with genetically
engineered mice show that basal level of autophagy is required for maintenance of cell homeostasis and
survival, and elevated autophagy, in TSH-stimulated condition, is needed for providing building blocks for
sufficient synthesis of proteins including TG. Regarding its pathological role in thyroid cancer initiation,
there is some evidence indicating anti-tumorigenic effect of autophagy on cancer initiation in general, but
so far nothing in thyroid cancer. Regarding thyroid cancer progression and autophagy-targeted treatment,
the data are controversial, some reporting pro-survival/proliferative, but others showing anti-survival/
proliferative and context-dependent effects of autophagy on thyroid cancer. Further studies are needed
to elucidate the molecular mechanisms for the complex relationship between autophagy and its effect on
thyroid cancer behaviors. Finally, precise monitoring of autophagic flux is highly critical for these studies.

DECLARATIONS
Authors’ contributions
The author contributed solely to the article.

Availability of data and materials
Not applicable.

Financial support and sponsorship
This work was in part supported by the Japan Society for the Promotion of Science (KAKENHI Grant No.
19K09028).

Conflicts of interest
The author declared that there are no conflicts of interest.

Ethical approval and consent to participate
Not applicable.

Consent for publication
Not applicable.

Copyright
© The Author(s) 2021.