It may be that these types of cancer are less sensitive to IGF-1, or that other risk factors such as smoking are dominant, Dr Knppel comments
[DOI] [PMC free article] [PubMed] [Google Scholar] Seibold A, Williams B, Huang ZF, Friedman J, Moore RH, Knoll BJ, et al
Ferric iron (Fe 3+ ) is stored within ferritin in the cytoplasm, whereas Fe 2+ for ferroptosis induction is either imported via CD44 from the extracellular compartment [22] or provided via lysosomal ferritin degradation and subsequent reduction [23]
Again, though, these actions are largely characterized in cell and animal systems, and their relevance to visible human skin change depends entirely on whether an effective concentration reaches the dermis by the route in question