Topical sirolimus is increasingly being used in the treatment of several skin disorders. We previously demonstrated in a double-blind study that applying topical sirolimus for 12 weeks was effective in reducing the risk of keratinocyte cancer among solid organ transplant recipients. Additionally, we found a reduction in actinic keratoses at 12 weeks and the occurrence of intraepidermal carcinomas 24 months after treatment (1). We decided to apply Visium Spatial Transcriptomics to gain deeper insights into patients’ skin samples at 12 weeks of treatment (n=10 treated vs. n=10 placebo). We identified for the first time the effect of sirolimus on keratinocytes: downregulation on cell proliferation and mitosis, impairment on the differentiation process through increase in keratin 14 and integrin expression, as well as downregulation of NOTCH signaling. Moreover, under mTor inhibition, some of the mitochondrial complexes involved in the electron transport chain were significantly downregulated, highlighting a potential pivotal role of mitochondria in carcinogenesis. Our study revealed a rewiring of metabolism not only in keratinocytes at a late stage of differentiation but also at early stages and in the basal layer. This indicates that the effect begins earlier in the process. In conclusion, our findings highlight that the chemopreventive effect of mTor inhibition is primarily mediated through an imbalance of differentiation and proliferation, which can be triggered by the metabolic rewiring.