This 2020 Rutgers rodent study explored topical application of sulforaphane to prevent UVB-induced skin carcinogenesis:
“We investigated the transcriptomic and DNA methylomic changes during tumor initiation, promotion, and progression and its impact and reversal by sulforaphane (SFN). The production of ROS and inflammation are closely linked to UVB-induced carcinogenesis. SFN protects skin cells from UVB-induced damage mainly through promoting anti-inflammatory, antioxidative and anticancer pathways.
We observed the changes after 2, 15 and 25 weeks of UVB exposure, which would represent the three different stages of skin cancer development. After 2 weeks of UVB exposure, we did not observe any obvious tumors in the UVB group. But after 15 weeks of UVB exposure, some obvious tumors were observed in the skin.
After 15 weeks of UVB treatment in epidermal tissue, the difference between the UVB group and the control group was significantly more than that between the SFN group versus the UVB group. SFN appears to have better cancer-protective effects in earlier time points (weeks 14 and 20) than later time point (week 24). At weeks 20, SFN had significantly fewer tumors with decreased total tumor volume and tumor number.
SFN plays a highly regulatory role in various signaling pathways during UVB irradiation. SFN impacts UVB-induced alterations of DNA methylation profiles, and importantly, SFN treatment attenuates some of these DNA methylation changes. We found a subset of genes associated with SFN treatment, and the relevant changes in gene expression may be driven by promoter CpG methylation status.”
https://cancerpreventionresearch.aacrjournals.org/content/13/6/551 “Epigenome, Transcriptome, and Protection by Sulforaphane at Different Stages of UVB-Induced Skin Carcinogenesis” (not freely available)
We’re getting closer to using epigenetic clocks in sulforaphane studies. This study ignored the 2018 A multi-tissue full lifespan epigenetic clock for mice in favor of their homegrown DNA methylation measurements.
A search of ClinicalTrials.gov didn’t turn up directly relevant human studies.