This paper from 2020 reviews evidence relating to the availability of many bioactive substances such as vitamins, polyphenols, sulfides, glucosinolates and antioxidants that make broccoli consumption important in “green chemoprevention”.
Nandini DB, Rao RS, Deepak BS, Reddy PB. Sulforaphane in broccoli: The green chemoprevention!! Role in cancer prevention and therapy. J Oral Maxillofac Pathol. 2020 May-Aug;24(2):405. doi: 10.4103/jomfp.JOMFP_126_19. Epub 2020 Sep 9. PMID: 33456268; PMCID: PMC7802872. https://pubmed.ncbi.nlm.nih.gov/33456268/