American researchers have preliminarily confirmed that broccoli and other cruciferous vegetables are rich in compounds called cyanogen isosulfate(ITC), which can preferentially kill the mutant P53 gene and leave the P53 gene. The protein composed of P53 genes can help prevent the growth of cancer cells, but once the P53 gene is mutated, there will not be protection. And the mutated P53 gene is related to almost half of human cancers.
The reason why broccoli can prevent cancer is because it contains substances that can eliminate the mutant P53 gene and retain the normal P53 gene.