Further exploration of this rare variant SNP, CYP2B6 rs3211371, through a rapid growth sequencing technology and a high-density SNP genotyping array [30, 31] will enable us to have increasing opportunities to swiftly detect rare genetic alleles, and to further investigate whether these rare variants could determine the responses to treatments and the subsequent prognoses of breast cancers. This evidence concerns the gene CYP2B6 and breast cancer.