CYP24A1 and breast cancer: However, because this amplification is complex, with multiple subregions and many genes co‐amplified with CYP24A1, it is difficult to determine the extent to which increased CYP24A1 expression contributes to disease progression.(53, 70) Although cellular studies have demonstrated oncogenic properties of CYP24A1 in vitro,(53) expression of CYP24A1 protein in human breast cancers is not consistently elevated.