Its linear mRNA product and the CYP24A1 protein have been reported to be expressed at elevated levels in many primary lung and other cancers, and in many lung cancer cell lines, including A549; no amplification of the CYP24A1 gene has been reported in A549 [14]–[19], although CYP24A1 is frequently amplified and mutated in primary human cancers [20]. Here, CYP24A1 is linked to lung cancer.