Patients suffering from acute promyelocytic leukemia (APL) are now routinely given all-trans-retinoic acid (ATRA). This causes the cancer cells to return to their normal function – a therapy known as differentiation and helps cure 70% of all APL sufferers. Differentiation was discovered by Professor Leo Sachs of Israel’s Weizmann Institute.
http://wis-wander.weizmann.ac.il/reversing-malignancy
http://www.medterms.com/script/main/art.asp?articlekey=19760