Virtually all cancer treatments are designed to kill cancer

Virtually all cancer treatments are designed to kill cancer cells, usually by inducing apoptosis. However, one particular cancer - acute promyelocytic leukemia(APL) - has been successfully treated with all-trans-retinoic acid, which causes the promyelocytes to differentiate into neutrophils. How might a change in the state of differentiation of APL cancer cells help the patient?

Solution

Acute promyelocytic leukemia is a type of a cancer of the white blood cells.
The disease is characterized by a chromosomal translocation involving the retinoic acid receptor alpha (RAR or RARA) gene and is distinguished from other forms of AML by its responsiveness to all-trans retinoic acid (ATRA; also known as tretinoin) therapy.
In 95% of cases of APL, retinoic acid receptor-alpha (RARA) gene on chromosome 17 is involved in a reciprocal translocation with the promyelocytic leukemia gene (PML) on chromosome 15, a translocation denoted as t.
all-trans retinoic acid does not directly kill the malignant cells. ATRA resulted in terminal differentiation of APL cells. If this terminal diffentiation could be controoled then cells might not proliferate.
The development of drugs that selectively act on APL cells may contribute to increasing the therapeutic efficacy of APL treatment as well as elucidating the mechanisms of response to ATRA.
A study done by Makishma et. al. 9-cis retinoic acid alpha-tocopherol ester (9CTT) inhibited the proliferation of APL cells and induced differentiation markers, such as granulocytic maturation. 9CTT, alone or in combination with other retinoids, may be useful for the treatment of APL.