Tretinoin induces bone marrow collagenous fibrosis in acute promyelocytic leukaemia: new adverse, but reversible effect.

In 11/13 acute promyelocytic leukaemia (APL) cases treated with tretinoin (RA) we observed RA-induced inaspirable collagenous fibrosis of the bone marrow. To study the mechanism of RA on collagen production, we cultured a human bone marrow derived stromal cell line and an osteoblastic cell line with RA in vitro. 10(-7) and 10(-6)M of RA stimulated collagen production. Clinical and experimental observation may be important to understand this adverse effect of RA as it is useful in cancer chemoprevention as well as treatment for APL. This adverse effect is spontaneously reversible after stopping RA or following chemotherapy.