A unique case of acute promyelocytic leukemia showing monocytic differentiation after ATRA (all-trans retinoic acid) therapy.

Acute promyelocytic leukemia (PML) is characterized by a reciprocal translocation between chromosomes 15 and 17 resulting in a chimeric PML and retinoic acid receptor alpha (RARA) oncogene. The resultant fusion protein (PML/RARA) is thought to block differentiation of bone marrow cells arrested at the promyelocytic stage. In vitro and in vivo studies have shown that the large majority of APL cells undergo granulocytic maturation after ATRA therapy.

Analysis of c-kit protein expression in small-cell lung carcinoma and its implication for prognosis.

Recently, therapies targeting signaling pathways involved in the pathogenesis of different tumors have been developed. Studies have shown that the tyrosine kinase inhibitor STI-571 (Gleevec) is used successfully against tumors expressing the c-kit oncogene, such as gastrointestinal stromal tumors (GISTs). A recent in vitro study also demonstrated an antiproliferative effect of STI-571 on small-cell lung cancer (SCLC) cell lines.