Background: Imatinib mesylate, a tyrosine kinase inhibitor specifically targeting the BCR/ABL fusion protein, induces hematological remission in patients with chronic myeloid leukemia (CML). However, the majority of CML patients treated with imatinib develop resistance with prolonged therapy. Dendrophthoe pentandra (L.) Miq. is a Malaysian mistletoe species that has been used as a traditional treatment for several ailments such as smallpox, ulcers, and cancers. Methods: We developed a resistant cell line (designated as K562R) by long-term co-culture of a BCR/ ABL positive CML cell line, K562, with imatinib mesylate. We then investigated the anti-proliferative effects of D. pentandra methanol extract on parental K562 and resistant K562R cells. Trypan blue exclusion assays were performed to determine the IC50 concentration; apoptosis and cell cycle analysis were conducted by flow cytometry. Results: D. pentandra extract had greater anti-proliferative effects towards K562R (IC50= 192 μg/mL) compared to K562 (500 μg/ mL) cells. Upon treatment with D. pentandra extract at the IC50. concentration: K562 but not K562R demonstrated increase in apoptosis and cell cycle arrest in the G2/M phase. Conclusion: D. pentandra methanol extract exerts potent anti-proliferative effect on BCR/ABL positive K562 cells.
We report two cases of biphenotypic acute leukaemia diagnosed in Hospital Universiti Kebangsaan Malaysia (HUKM), their clinical, haematological characteristics and response to chemotherapy. Both patients are middle-aged ladies who presented with hepatosplenomegaly and high white cell count, mainly composed of blast cells. Their bone marrow aspirations were hypercellular comprising of more than 90% heterogenous blast cells. Cytochemical analyses show more than 3% positivity towards peroxidase, with smaller blasts showing block positivity towards PAS. Immunophenotypically, the blasts showed dual expression of CD 33 and CD 19, CD 19 and CD34, intra CD22, intra TdT and intraMPO. One of the patients showed presence of the Philadelphia chromosome on cytogenetic analysis which was confirmed by Fluorecsence In Situ Hybridisation (FISH). Molecular analysis also showed presence of the BCR-ABL fusion protein. Both patients were given combination chemotherapy consisting of daunorubicin and cytosine arabinoside.However, the patient with positive Philadelphia chromosome BCR-ABL did not achieve morphological remission after induction chemotherapy. In view of the poor prognosis of this disease, both the patients were planned for upfront peripheral blood stem cell transplantation.
Childhood acute lymphoblastic leukaemia (ALL) is a heterogenous disease in which oncogene fusion transcripts are known to influence the biological behaviour of the different ALL subtypes. Screening for prognostically important transcripts is an important diagnostic step in treatment stratification and prognostication of affected patients. We describe a SYBR-Green real-time multiplex PCR assay to screen for transcripts TEL-AML1, E2A-PBX1, MLL-AF4, and the two breakpoints of BCR-ABL (p190 and p210). Validation of the assay was based on conventional karyotyping results. This new assay provides a rapid, sensitive, and accurate detection method for prognostically important transcripts in childhood ALL.