title: Bcl-2 protein and apoptosis in pediatric acute lymphoblastic leukemia.
abstract: Many chemotherapeutic agents are thought to exert their genotoxic effects through induction of programmed cell death (PCD) (apoptosis) in tumor cells. The bcl-2 is an anti-apoptotic oncoprotein and can confer a survival advantage to tumor cells by preventing apoptosis. Overexpression of bcl-2 may therefore be implicated in resistance to chemotherapy. We studied the significance of bcl-2 expression and the PCD index in pediatric acute lymphoblastic leukemia. Evaluation of bcl-2 by immunocytochemistry and PCD by an enzymatic end labelling technique using biotin-dUTP was carried out in a total of 55 cases and 40 controls. Bcl-2 was found to be expressed in 47% (26/55) of the acute lymphoblastic leukemia cases. The positive cells varied from 0-49% among individual samples. Pre-treatment (spontaneous) apoptosis was observed in 62% (34/55) cases. The mean pre-treatment PCD index was 8.27 1.3%, while the median PCD index was 5. The PCD value for the leukemic samples analyzed were then classified as either high apoptosis values ( 5) and low apoptosis values (<5). PCD index was high in 53% (29/55) and low in 47% (26/55). However, 23% (13/55) of cases did not show presence of either apoptosis or bcl-2. There was no association between clinical and laboratory parameters with the apoptotic index or bcl-2 protein expression. However, evaluation of apoptotic index and bcl-2 expression on day 7 of induction chemotherapy showed a borderline correlation between these markers and initial WBC count, presence of mediastinal mass and hepatosplenomegaly. Follow-up of these patients is being done to look for any association between treatment response and apoptosis.
authors.affiliation: Division of Laboratory Medicine, Regional Cancer Centre, Thiruvananthapuram, India.
authors.forename: G
authors.initials: G
authors.lastname: Srinivas
authors.forename: P
authors.initials: P
authors.lastname: Kusumakumary
authors.forename: M K
authors.initials: MK
authors.lastname: Nair
authors.forename: K R
authors.initials: KR
authors.lastname: Panicker
authors.forename: M R
authors.initials: MR
authors.lastname: Pillai
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017209:Apoptosis; D001853:Bone Marrow / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D002467:Cell Nucleus / Q000737:chemistry; D002648:Child; D003593:Cytoplasm / Q000737:chemistry; D006801:Humans; D018655:Lymphocyte Count / Q000187:drug effects; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D019253:Proto-Oncogene Proteins c-bcl-2