Abstract 5484: Childhood leukemia and lymphoma: African experience supports a role for environmental factors

Abstract

Abstract Major differences exist in the nature of leukaemia and lymphoma (Le/Ly) in low-income African children (LIAC) compared to those of high-income world (HIW). These include the absence of the peak incidence of acute lymphoblastic leukemia (ALL) in the first quinquennium (FQ) that characterizes the disease in HIW. Conversely, chloroma association with acute myelogenous leukemia (CA-AML) and Burkitt's lymphoma (BL) are rare in HIW. In 1982-1984, using standard international study protocol, we performed immunophenotypic characterisation (IPC) in 86 Le/Ly patients, including 18 < 15 years, 21 ≥15 years ALL patients; 6 AML, 23 chronic lymphocytic leukaemia (CLL) and 18 non-Hodgkin's lymphoma (NHL) patients. Rearrangement (GR) of immunoglobulin and T-cell receptor genes was evaluated in 19/32 samples. IPC/GR confirmed ALL subtypes as “common”: 4 (22.2%), null: 2 (11.1%), T: 7 (38.9%), B: 4 (22.2%), and 1 (5.6%) unclassifiable among ≤ 15 years and 8 (38.1%), 1(4.8%), 11 (52.4%) 1 (4.8%) and 0 (0.0%) ≥.15 years. These and other cases of Le/Ly in Ibadan/Nigeria (population > 2x106) were studied for spatial clustering, while the incidence (x10−5) of childhood ALL (CAL) subtypes was estimated and compared with those of contemporary populations elsewhere. Reduced incidence of CAL in Ibadan was due to depletion of c-ALL and absence of FQ-ALL, and correlated inversely with the incidence of Burkitt's lymphoma (BL) and of chloroma-associated AML (CA-AML). C-ALL predominated in low-density/higher socio-economic (SES), vis-a-vis BL and CA-AML in high-density/lower SES lifestyle areas. The aberrant response model, which has been hypothesized for the high prevalence of c-ALL in HIW may also serve to explain the opposite pathology in LIAC. It is proposed that either an identical or closely related etiological pathway is shared by all three disorders. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5484. doi:1538-7445.AM2012-5484