Abstract 5028: Epidemiology of childhood leukemia/lymphoma in resource-poor countries: Nature's manifestation of Ludwik Gross's experiments on environmental influence on animal leukemogenesis.

Abstract

Abstract Epidemiological features of childhood hematological neoplastic diseases (CHND) in resource-poor countries (RPC) that differentiate them from those of affluent countries (AC) include ∼10-fold decreased (DCR) incidence (INC) (x10−5) of common acute lymphoblastic leukemia (c-ALL) subtype, >5-fold increased (ICR) INC of B-ALL subtype/Burkitt's lymphoma (BL), and 20-60-fold ICR INC of chloroleukemia, as well as absence of peak ALL INC among under-5 year olds in RPC (Nigerian data) as compared to AC. To assess lifestyle influences on CHND in an African city, patients (pts) receiving care for CHND at the University College Hospital, Ibadan, Nigeria (IBN) between 9/1982 and 12/1984 underwent routine laboratory assessment and immunophenotypic cell studies, using standard international reagents and indirect fluorescent microscopy. Spatial distribution of cases and disease INC in locales of the city (LC), one of Africa's largest indigenous cities (population 1-2 million), was determined and correlated with lifestyle indices of inhabitants. LC were: central area (75%) lacking in sanitary infrastructure and inhabited by poor illiterate peasant farmers and petty traders (annual income [AI] <$1,000) (zone 1), surrounded by semi-developed area (zone 2) (12.5%), of semi-skilled/literate workers and traders (AI: $1500-$9000) and modern suburbs (zone 3) (12.5%) of educated professionals (AI: >$10,000). In zone 1, BL INC: 1.81-3.62 or >9-fold, AML/AMML± chloroma (CA), INC: 0.41-0.82 or >2-fold, and ALL INC: 0.25-0.50 or 0.3 compared to zone 2+3. BL INC: 0 in zone 3. In zone 1, time-space clustering (TSC) occurred13 times in 35 BL pts, 4 times in 9 AML/AMML±CA pts, but none in ALL. No TSC of BL or AML/AMML±CA, but 3 of ALL in 9 pts occurred in zones 2+3. Conclusion: CHND in IBN is reminiscent of the experiments of Ludwik Gross: following underfeeding of AK mice, a delay in the onset and a reduction in the rate of virus-induced leukemia occurred. Thymectomy inhibited or considerably delayed the development of lymphatic leukemia, and frequently caused the myelogenous forms to appear later in life, often in the form of chloroleukemia. At least, two other hypothetical models have been proposed to explain the pathogenesis of childhood leukemias, including “abnormal immune response to common infection(s)” (Greaves), and “population mixing” (Kinle). There are probably many causes of CHND. Given the high-risk of calorie-malnutrition in zone 1, and the associated risk of maternal and fetal malnutrition causing thymo-lymphatic deficiency, CHND pattern in zone 1 may be Nature's manifestation of the outcome of Gross's experiments, while other models may be relevant for the observation in zones 2+3 of IBN and other RPC. CHND studies in RPC with appropriate technology and reagents could unveil potentials for universal control and prevention of CHND. Citation Format: Christopher K.O. Williams. Epidemiology of childhood leukemia/lymphoma in resource-poor countries: Nature's manifestation of Ludwik Gross's experiments on environmental influence on animal leukemogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5028. doi:10.1158/1538-7445.AM2013-5028