Abstract 4198: Epidemiological and molecular analysis of acute lymphoblastic leukemia in the pediatric population of Puerto Rico
Authors: Montes-Rodriguez Ingrid M. , Torres-Cintron Carlos R. , Soto-Salgado Marievelisse , Suarez Erick , Rivera-Concepcion Joel , Cadilla Carmen L. , Clavell Luis A. 
Published: August 2019

Background: Acute lymphoblastic leukemia (ALL) accounts for 80% of leukemias diagnosed in children. In United States (US), ALL accounts for 27% of cancers diagnosed in children 0 to 19 years old, disproportionally affecting children between 2 and 5 years. Even though ALL age patterns are consistent across racial/ethnic groups, the incidence and mortality of this malignancy is highly variable. For example, Hispanics have a higher incidence of ALL and lower survival rates when compared to non-Hispanic patients, with higher likelihood of recurrence. However, Hispanic is a broad category used to refer to subpopulations of Mexican, Cuban, Puerto Rican, South or Central American, Dominican, or individuals with other Spanish descent. Hence, the cancer data that is reported for Hispanics is aggregated, masking important differences between these subpopulations that, due to genetic admixture over 500 years, have unique biologic and non-biologic factors associated with disease outcome.

Objective: The objective of this study was to assess the racial/ethnic group differences in children diagnosed with ALL in Puerto Rico (PR) and to compare incidence and mortality risk with US Hispanics (USH), non-Hispanic-white (NHW) and non-Hispanic-black (NHB). To access these differences, we estimated the Standardized Rate Ratio (SRR) for 2010-2014. Furthermore, we aimed to characterize the ALL genetic subtypes in the PR population.

Methods: Secondary data-analysis of the Puerto Rico Central Cancer Registry (PRCCR) and the National Cancer Institute’s Surveillance, Epidemiology, and End Results program (SEER) databases was performed for the 2010-2014 period. We also described the childhood ALL sub-types more prevalent in PR for the years 2014-2015 using the pathology reports at the PRCCR.

Results: Our data shows that PR children have lower ALL incidence and mortality risk than USH, lower incidence but higher mortality risk than NHW, and higher incidence and mortality risk than NHB. The most prevalent ALL subtypes in Puerto Rico (n=50 for the years 2014-2015) were B-ALL (n=42) and T-ALL (n=8). The most common chromosomal aberration was the ETV6-RUNX1 translocation, found in 8 of 50 (16%) of the cases, followed by Hyperdiploidy and IGH-gene rearrangements, each found in 4 of 50 of the cases (8%).

Conclusion: The observed differences in ALL incidence and mortality among PR and USH children may be related to their genomic background, environmental exposures, and/or gene environment interactions. Future research is warranted to elucidate the factors contributing to this racial/ethnic disparity.

Citation Format: Ingrid M. Montes-Rodriguez, Carlos R. Torres-Cintron, Marievelisse Soto-Salgado, Erick Suarez, Joel Rivera-Concepcion, Carmen L. Cadilla, Luis A. Clavell. Epidemiological and molecular analysis of acute lymphoblastic leukemia in the pediatric population of Puerto Rico [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4198.