A new study provides a biological rationale for the worse prognoses seen in Hispanic/Latino children diagnosed with B-cell acute lymphoblastic leukemia (B-ALL). In a Letter to the Editor published in Leukemia, researchers discussed data demonstrating that IGH-CRLF2 translocation and IKZF1 deletion provide the basis for this health disparity.
In their study, Raca et al examined clinical and molecular data from 239 pediatric patients with B-ALL treated at Children’s Hospital Los Angeles, of the University of Southern California Keck School of Medicine. Of them, 164 self-reported as Hispanic/Latino.
There was a significantly increased incidence of IGH-CRLF2 translocation in Hispanic/Latino patients compared with non-Hispanic/Latino patients (12.0% vs 2.7%; P =.026). However, there was no significant difference in the incidence of P2RY8-CRLF2 fusion in Hispanic/Latino and non-Hispanic/Latino patients.
Hispanic/Latino patients had a higher incidence of IKZF1 deletion compared with non-Hispanic/Latino patients (29% vs 15%; P =.016). According to the researchers, “these results suggest that IKZF1 deletion is a novel biological determinant of the health disparity in pediatric B-ALL for Hispanic/Latino children.”
Previous research in high-risk pediatric B-ALL showed that CRLF2 gene rearrangement is associated with deletion of the IKZF1 tumor suppressor. Therefore, the researchers analyzed the incidence of patients with concomitant IKZF1 deletion and CRLF2 translocations.
Concomitant IKZF1 deletion with CRLF2 translocation was increased in Hispanic/Latino patients compared with non-Hispanic Latino patients (12.0% vs. 0%; P <.001). Particularly, the IgH-CRLF2 translocation was increased 9-fold in this population compared with the P2RY8-CRLF2 fusion in patients with IKZF1 deletion.
“These data demonstrate that the IGH-CRLF2 translocation, the IKZF1 deletion, and the concomitant IKZF1 deletion with IGH-CRLF2 translocation are highly increased in B-ALL of children in the Hispanic/Latino population,” the researchers concluded.
Raca G, Abdel-Azim H ,Yue F, et al. Increased incidence of IKZF1 deletions and IGH-CRLF2 translocations in B-ALL of Hispanic/Latino children—novel health disparity. Leukemia. Published online February 2, 2021. doi:10.1038/s41375-021-01133-4