Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a subtype of pediatric leukemia with high risk factors and poor outcomes. There are few reports of its prevalence in Latin America. Researchers of a study published in Cancer Reports sought to change this. They conducted a study aimed to evaluate the frequency and clinical and biological characteristics of Ph-like ALL in a pediatric cancer center in Colombia.
Researchers assessed data from 121 patients with the Ph-like genetic profile analyzed by a low-density array (LDA). Samples from Ph-like ALL were analyzed using fluorescent in situ hybridization for cytokine receptor like factor 2 (CRLF2) and ABL proto-oncogene 1, non-receptor tyrosine kinase (ABL1) rearrangements. Copy number variations were assessed using multiplex ligation probe amplification.
According to the results, 12.4% of patients had Ph-like ALL, and these patients had significantly higher leukocyte counts at diagnosis and higher levels of minimal residual disease on days 15 and 33 of induction compared to patients without the Ph-like subtype. There were no significant differences in sex, age, or response to prednisone at day 8 between the two groups, the researchers noted. CRLF2 rearrangements were found in eight patients, and ABL1 rearrangements were identified in two patients. The researchers noted that other genetic alterations alone or in combination were identified in 77% of patients, including deletions in cyclin dependent kinase inhibitor 2 A/B (46.2%), IKAROS family zinc finger 1 (38.3%), and paired box 5 (30.8%).
“Ph-like ALL had a 12.4% prevalence in our cohort of patients with pediatric ALL. The identification of this group of patients has importance for risk stratification and future targeted therapy,” the researchers concluded.