A meta-analysis of diagnostic challenges in Ph-like ALL at baseline: early detection strategies for personalized therapeutic interventions.

Ph-like ALL is a high-risk subtype with diverse genomic alterations, including CRLF2 rearrangements, JAK2/EPOR mutations, and ABL-class fusions, which are targetable but underdiagnosed in low and middle-income countries (LMICs). This meta-analysis (78 studies, 15,201 patients, 42 countries) highlights disparities in detection and outcomes between high-income countries (HICs) and LMICs. HICs use comprehensive profiling (RNA-seq: 90-95% sensitivity), while LMICs rely on limited FISH/qPCR, detecting only 30-50% of cases due to cost barriers ($1200 vs. $15-42 for LMIC-adapted assays), infrastructure gaps, and delayed turnaround (4-6 weeks vs. < 7 days). CRLF2 rearrangements are found in 50-60% of cases in HMICs vs. 20-30% in LMICs (p < 0.001), while ABL-class fusions are missed in 75% of LMIC patients. Undiagnosed Ph-like ALL correlates with worse survival (5-year OS: 35-45% in LMICs vs. 60-65% in HICs) due to chemotherapy overuse instead of TKIs (e.g., dasatinib improves EFS by 30%). A tiered diagnostic approach, initial CRLF2 flow cytometry ($15, 80% sensitivity), confirmatory PHi-RACE PCR ($42, 95.2% sensitivity), and selective NGS referral could bridge 85% of the detection gap at 90% cost reduction. Cost-effective tools, subsidized NGS networks, workforce training, and WHO-endorsed guidelines could prevent 40-50% of relapses in LMICs.