To explore whether RPG haploinsufficiency leads to rRNA maturation defects also in cancer cells, we decided to analyze rRNA maturation across pediatric acute lymphoblastic leukemia (ALL) samples harboring CDKN2A (9p) deletions with and without concurrent deletion of RPS6. Deletions targeting CDKN2A are present in 20–30% of B‐cell ALL and 95% of T‐cell ALL. Here, CDKN2A is linked to acute lymphoblastic leukemia.