The PI3K Type IA catalytic subunit p110δ was detected in 100% of stage 1–2 (7/7), 86% of stage 3 (6/7) and 67% of stage 4 (6/9) (Figure 1A) with overall protein levels of p110δ significantly lower in stage 4 as compared with stage 1–2 neuroblastoma (p = 0.04) (Figure 1B). Here, PIK3CD is linked to neuroblastoma.