In the study reported here, we analyzed the anti-tumor activity of the individual PI3K class I isoform inhibitors, Alpelisib (BYL-719; p110α), TGX-221 (p110β), CZC24832 (p110γ), and Idelalisib (CAL-101; p110δ), on a panel of RMS cell lines (Figure 1). The gene discussed is PIK3CD; the disease is neoplasm.