The anti-tumor activity was not due to direct effects on tumor cells as the CT-26 cell line was insensitive to pan-PI3K (GDC-0941), dual β/δ (AZD8186) and α/δ (AZD8835) and isoform selective PI3Kδ inhibitors (CAL-101) with IC50s > 4 μM (Table 2). Here, PIK3CD is linked to neoplasm.