To assess the functionality of OGT in mediating sensitivity to inhibition of PI3K by GDC-0941, we used siRNA pools targeting OGT to knockdown the expression of OGT in the GDC-0941-resistant MDA-MB-231 and OVCAR-4 tumor cell lines, and then assayed for cell proliferation and phosphorylation status of multiple signaling pathways, including downstream effectors of PI3K (Fig. 4). This evidence concerns the gene OGT and neoplasm.