The present disclosure relates to a method of inhibiting tumor growth. More specifically, the present disclosure relates to the use of monoclonal antibodies for targeting truncated O-glycans on glycoproteins to inhibit activation of pro-survival ceil signaling pathways, to inhibit tumor growth. For example, monoclonal antibody AR9.6 may be used to target truncated O-glycans on the MUC16 glycoprotein, thereby inhibiting the phosphatidyiinositol 3-kinase/Akt (Pi3K/Akt) signaling pathway.