PF4691502 is a potent inhibitor of the PI3K/mTOR signaling pathway, which plays a critical role in cell growth, proliferation, and survival. It is primarily used in research settings to study oncogenic signaling pathways in cancer cells. Due to its ability to simultaneously target PI3K and mTOR, it is employed in preclinical studies to evaluate the efficacy of dual inhibition in tumor suppression. It has shown activity in models of solid tumors, particularly those with dysregulated PI3K pathway activity, such as breast, lung, and prostate cancers. Its application extends to combination therapy studies, where it is tested alongside chemotherapeutic agents or other targeted therapies to assess synergistic effects. Because of its research utility, it aids in understanding resistance mechanisms and pharmacodynamic responses in cancer cell lines and xenograft models.