Read More on Health"The researchers found that sildenafil-mediated changes in cholesterol metabolism could sensitize cancer cells to cholesterol altering drugs like statins, and actually slow cancer cell proliferation and tumor growth," Lattanzi said. They are intriguing and thought-provoking, but they would need to be validated in human studies in order to inform the management of cancer patients," he said. How The Drug Disrupts Cancer's Fuel SupplyThe study, published in Cancer Research, found that sildenafil blocks an enzyme called phosphodiesterase type 5, or PDE5. That interference leaves cancer cells with less cholesterol to draw on, and the study found that cancer cells are especially vulnerable to that shortage, limiting their ability to spread. Cancer Research.