For instance, both cell lines harbor two common alterations to the PI3K pathway, sharing altered PTEN but differ in having either mutant PIK3CA or PIK3R1. Used together, the similar but distinct genetic backgrounds between the two lines are more reflective of the mutational heterogeneity of patient tumors when studying the hormonal aspects of endometrial cancer than either line alone. Here, PIK3R1 is linked to endometrial cancer.