In the esophageal cancer lesions, PIK3R1 was expressed in 65.5% (19/29) cases (+: 18; ++: 1; +++: 0), PTEN was expressed in 48.3% (15/31) cases (+: 14; ++: 1; +++: 0), and RASSF1 was expressed in 56.7% (17/30) cases (+: 14; ++: 3; +++: 0). The gene discussed is PIK3R1; the disease is esophageal cancer.