Poorly differentiated tumors are negative for PCDH17. In addition, in non-neoplastic esophageal epithelia, PCDH17 was expressed in the spinous cell layers, implying that this fact may be dependent on the status of cell differentiation and that the silenced expression acts on the de-differentiation of esophageal neoplasms (Haruki et al., 2010). The gene discussed is PCDH17; the disease is neoplasm of esophagus.