RAB11B and esophageal cancer: However, according to the recommendation of the Worldwide Esophageal Cancer Collaboration (WECC) (4), the yp stage groups comprised the ypT stage groups (ypT0-2, ypT3, ypT4a, and ypT4b) different from the seventh and eighth AJCC pathologic T stage groups and ypN stage groups (ypN0, ypN1, ypN2, and ypN3) consistent with the seventh and eighth AJCC pathologic N stage groups.