Kehlen et al. reported that undifferentiated anaplastic thyroid carcinomas expressed larger amounts of APN/CD13 than differentiated thyroid carcinomas, whereas in contrast, higher levels of DPPIV/CD26 were expressed in follicular and papillary thyroid carcinomas than in undifferentiated anaplastic thyroid carcinomas [23]. The gene discussed is DPP4; the disease is thyroid gland papillary carcinoma.