**8.3 Kai1**

Kangai 1 (from Chinese kang ai meaning anticancer) or Kai1 is a member of the Transmembrane-4 superfamily of adhesion molecules and is involved in lymphocyte differentiation and function. It was originally described as a metastasis suppressor in prostate cancer but its role has been established as a general suppressor of the metastatic phenotype in many cancer types including breast cancer, although KAI1 does not affect primary tumor growth (52).
