CDH2 and neoplasm: While such a transition from E- to N-cadherin is known from other cell-type changes in embryonal and fetal development as well as from certain pathological transformations as in the invasion and metastasis of diverse kinds of tumor cells (for review, see, e.g., Kalluri and Weinberg 2009), another form of advent of N-cadherin in epithelial cells, i.e., the formation of AJs based on E–N heterodimer clusters, as described for mammalian hepatocytes and liver tumor cells in situ and in culture (Straub et al. 2011), seems to be excluded from the mature and active Sertoli cells.