EPCAM and cancer: The last term on the RHS of Eq (3) is the first step of the branching process relative to the expression of cell membrane proteins favouring the formation of metastasis, and it describes the intravasation of cancer cells in the nearest blood vessels occurring at rate rint with probability Γ(CEPC), where CEPC indicates the EPCAM gene expression level (see Methods section and Branching process and survival probability prediction subsection).