▁to ▁under lie ▁the ▁processes ▁of ▁emb ry ogen esis ▁and ▁infl amm ation ▁and ▁reg ener ation ▁of ▁t issues ▁and , ▁certainly , ▁plays ▁a ▁key ▁role ▁in ▁the ▁mechan isms ▁of ▁car cin ogen esis . ▁ ▁Phys i ological ▁pro tot ypes ▁of ▁invas ive ▁growth ▁T um or ▁cells ▁spread ing ▁into ▁the ▁surrounding ▁t issues ▁and ▁distant ▁org ans ▁are ▁known ▁to ▁reproduce ▁the ▁mechan isms ▁and ▁migration ▁types ▁characteristic ▁of ▁normal , ▁non - t um or ▁cells ▁during ▁phys i ological ▁processes . ▁T um or ▁cells , ▁similar ▁to ▁normal ▁cells , ▁are ▁capable ▁of ▁activ ating ▁these ▁mechan isms ▁for ▁changing ▁their ▁own ▁shape , ▁creating ▁conditions ▁for ▁moving , ▁as ▁well ▁as ▁rem od eling ▁surrounding ▁t issues ▁to ▁form ▁migration ▁path ways . ▁The ▁main ▁problem ▁is ▁that ▁tum or ▁cells , ▁in ▁contrast ▁to ▁normal ▁cells , ▁do ▁not ▁have ▁phys i ological ▁“ stop ▁signals ” ▁to ▁terminate ▁these ▁processes . ▁Most ▁likely , ▁this ▁leads ▁to ▁the ▁establishment ▁of ▁the ▁migration ▁mechan isms ▁and ▁prom otes ▁the ▁pro gression ▁and ▁spread ▁of ▁the ▁tum or . <0x09> ▁ <0x09> ▁M align ant ▁cells ▁were ▁found ▁to ▁use ▁built - in ▁gen etic ▁programs ▁to ▁implement ▁the ▁processes ▁that ▁determine ▁invas ive ▁growth ▁and ▁the ▁possibility ▁of ▁met ast asis . ▁For ▁example , ▁the ▁movement ▁of ▁a ▁single ▁cell ▁is ▁observed ▁during ▁emb ry onic ▁development ▁and ▁infl amm ation ▁( e . g ., ▁le uk ocy