▁contacts ▁become ▁capable ▁of ▁invas ive ▁growth ▁and ▁pen etr ation ▁into ▁the ▁surrounding ▁st rom al ▁matrix ▁and ▁begin ▁active ▁migration . <0x09> ▁ <0x09> ▁E MT ▁was ▁found ▁to ▁be ▁rarely ▁equally ▁pron ounced ▁in ▁the ▁entire ▁tum or ▁t issue . ▁More ▁likely , ▁this ▁process ▁is ▁character ized ▁by ▁a ▁varying ▁intensity ▁of ▁the ▁transition ▁of ▁cells ▁from ▁the ▁ep ith el ial ▁to ▁the ▁mes en ch ym al ▁phen ot ype . ▁In ▁this ▁regard , ▁some ▁research ers ▁describe ▁the ▁so - called ▁partial ▁E MT , ▁in ▁which ▁most ▁cells ▁in ▁the ▁invas ive ▁front ▁are ▁involved ▁( Fig . ▁ 1 ). ▁Part ial ▁E MT ▁is ▁a ▁state ▁when ▁cells ▁have ▁already ▁gained ▁the ▁properties ▁necessary ▁for ▁successful ▁migration , ▁but ▁continue ▁to ▁retain ▁cell - cell ▁contacts . ▁This ▁phen ot ype ▁was ▁called ▁the ▁hy brid ▁“ ep ith el ial - ▁mes en ch ym al ” ▁phen ot ype ▁and ▁was ▁linked ▁to ▁the ▁features ▁characteristic ▁of ▁collect ively ▁moving ▁tum or ▁cells . <0x09> ▁ <0x09> ▁T ad de i ▁et ▁al . ▁have ▁indicated ▁that ▁E MT ▁develop s ▁due ▁to ▁the ▁induction ▁of ▁programs ▁associated ▁with ▁the ▁activation ▁of ▁key ▁trans cription ▁factors , ▁such ▁as ▁T W IST 1 , ▁Sn ail , ▁Sl ug , ▁and ▁Z EB 1 / 2 . ▁This ▁results ▁in ▁dis ruption ▁in ▁strong ▁cad her in ▁j unction s ▁and ▁activation ▁of ▁polar ▁cell ▁migration ▁and ▁prote ol