▁inter cell ular ▁contacts . ▁During ▁car cin ogen esis , ▁ep ith el ial ▁cells ▁are ▁subject ed ▁to ▁a ▁morph ological ▁transformation ▁that ▁is ▁phen ot yp ically ▁similar ▁to ▁E MT ▁but ▁develop s ▁in ▁the ▁absence ▁of ▁the ▁relevant ▁H G F ▁lig and . ▁This ▁transformation ▁in ▁m align ant ▁tum ors ▁can ▁be ▁induced ▁by ▁trans fection ▁of ▁various ▁on c ogen es . ▁During ▁transformation , ▁tum or ▁cells ▁can ▁leave ▁the ▁ep ith el ial ▁layer ▁and ▁move ▁like ▁fib ro bl asts , ▁thereby ▁gain ing ▁the ▁ability ▁of ▁invasion ▁and ▁met ast asis . <0x09> ▁ <0x09> ▁During ▁E MT , ▁the ▁following ▁major ▁events ▁occur : ▁m align ant ▁ep ith el ial ▁cells ▁lose ▁their ▁ap ical - bas al ▁polar ity ▁due ▁to ▁dis ruption ▁in ▁tight ▁inter cell ular ▁j unction s ▁and ▁loss ▁of ▁cell ular ▁ad hes ion ▁mole cules ▁( such ▁as ▁E - c ad her in ▁and ▁integr ins ); ▁the ▁cell ular ▁act in ▁c yt os ke leton ▁is ▁changed ▁and ▁subject ed ▁to ▁rem od eling ▁with ▁the ▁formation ▁of ▁stress ▁fib ers ▁that ▁are ▁collected ▁in ▁certain ▁cell ▁parts ▁near ▁the ▁cell ▁memb rane , ▁where ▁specific ▁cell ular ▁pro tr us ions ▁begin ▁subsequently ▁to ▁form ; ▁de grad ation ▁of ▁the ▁underlying ▁bas al ▁memb rane ▁of ▁the ▁ep ith el ium ▁occurs , ▁which ▁results ▁in ▁the ▁fact ▁that ▁tum or ▁cells ▁lack ing ▁inter cell ular