▁The ▁possibility ▁to ▁retain ▁the ▁rapid ▁and ▁non - f ocal ▁assembly ▁of ▁re cept ors ▁at ▁the ▁sites ▁of ▁cell ▁contacts ▁with ▁the ▁ext rac ell ular ▁substr ate ▁has ▁been ▁noted . ▁Integr ins ▁are ▁not ▁important ▁in ▁this ▁type ▁of ▁invas ive ▁growth . ▁Import ant ▁aspects ▁are ▁the ▁absence ▁of ▁prote ol ysis ▁at ▁the ▁sites ▁of ▁cell - matrix ▁interactions ▁and ▁the ▁lack ▁of ▁expression ▁of ▁prote ol yt ic ▁en zym es ▁that ▁destroy ▁the ▁ext rac ell ular ▁matrix . ▁In ▁vit ro ▁studies ▁have ▁demonstrated ▁that , ▁in ▁the ▁case ▁of ▁an ▁am o eb oid ▁type ▁of ▁invas ive ▁growth , ▁it ▁is ▁likely ▁due ▁to ▁these ▁properties ▁that ▁tum or ▁cells ▁are ▁capable ▁of ▁moving ▁at ▁the ▁highest ▁speed ▁in ▁cult ures ▁( 2 0 ▁ μ m / min ). <0x09> ▁ <0x09> ▁Am o eb oid - mes en ch ym al ▁and ▁mes en ch ym al - amo eb oid ▁trans itions <0x09> ▁ <0x09> ▁We ▁have ▁already ▁noted ▁the ▁existence ▁of ▁a ▁degree ▁of ▁pl astic ity ▁and ▁the ▁possibility ▁of ▁a ▁“ shift ” ▁from ▁one ▁migration ▁type ▁to ▁the ▁other ▁( from ▁the ▁mes en ch ym al ▁type ▁to ▁the ▁am o eb oid ▁one ▁and ▁vice ▁vers a ) ▁upon ▁individual ▁cell ▁invasion . ▁These ▁events ▁are ▁apparently ▁due ▁to ▁the ▁appearance ▁of ▁changes ▁in ▁the ▁activity ▁of ▁certain ▁cell ▁mole cules ▁and ▁the ▁need ▁to ▁adapt ▁to ▁t issue ▁micro environment ▁conditions ▁(