▁interesting ▁fact ▁indicating ▁that ▁the ▁p 2 7 ▁protein , ▁despite ▁a ▁great ▁variety ▁of ▁functions , ▁plays ▁an ▁important ▁role ▁in ▁the ▁control ▁of ▁cell ▁mot ility . ▁In ▁particular , ▁a ▁lack ▁of ▁this ▁protein ▁under ▁in ▁vit ro ▁conditions ▁indu ces ▁the ▁mes en ch ym al - amo eb oid ▁transition ▁in ▁cells ▁in ▁a ▁ 3 D ▁matrix . <0x09> ▁ <0x09> ▁Some ▁authors ▁studying ▁the ▁mechan isms ▁of ▁invas ive ▁growth ▁upon ▁individual ▁cell ▁migration ▁indicate ▁the ▁possibility ▁of ▁an ▁am o eb oid - mes en ch ym al ▁transition ▁that ▁is ▁the ▁reverse ▁process ▁to ▁the ▁mes en ch ym al amo eb oid ▁transition . ▁There ▁is ▁a ▁hypothesis ▁according ▁to ▁which ▁the ▁mechanism ▁of ▁am o eb oid - mes en ch ym al ▁transition ▁most ▁likely ▁re lies ▁on ▁the ▁same ▁mole cular ▁basis , ▁and ▁that ▁the ▁only ▁reliable ▁process ▁that ▁determ ines ▁the ▁possibility ▁of ▁the ▁described ▁transformation ▁is ▁an ▁im bal ance ▁in ▁the ▁activity ▁of ▁members ▁of ▁the ▁small ▁G TP ase ▁family ▁and ▁pre domin ance ▁of ▁the ▁R ac ▁activity ▁over ▁the ▁R ho A ▁activity . ▁The ▁mechan isms ▁that ▁could ▁under lie ▁the ▁described ▁changes ▁remain ▁unclear . ▁ ▁Collect ive - ind ividual ▁trans itions ▁T um or ▁cells ▁within ▁a ▁single ▁tum or ▁can ▁simultaneously ▁move ▁both ▁collect ively ▁and ▁individually . ▁In ▁this ▁case , ▁the ▁transition ▁from ▁individual ▁to ▁collect ive ▁migration ▁is ▁an ▁important ▁step ▁towards ▁increasing ▁the ▁invas