▁task . ▁Unfortunately , ▁studies ▁exam ining ▁this ▁issue ▁at ▁the ▁mole cular ▁and ▁morph ological ▁levels ▁are ▁few ▁in ▁numbers ▁and ▁mostly ▁were ▁carried ▁out ▁in ▁vit ro ▁using ▁specific ▁cell ▁lines . <0x09> ▁ <0x09> ▁However , ▁now , ▁there ▁is ▁considerable ▁increase ▁in ▁the ▁number ▁of ▁studies ▁that ▁demonstrate ▁increasing ▁interest ▁in ▁research ▁into ▁the ▁mole cular ▁gen etic ▁features ▁of ▁tum or ▁cells ▁that ▁determine ▁the ▁main ▁differences ▁between ▁the ▁mes en ch ym al ▁and ▁am o eb oid ▁types ▁of ▁cell ▁movement ▁during ▁individual ▁migration , ▁as ▁well ▁as ▁collect ive ▁migration . <0x09> ▁ <0x09> ▁Collect ive ▁migration <0x09> ▁ <0x09> ▁Collect ive ▁migration ▁is ▁character ized ▁by ▁the ▁migration ▁of ▁whole ▁groups ▁of ▁cells ▁inter connected ▁by ▁ad hes ion ▁mole cules ▁and ▁other ▁communication ▁j unction s ▁( Fig . ▁ 1 ). ▁This ▁is ▁the ▁main ▁feature ▁of ▁this ▁type ▁of ▁invasion , ▁since ▁the ▁underlying ▁cell ular ▁mechan isms ▁are ▁the ▁same ▁key ▁processes ▁that ▁largely ▁determine ▁single ▁cell ▁migration . <0x09> ▁ <0x09> ▁Collect ive ▁cell ▁migration ▁has ▁been ▁observed ▁in ▁the ▁development ▁and ▁pro gression ▁of ▁breast ▁and ▁end omet rial ▁cancer , ▁pro state ▁cancer , ▁col ore ct al ▁cancer , ▁large cell ▁lung ▁car cin oma , ▁r hab dom y os ar com a , ▁mel an oma , ▁as ▁well ▁as ▁most ▁squ am ous ▁cell ▁car cin omas . <0x09> ▁ <0x09> ▁In ▁the ▁case ▁of ▁collect ive ▁migration , ▁cancer ▁cells , ▁being