▁tum ors ▁in ▁v ivo . ▁A ▁relationship ▁between ▁the ▁application ▁of ▁dru gs ▁on ▁the ▁basis ▁of ▁matrix ▁metal lo prote in ase ▁in hib itors ▁in ▁cancer ▁ther apy ▁and ▁pro gression ▁of ▁the ▁tum or ▁process ▁was ▁established . ▁The ▁explanation ▁of ▁this ▁relationship ▁became ▁possible ▁only ▁after ▁the ▁identification ▁of ▁tum or ▁cells ▁capable ▁of ▁am o eb oid ▁migration . ▁These ▁data ▁most ▁likely ▁indicate ▁that , ▁under ▁conditions ▁of ▁a ▁reduction ▁in ▁or ▁complete ▁loss ▁of ▁their ▁ability ▁to ▁spread ▁to ▁the ▁surrounding ▁t issues ▁using ▁the ▁main ▁mole cules ▁that ▁perform ▁ad hes ion ▁and ▁destruction ▁of ▁the ▁ext rac ell ular ▁matrix , ▁tum or ▁cells ▁turn ▁to ▁the ▁am o eb oid ▁mechanism ▁of ▁invasion , ▁which ▁becomes ▁the ▁only ▁and ▁most ▁effective ▁mode ▁of ▁migration . <0x09> ▁ <0x09> ▁This ▁type ▁of ▁migration ▁has ▁been ▁described ▁in ▁circul ating ▁stem ▁cells , ▁le uk ocy tes , ▁and ▁certain ▁types ▁of ▁tum or ▁cells . ▁According ▁to ▁Z ij l ▁et ▁al ., ▁the ▁am o eb oid ▁type ▁of ▁invas ive ▁growth ▁has ▁been ▁observed ▁in ▁breast ▁cancer , ▁l ym ph oma , ▁small ▁cell ▁lung ▁cancer ▁and ▁pro state ▁cancer , ▁and ▁mel an oma . <0x09> ▁ <0x09> ▁In ▁the ▁case ▁of ▁am o eb oid ▁migration , ▁m align ant ▁tum or ▁cells ▁have ▁been ▁demonstrated ▁to ▁have ▁a ▁round ▁or ▁elli pt ical ▁shape ▁( Fig . ▁ 1 ). ▁Am o eb oid ▁cells ▁are ▁character