▁as ▁well ▁as ▁determ ination ▁of ▁I G F - 1 R , ▁Her 2 , ▁B cl - 2 , ▁ER G , ▁P T EN , ▁AR ▁status ▁using ▁imm un of lu ores c ence . ▁Single ▁cell ▁level ▁q PC R ▁can ▁also ▁be ▁performed ▁with ▁the ▁C TC s ▁isolated ▁from ▁blood . ▁ ▁The ▁organ ▁trop ism ▁of ▁patient - der ived ▁C TC ▁has ▁been ▁investig ated ▁in ▁a ▁mouse ▁model . ▁C TC s ▁isolated ▁from ▁breast ▁cancer ▁patients ▁and ▁expanded ▁in ▁vit ro ▁showed ▁they ▁could ▁generate ▁b one , ▁lung , ▁ov ary ▁and ▁brain ▁met ast ases ▁in ▁m ice , ▁partially ▁reflect ing ▁the ▁secondary ▁les ions ▁as ▁found ▁in ▁the ▁corresponding ▁patients . ▁Rem ark ably , ▁one ▁C TC ▁line — is ol ated ▁long ▁before ▁the ▁appearance ▁of ▁brain ▁met ast asis ▁in ▁patient — was ▁highly ▁compet ent ▁to ▁generate ▁brain ▁met ast asis ▁in ▁m ice . ▁This ▁was ▁the ▁first ▁predict ive ▁case ▁for ▁brain ▁met ast asis ▁and ▁a ▁proof ▁of ▁concept ▁that ▁intr insic ▁mole cular ▁features ▁of ▁met ast atic ▁prec urs ors ▁amongst ▁C TC s ▁could ▁provide ▁novel ▁ins ights ▁into ▁the ▁mechan isms ▁of ▁met ast asis . ▁ ▁Cell ▁morph ology ▁Mor ph ological ▁appearance ▁is ▁jud ged ▁by ▁human ▁operators ▁and ▁is ▁therefore ▁subject ▁to ▁large ▁inter ▁operator ▁variation . ▁Several ▁C TC ▁enumer ation ▁methods ▁exist ▁which ▁use ▁morph ological ▁appearance ▁to ▁identify ▁C TC ,