▁results ▁were ▁made ▁possible ▁by ▁ex quis it ely ▁sensitive ▁magnetic ▁separation ▁technology ▁employ ing ▁ferro flu ids ▁( col lo idal ▁magnetic ▁nan op articles ) ▁and ▁high ▁gradient ▁magnetic ▁separ ators ▁invent ed ▁by ▁Paul ▁Liber ti ▁and ▁motiv ated ▁by ▁theoretical ▁calculations ▁by ▁Liber ti ▁and ▁Leon ▁Ter st appen ▁that ▁indicated ▁very ▁small ▁tum ors ▁shed ding ▁cells ▁at ▁less ▁than ▁ 1 . 0 % ▁per ▁day ▁should ▁result ▁in ▁detect able ▁cells ▁in ▁blood . ▁A ▁variety ▁of ▁other ▁techn ologies ▁have ▁been ▁applied ▁to ▁C TC ▁enumer ation ▁and ▁identification ▁since ▁that ▁time . ▁ ▁Modern ▁cancer ▁research ▁has ▁demonstrated ▁that ▁C TC s ▁derive ▁from ▁cl ones ▁in ▁the ▁primary ▁tum or , ▁valid ating ▁Ash worth ' s ▁remarks . ▁ ▁The ▁significant ▁efforts ▁put ▁into ▁understanding ▁the ▁C TC s ▁bi ological ▁properties ▁have ▁demonstrated ▁the ▁ ▁critical ▁role ▁circul ating ▁tum or ▁cells ▁play ▁in ▁the ▁met ast atic ▁spread ▁of ▁car cin oma . ▁Furthermore , ▁highly ▁sensitive , ▁single - cell ▁analysis ▁demonstrated ▁a ▁high ▁level ▁of ▁heter ogene ity ▁seen ▁at ▁the ▁single ▁cell ▁level ▁for ▁both ▁protein ▁expression ▁and ▁protein ▁local ization ▁ ▁and ▁the ▁C TC s ▁reflected ▁both ▁the ▁primary ▁bi ops y ▁and ▁the ▁changes ▁seen ▁in ▁the ▁met ast atic ▁sites . ▁ ▁References ▁▁ ▁Category : An atom ical ▁path ology ▁Category : On col ogy <0x0A> </s> ▁The ▁B alk an ▁P act ▁of ▁ 1 9 5 3 , ▁officially ▁known