Media Releases

Sorting bloodborne cancer cells to better predict spread of disease

November 6, 2014

University of Toronto researchers develop diagnostic tool to investigate travelling cancer cells and improve health outcomes

TORONTO, ON – For most can­cer patients, pri­ma­ry tumours are often not the most dead­ly. Instead, it is the metasta­t­ic tumours – tumours that spread from their orig­i­nal loca­tion to oth­er parts of the body – that are the cause of most can­cer deaths.

The cat­a­lysts behind the for­ma­tion of these dead­ly metasta­t­ic tumours are believed to be can­cer cells that are launched into the blood­stream from the orig­i­nal site of the can­cer. Researchers are very inter­est­ed in lever­ag­ing these cir­cu­lat­ing tumour cells, or CTCs, which have the poten­tial to allow the prop­er­ties of a tumour to be bet­ter under­stood with­out a biop­sy, and may also help physi­cians rec­og­nize how aggres­sive a tumour is and whether it is like­ly to cause metasta­t­ic dis­ease.

How­ev­er, not all CTCs in a giv­en patient are alike. Recent dis­cov­er­ies have shown that CTCs are high­ly het­ero­ge­neous – with indi­vid­ual can­cer cells pos­sess­ing very dif­fer­ent mol­e­c­u­lar char­ac­ter­is­tics – and that only a small sub­set of these cells actu­al­ly pos­sess the metasta­t­ic poten­tial to spread the dis­ease through­out the body.

Cur­rent tech­nolo­gies exist that allow these cir­cu­lat­ing cells to be cap­tured from the blood of can­cer patients, but they are not well equipped to dif­fer­en­ti­ate between the var­i­ous CTCs present in the blood sam­ple. Instead, they sim­ply count the num­ber of CTCs in a patient sam­ple, rather than iden­ti­fy­ing the cells that pos­sess the high­est metasta­t­ic poten­tial. As a result, these tools are less than ide­al as they are only able to pro­vide gen­er­al infor­ma­tion on the lev­els of CTCs rather than a more focused under­stand­ing of the dis­ease and its aggres­sive­ness.

Researchers at the Leslie Dan Fac­ul­ty of Phar­ma­cy at the Uni­ver­si­ty of Toron­to have devel­oped a new device that pro­vides a way to visu­al­ize the het­ero­gene­ity of CTCs, and have pub­lished their find­ings in the lead­ing Chem­istry jour­nal Ange­wandte Chemie (link). Using nanopar­ti­cles to tag cells, this device sorts the CTCs col­lect­ed in a sam­ple into dis­crete sub­pop­u­la­tions based on the phe­no­type of the cells, and pro­vides a snap­shot of the nature of the tumour cells present in patients’ blood.

“Rec­og­niz­ing that char­ac­ter­iz­ing the phe­no­type of cir­cu­lat­ing tumour cells is more use­ful for can­cer man­age­ment than quan­ti­tat­ing the cells present in a blood sam­ple, we set out to devise a method that would allow us to cap­ture and dis­tin­guish between these cells,” notes Pro­fes­sor Shana Kel­ley of the Leslie Dan Fac­ul­ty of Phar­ma­cy. “In the lab, we were able to demon­strate that the tool was not only high­ly effec­tive at dif­fer­en­ti­at­ing these cells, but also proved to be more sen­si­tive than the cur­rent lead­ing meth­ods of cel­lu­lar sort­ing.”

Part­ner­ing with col­lab­o­ra­tors at the Sun­ny­brook Health Sci­ences Cen­tre and the Lon­don Health Sci­ences Cen­tre, the researchers col­lect­ed sam­ples from prostate can­cer patients to test the effi­ca­cy and abil­i­ty of the diag­nos­tic plat­form.

“Through this study, over 20 patients with local­ized prostate can­cer were test­ed,” notes Dr. Robert Nam, Ajmera Chair in Uro­log­ic Oncol­o­gy and Head of Gen­i­touri­nary Oncol­o­gy, at Sunnybrook’s Odette Can­cer Cen­tre . “Inter­est­ing­ly, sig­nif­i­cant lev­els of these cir­cu­lat­ing tumour cells were observed in all of the patients. Even more intrigu­ing was the obser­va­tion of very dif­fer­ent sub­pop­u­la­tion pro­files across this group of patients that all received very sim­i­lar clin­i­cal diag­noses, indi­cat­ing that mol­e­c­u­lar-­-lev­el dif­fer­ence may exist in the patients’ tumours.”

While this study only involved a small num­ber of patients, fur­ther val­i­da­tion is planned with sev­er­al oth­er can­cers, includ­ing breast, colon, ovar­i­an, lung, and pan­cre­at­ic can­cer.

“Ulti­mate­ly, we believe that this sen­si­tive tech­nol­o­gy pos­sess­es the poten­tial to pro­vide more use­ful infor­ma­tion about these cells, lead­ing to bet­ter diag­noses and improved patient out­comes,” notes Dr. Kel­ley.

“As a result, we are excit­ed to pur­sue new research oppor­tu­ni­ties in an effort to more accu­rate­ly and less inva­sive­ly diag­nose and improve the health out­comes for can­cer patients.”


Media Con­tact:

Jef Ekins
Man­ag­er, Mar­ket­ing & Com­mu­ni­ca­tions
Leslie Dan Fac­ul­ty of Phar­ma­cy
Uni­ver­si­ty of Toron­to