Media Releases

Sorting bloodborne cancer cells to better predict spread of disease

November 6, 2014

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.”

-30-

Media Con­tact:

Jef Ekins
Man­ag­er, Mar­ket­ing & Com­mu­ni­ca­tions
Leslie Dan Fac­ul­ty of Phar­ma­cy
Uni­ver­si­ty of Toron­to
416–946-7036
j.ekins@utoronto.ca