Researchers at the University of California San Diego have created a microfluidic device which measures how ‘sticky’ cancer cells are and could improve prognostic evaluation of patient tumours.

The device sorts cells by their physical ability to adhere to their environment inside its microfluidic chamber.

Weakly adherent cells were found to migrate into and invade other tissues more than strongly adherent cells from the same tumour. Genes associated with the weakly adherent cells were also associated with an increased likelihood of a patient’s tumour recurring within five years.

The research has been published in Cancer Research.

Historically it has been difficult to find biological markers to universally identify and select the most aggressive cells in tumours. Now, ‘stickiness’ may provide a physical marker of highly metastatic cells within a heterogeneous tumour cell population.

The microfluidic device uses a coating of adhesive protein to trap cancer cells. The cells are placed in the chamber and after they adhere, fluid is pushed through to detach them. The faster the fluid moves, the higher the shear stress that the cells experience. The research team were able to use this process to isolate cells that detach at specific shear stresses and analyse them.

Cells collected at a lower shear stress were weakly adherent while those collected at higher shear stresses were strongly adherent.

Weakly adherent cells were found to have a unique genetic signature that identifies them and causes them to migrate and invade faster. When compared to patient data in the Cancer Genome Atlas (TCGA) database, researchers found that patients with tumours high in this signature experienced tumour recurrence earlier and more frequently. So far, the research team has tested cells from breast, prostate and lung tumours.

The team hopes that future clinicians will be able to use the device to examine tumour biopsies and estimate the chance of metastasis. This way, they’ll be able to adjust treatment at earlier disease stages to maximise positive clinical outcomes.

The researchers are now looking into ‘priming’ tumours in mice with weakly adherent cells to see if they begin to metastasise earlier and more frequently.

University of California San Diego Comprehensive Breast Health Center director Dr Anne Wallace said: “Many cancers that we see in the clinic, such as ductal carcinoma in situ or DCIS, remain dormant for years. It is nearly impossible for us to predict which fraction of that population will reoccur.”

In cases such as these, the microfluidic device could be the first to address and predict these recurrences.