According to a recent study, a new method for the complete isolation of cancer cells from blood samples provides a comprehensive genetic analysis of cancer cells, helping doctors to target tumors more effectively and monitor treatments.

Early techniques could only perform a full genetic profile in a limited subset of cancer cells, or capture most cancer cells but only look for changes in some genes. Therefore, the genetic spectrum usually ignores important cancer cell populations.

'Our chips capture pure circulating tumor cells and then extract genetic information without any contamination by red blood cells and white blood cells,' said Euisik Yoon, a senior author of the study, professor of electrical engineering and computer science at U-M.

Many modern anticancer drugs work by tracking cells with certain genes - these genes mark their identity as cancer cells. However, these genes are not evenly active in the patient's cancer cell population and can change during the course of treatment.

Repeated biopsies to monitor tumors are painful and potentially dangerous to the patient. Capturing cancer cells from blood samples provides a non-invasive method to see if the cancer has disappeared or is resistant to treatment.

'It not only allows you to choose targeted therapies, but also monitors the impact of these therapies on patients through blood tests,' the authors said.

Using this approach, the team collected and analyzed 666 cancer cells from the blood of 21 breast cancer patients. Genetic analysis confirms that cancer cells usually behave very differently even in a single patient. Wicha's team has previously shown that cancer metastasis is mediated by cancer cells with stem cell properties. Although cancer stem cells account for only a few percent of tumor cells, they constitute a higher proportion of cancer cells in the blood. In this study, approximately 30-50% of cancer cells captured from blood samples showed stem cell-like properties.

The technique of capturing clean but incomplete cancer cell samples from the patient's blood by grasping the proteins on the cell surface is particularly easy to miss. Stem-like cells are located between two more typical cell types, which means they do not display consistent protein markers.

“Before, we could measure two to three genes at once using the staining method, but now we can fully understand circulating tumor cells by measuring thousands of genes per cell at a time,” said UM assistant research scientist Yu-Chih Chen. The study was published in the journal Nature Communications.

Information source: Blood biopsy: New technique enables detailed genetic analysis of cancer cells