New blood biopsy technique gives UM researchers genetic analysis of cancer cells
Ann Arbor — University of Michigan researchers have found a new way to cleanly separate out cancer cells from blood samples, which could help doctors target tumors and monitor treatments, according to a new study.
The new technique, which researchers call Hydro-Seq, uses a microfluidic chip designed to catch circulating tumor cells.
It allows comprehensive genetic profiling of the cancer cells and is "a dramatic improvement over current approaches," because it encompasses the variation among cancer cells within a single patient, officials said.
"This could be a whole different ball game," said Max Wicha, the Madeline and Sidney Forbes Professor of Oncology at UM.
Earlier techniques only allowed researchers to gather information on the cancer cell's genetic profile or capture most of the cancer cells and only being able to look for a few genes. By choosing, genetic profiles often neglected important cells believed to spread cancer in the body, according to the university.
“Our chip allows us to capture pure circulating tumor cells and then extract genetic information without any contamination from red and white blood cells,” said Euisik Yoon, UM professor of electrical engineering and computer science and senior author on the study.
Some modern cancer drugs work by attacking cells with certain genes in play, but genes with cancer cells aren’t always uniformly shown in the patient and can change over the course of treatment, officials said.
Wicha said it was important to find a solution because repeating biopsies to monitor tumors are painful and potentially dangerous for the patient. Using the chip to capture cancer cells from blood samples offers a noninvasive way to observe whether the cancer is disappearing or if it is becoming resistant to the treatment.
“It allows you not only to select targeted therapies but to monitor the effects of these therapies in patients by doing this blood test,” Wicha said.
The team studied 666 cancer cells from the blood of 21 breast cancer patients through the new method. They found that even within a single patient cancer cells often behave differently.
Wicha’s group began on the study following their previous work studying stem cells effects on cancer metastasis.
They found that cancer stem cells make up a small percent of tumor’s cells, but they make up a higher proportion of cancer cells in the bloodstream. During their study, about 30-50% of the cancer cells captured from the blood samples displayed stem-like properties.
The study led them to the new lab-on-a-chip discovery to narrow down the genetic makeup of cancer from the blood.
Hydro-Seq filters through blood cells and analyzes each cancer cell through channels and chambers in the microchip that's just bigger than a penny.
The team went after the cells’ “transcriptomes”— basically, snapshots of what DNA being used by each cell, revealing the cells’ active genes.
“Before, we could measure two or three genes at a time with staining methods, but now we get a comprehensive picture of circulating tumor cells by measuring thousands of genes in each cell at once,” said Yu-Chih Chen, UM assistant research scientist in electrical engineering and computer science and co-first author on the study.