For the past 20 years, many of the dramatic improvements in cancer outcomes can be attributed to personalized cancer treatments based upon DNA mutations in a tumor. Targeted therapies — often one pill a day — can stop the spread of cancer and shrink tumors.
The problem? Cancer cells often find ways to evade or survive, despite the presence of drugs designed to attack them. This “resistance” often means that cancer treatment needs to be changed.
“From the patient point of view, that’s incredibly frustrating,” said Dr. Tim Cannon, medical oncologist and clinical director of the weekly molecular tumor board at Inova Schar Cancer Institute in Fairfax, Virginia.
The tumor board, made up of cancer research and treatment specialists, matches patients with targeted therapies based on molecular diagnostics.
“They (patients) will often have this new targeted therapy that works very well for the first three or six months that they get it, and then it will suddenly stop working,” Cannon said.
“When a treatment stops working, we always want to know why — what changed in the cell to make it resistant to our treatment.”
Next-generation cancer treatment is using proteomics, which identifies proteins driving tumor growth, and can show how cancer cells are changing in response to therapy.
“With proteomics, you can see what proteins are actually expressed and active in a cell, and they may be a better way to predict what treatments are going to help,” Cannon said.
Inova said it’s the first health system in the U.S. using real-time analysis of proteomics (pronounced pro-tee-OH-micks) in its weekly tumor boards.
How biomarker testing and proteomics can work together
Cancer is often diagnosed through a tissue biopsy.
Current biomarker testing often involves analysis of tissue taken during that biopsy. The testing looks to determine if the tumor has “actionable” mutations, which can be treated with a targeted therapy — often a daily pill — which zooms in on cancer cells, and spares healthy cells, unlike chemotherapy.
(I was diagnosed with stage 4 EGFR-positive lung cancer in November 2022 by doctors at Inova Schar. After a few months of targeted therapy and a lobectomy, I’ve been cancer-free since May 2023, while continuing my one-pill-a-day regimen)
For a patient who has a tumor surgically removed, or a patient whose other treatments have left them with “no evidence of disease,” or NED, a periodic liquid biopsy — a blood draw — can help determine if there are any cancer cells still circulating in a patient’s bloodstream.
“DNA is excellent for that purpose, seeing if there’s tumor left in the body,” Cannon said. “What proteomics may be able to do better than DNA is to predict before you get treatment whether or not it will work.”
As for how the proteomics analysis is done, a computerized laser cuts and collects cancer cells from the tumor. In a second process, antibodies are used to detect and measure specific proteins, Cannon said.
“It’s just like cracking open a cell and looking inside,” Cannon said. “Not just at the DNA, but what’s happening in the cell.”
According to Schar, recent studies show proteomic analysis take an average of nine days to be completed, which gives oncologists time to refer patients for any further testing, and determine future treatment plans.
