Cancer-Detecting Pen May Improve Tumor Removal
The diagnostic tool extracts molecules from tissue and performs mass spectrometry analysis in 10 seconds.
Vivian Abagiu/Univ. of Texas at Austin
A handheld, pen-sized device uses a water droplet and mass spectrometry to enable fast and accurate molecular identification of human cancer tissues, according to a recent study. The device, named MasSpec Pen, exposes a tissue surface to a single drop of water for three seconds, allowing for efficient extraction of a variety of potential cancer biomarkers such as metabolites, lipids and proteins, which are then transported to a mass spectrometer for molecular analysis. As reported September 6 in Science Translational Medicine, the process does not destroy tissues and is completed in 10 seconds or less, potentially enabling near real-time cancer diagnosis suitable for routine clinical use.
“This study represents the best effort to date to create a way to use mass spectrometry to guide surgery,” said Daniel Orringer, assistant professor of neurological surgery at the University of Michigan, who was not involved in the study. “If the probe developed here applies to a human surgical environment, it could replace the need for current methods for diagnosis during surgery. It could also provide assurance that clean margins have been achieved during tumor removal. The handheld system demonstrated here could be useful for helping surgeons to achieve more accurate results during cancer surgery in the future.”
Cancer surgeries that completely remove tumors offer patients the best chance of prolonged survival. However, conventional methods for histopathologic tissue analysis are labor-intensive and time-consuming, and can delay decision-making during diagnostic and therapeutic procedures. Frozen section analysis during surgery takes approximately 30 minutes, while postoperative final pathologic evaluation lasts several days. These delays can potentially prolong operation times, subject the patient to increased risks related to extended anesthesia or additional surgical procedures, and increase health care costs.
Analyzing specific molecules in tissues offers a potentially improved way to detect and diagnose cancer in a clinical setting. “Analyzing cancer and normal tissue by mass spectrometry has shown promising results in the last few years. But traditional mass spectrometry uses high voltages and harmful solvents that are potentially damaging to living tissue,” said study author John Lin of the University of Texas at Austin. “The motivation for the MasSpec Pen study was to apply the powerful analytical technique of mass spectrometry into a tool that is biocompatible and clinically useful in real time.”
To meet this goal, senior author Livia Eberlin and her team at the University of Texas at Austin designed an automated handheld mass spectrometry device for rapid and nondestructive diagnosis of human cancer tissues. They used the MasSpec Pen for molecular analysis of 20 human cancer thin tissue sections and 253 human patient tissue samples from the breast, lung, thyroid and ovary. When the researchers statistically analyzed the results, they found they could achieve cancer prediction with an overall accuracy of 96 percent, as well as prediction of benign and malignant thyroid tumors and different histologic subtypes of lung cancer.
“It’s so simple,” said Pieter Dorrestein, director of the Collaborative Mass Spectrometry Innovation Center at the University of California, San Diego, who was not involved in the study. “It’s basically a small water spray and then a suction device that looks like a pen attached to a chemical recorder—a mass spectrometer that is a fancy scale capable of weighing molecules. Then they can use the chemical information to train algorithms to recognize cancer versus non-cancer tissues.”
Notably, the results showed that the molecular information obtained by the MasSpec Pen can be used to detect cancer in marginal tumor regions with mixed composition of normal and cancer cells. The authors also demonstrated that the MasSpec Pen is suited for identifying cancerous tissue during surgery performed on mice with tumors. The researchers plan to start testing the device in surgeries for cancer patients early next year.
“The MasSpec Pen has the potential to directly help a surgeon decide whether the cancerous tissue is removed and does not interfere with current standard procedures,” Dorrestein said, adding that it could lower the need for additional surgeries or reduce common complications such as infections. “Cancer is one application, but one can envision applying the MasSpec pen as a general screen in a primary care doctor’s office for urine sampling, saliva sampling and much more, and for many indications ranging from immunological disorders to infectious disease.”