AsianScientist (Oct. 10, 2017) – In a study published in Scientific Reports, scientists in Japan report a rapid and non-invasive method to diagnose colorectal cancer.
To diagnose cancer and determine the appropriate treatment, pathologists depend on biopsies from the patient. The cutting, fixing and staining of the specimen generally provides reliable information, but these pathology-based diagnostic procedures require substantial time and cause tissue damage.
In this study, a team of scientist at Osaka University, led by Professor Masaru Ishii, have developed a method for quantitative imaging of cancer that is safe and requires no resection, fixation or staining of tissues. They called their method non-labeling multiphoton excitation microscopy (NL-MPM).
“MPM relies on second harmonic generation (SHG) in addition to autofluorescence, and the basement membrane beneath the epithelial cells gives a strong SHG signal,” Ishii explained, adding that the signal comes specifically from the basement membrane of the tissue, a region that is difficult to observe using contemporary staining techniques.
The researchers applied their method to colorectal cancer, which particularly affects epithelial tissue. Thus, colorectal tumors emanate a sufficient signal in NL-MPM without the addition of any foreign dye, since chemicals natural to the tissue will emit autofluorescence.
They were able to quantify the severity of the cancer using two parameters they created, index N and index S. Index N is a number that describes the size of the nuclei in the cell, while index S is a number that summarizes the intensity of SHG signals. Normal tissue was defined as that with an index N 9.5 (a larger index N indicating larger nuclei) and an index S > 3.1 (healthy tissue, because of its regular structure, gives off a stronger SHG signal). The two indices provided a highly reliable prediction of the malignancy of the cancer.
“Any tissues that were outside these boundaries were deemed cancerous,” said Ishii.
Ishii acknowledged that the technology needs improvement before it reaches clinical use, but he was excited about its prospect for patient care.
“We envision the use of endoscopy with the MPM system, as well as the use of NL-MPM during operations because of its rapid analysis,” he said.
The article can be found at: Matsui et al. (2017) Non-labeling Multiphoton Excitation Microscopy as a Novel Diagnostic Tool for Discriminating Normal Tissue and Colorectal Cancer Lesions.
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Source: Osaka University; Photo: Shutterstock.
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