ABSTRACT
BACKGROUND AND OBJECTIVES: Raman spectroscopy is a vibrational spectroscopic technique capable of providing details on the chemical composition, molecular structure and molecular interactions in cells and tissues. Its application of distinguishing normal and cancer tissue has been studied in a variety of sites, such as the cervix, lung, larynx and skin. The purpose was to explore spectral changes between normal and cancer tissue in the larynx using Raman spectroscopy to assess the feasibility of using Raman spectroscopy for the early diagnosis of laryngeal cancer. MATERIALS AND METHOD: Laryngeal tissue specimens (13 adjacent normal and 13 cancer tissues) were obtained from patients who underwent total laryngetomy or supracricoid laryngectomy with squamous cell carcinoma of the larynx. The specimens were stored -70 degrees C until use. These specimens were defrosted at room temperature. The Raman spectra from laryngeal tissue specimens could be obtained at 300 mW and 250 scan during 15 minutes of the signal acquisition time using FT-Raman spectroscopy (Bruker Co., Karsruhe, Germany). RESULTS: Raman spectra were different significantly between cancer and adjacent normal tissues of the larynx at 1446 cm-1, 1240 cm-1, 1335 cm-1, and 1655 cm-1 (p=0.007, 0.2, 0.2, 0.3, respectively). The difference of 1446 cm-1 means the change of CH2 bending mode in protein and lipid of malignant tissue. The change of 1335 cm-1 means a decrease in CH3CH2 to a wagging mode of collagen and polynucleotide chain of malignant tissue. The difference of 1240 and 1655 means a decrease in the alpha-helix conformation of collagen. CONCLUSION: This study demonstrates the differences of Raman units between laryngeal cancer and adjacent normal tissue using Raman spectroscopy. In future, Raman spectroscopy may become a useful tool of guided biopsy for accurate pathologic diagnosis and assessment of the adequacy of resection margins.
Subject(s)
Female , Humans , Biopsy , Carcinoma, Squamous Cell , Cervix Uteri , Collagen , Diagnosis , Early Diagnosis , Laryngeal Neoplasms , Laryngectomy , Larynx , Lung , Molecular Structure , Skin , Spectrum Analysis , Spectrum Analysis, RamanABSTRACT
PURPOSE: Raman spectroscopy is a vibrational spectroscopic technique, which is capable of providing details on the chemical composition, molecular structure and molecular interactions in cells and tissues. The primary objective of this study was to explore Raman spectroscopy for the detection of spectral changes between normal and cancer tissue in the stomach. METHODS: Tissue specimens were obtained from the resected stomach of advanced gastric cancer patients. The normal gastric and cancer tissues were harvested from the middle, lower portion of the stomach and from the tumor mass, respectively. 19 sets (antrum, body and cancer) of spectral data, with clearly defined histopathological findings, were selected in this study. FT-Raman spectroscopy (Bruker Inc., Karsruhe, Germany) was used for tissue Raman studies, with excitation at 1, 064 nm. The Raman spectra from the gastric tissue specimens were obtained with a 20 minute signal acquisition time. RESULTS: In the range 700~1, 900 cm-1, the Raman spectra of gastric antral tissue were dominated by a number of vibrational modes of biomolecules, such as proteins, lipids and nucleic acids. The Raman spectrum pattern of gastric body tissue was similar to that of the antrum, suggesting the structure and composition between the gastric antrum and body are much the same. The Raman spectra differed significantly between the normal and malignant cancer tissues, with cancers showing higher percentage signals for protein, lipid and nucleic acid compared to normal tissue (P<0.05). Difference were observed in the shapes of the Raman spectra between the normal and cancer tissues, particularly in the spectral ranges 1, 250~1, 255, 1, 330~1, 340 and 1, 440~1, 450 cm-1, which contain signals relating to protein and lipid conformations and CH2 bending mode of nucleic acids. CONCLUSION: This study demonstrates the ability of Raman spectroscopy to detect biochemical changes in malignant gastric tissue, and may become a useful adjunct to pathological diagnosis allowing guided biopsies and assessment of adequacy of resection margins.