Analysis of Normal and Cancer Tissue in the Stomach Using Raman Spectroscopy

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.

Gastric Cancer Diagnosed in a Patient with Extramammary Paget's Disease

Extramammary Paget's disease (EMPD) is a rare intraepithel ial neoplasm arising in apocrine gland-bearing skin. EMPD may be regarded as a skin marker of associated malignancy because it tends to combine a variety of underlying malignancies in up to 50% of cases. Herein a case of gastric cancer diagnosed in a patient with extramammary Paget's disease of the scrotum is reported. The patient was a 65-year-old man whose chief complaint was exanthema of the right scrotum of 3 years duration. Biopsy samples taken from patient showed large, round cells with clear cytoplasm in the epidermis. The final diagnosis was EMPD of the scrotum. The extensive workups, including tumor marker, imaging studies and endoscopy to exclude associated malignancy were performed. Examination of the endoscopic gastric biopsy specimen revealed an adenocarcinoma of the stomach. On the basis of this result, a radical subtotal gastrectomy was successfully performed. This case suggests that, in cases of EMPD, the clinicians should consider the possibility of underlying malignancies and thoroughly examine not only the urogenital tract and lower gastrointestinal tract, but also the visceral organs, such as the stomach, even if there are no clinical symptoms of malignancy.