Increase of N1,N12-diacetylspermine in tissues from colorectal cancer and its liver metastasis

摘要

Purpose: N1,N12-Diacetylspermine (DiAcSpm) is a tumor marker featured by increase in the urine of patients with cancers, including early colorectal cancer, but where and how DiAcSpm is made remains unclear. We aimed to clarify whether colorectal cancer tissues produce increased amounts of DiAcSpm, and if they do, to examine whether tissue DiAcSpm level may serve as a criterion of tissue malignancy. Methods: Tissue samples were obtained from 140 patients (13 low-grade intraepithelial neoplasia, 98 high-grade intraepithelial neoplasia and 29 colorectal cancer) treated for colorectal cancer and intraepithelial neoplasia at Tokyo Metropolitan Komagome Hospital between November 2007 and April 2011. The DiAcSpm level in cancer and adjacent normal tissue extracts was compared, and its relationship with clinical stages of the diseases was analyzed. Results: DiAcSpm levels were higher in colorectal cancer tissue (p 0.01, n = 12) and its liver metastasis (p 0.05, n = 5) than in adjacent normal tissues. The tumorormal ratio of tissue DiAcSpm content was examined for endoscopically obtained tumor and adjacent normal tissues from patients with intraepithelial neoplasia. The ratio was greater than 1.5 in 38 % (5/13) and 78 % (84/108) of low-grade intraepithelial neoplasia and high-grade intraepithelial neoplasia, respectively. Conclusions: Tissue DiAcSpm levels increase in the tissue of colorectal cancer and also in precancerous lesion, such as high-grade intraepithelial neoplasia. The increase is considered a sign that a tissue is acquiring malignant characteristics. It is likely that the DiAcSpm produced by cancer cells is responsible for the frequent increase in urinary DiAcSpm in early cancer patients.