RM2 antigen (β 1,4-GalNAc-Disialyl-Lc 4): A novel carbohydrate marker for prostate cancer

Seiichi Saito, Shin Egawa, Akihiro Ito, Yoichi Arai

Research output: Contribution to journalArticlepeer-review


Prostate-specific antigen (PSA) is widely used for detection and diagnosis of early prostate cancer. However, PSA has a problem with specificity and does not reflect the grade of malignancy. In addition, Thompson et al. recently pointed out that PSA also lacks sensitivity. Therefore, a new serum marker, which can detect early prostate cancer more efficiently, is urgently required. In efforts to explore new serum markers for prostate cancer, serum protein fingerprinting by SELDI-TOF-MS, carbohydrate changes of free PSA, and EPCA have been reported as promising markers. We found that a novel carbohydrate antigen, β 1,4-GalNAc-disialyl-Lc 4, defined by monoclonal antibody RM2, is a new marker for prostate cancer, reflecting the malignant potential. RM2 antigen was expressed in adenocarcinoma whereas little or none was detected in benign glands. RM2 immunoreactivity was also detected in stroma of radical prostatectomy specimens, suggesting that RM2 antigen is shed into the surrounding stroma from prostate cancer and then released into the bloodstream. Difference of RM2 immunoreactivity in serum between prostate cancer and benign prostate was observed on a glycoprotein with an approximate mass, 40-45 kDa (GPX). RM2 immunoreactivity on GPX had a high sensitivity and a relatively high specificity for detecting early prostate cancer. Although larger trials are required, RM2 antigen may be a useful serum marker for detecting early prostate cancer.

Original languageEnglish
Pages (from-to)418-426
Number of pages9
Issue number4
Publication statusPublished - 2006 Jul


  • Carbohydrate
  • Marker
  • Prostate cancer
  • RM2 antigen

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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