Abstract 4794: Tn (GalNAcα1-O-Ser/Thr) in serum mucin: a potential cancer biomarker

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Mucin-related carbohydrate epitope, Tn (GalNAcα1-O-Ser/Thr), is expressed in epithelial tumors including breast, prostate, and ovarian cancer. Since the expression of Tn was shown to define the stage, rate, and phenotype of tumor progression as well as the diagnosis, Tn may offer as useful information for prognostic purposes. However, Tn-based tumor diagnosis requires the immunohistochemistry (IHC) staining of tumor tissue. A simple and noninvasive assay for tumor diagnosis is desirable. This study is taken an effort to examine whether Tn in serum mucin can be used as biomarker for cancer diagnosis. To reach this goal, we must have an anti-Tn antibody with high affinity and high specificity. This study presents a novel carrier protein containing a binding domain to the receptor of antigen presenting cells and cysteine-rich repeat peptide to serve as docking sites for conjugating Tn, as a result, to collaboratively activate T-cells and B-cells. This novel carrier protein after conjugation with Tn can effectively elicit high titer of IgG1 antibodies rather than IgM against Tn with high specificity in all immunized mice and rabbits. Applying this anti-Tn antibody, we observed that Tn expression by IHC assay is highly significantly correlated with the malignancy of tumors. We then applied anti-Tn antibody to detect the Tn in serum mucin of 12 lung cancer patients. The results showed that the levels of Tn were high in serum mucin of 11 out of 12 lung cancer patients, while the levels of serum mucin Tn are relatively low in normal people, suggesting that the levels of Tn in serum mucin may be a potential cancer biomarker. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4794.