Blood group precursor T-antigen expression in human urinary bladder carcinoma

Area of Science:

• Oncology
• Immunohistochemistry
• Cancer Biomarkers

Background:

• ABH blood group antigen (BGAg) deletion is linked to poor bladder cancer prognosis.
• The T antigen (TAg), a precursor to BGAg, is typically masked in normal cells but exposed in malignant cells.
• Neuraminidase (NMD) can unmask cryptic TAg in normal tissues.

Purpose of the Study:

• To evaluate the prognostic significance of T antigen (TAg) expression in bladder cancer.
• To determine if TAg expression can predict tumor invasiveness, especially in ABH blood group antigen-negative cases.

Main Methods:

• Paraffin-embedded bladder cancer tissues and controls were stained using a T-specific lectin (peanut agglutinin [PNA]) via immunoperoxidase.
• T antigen (TAg) expression was assessed in normal tissues, low-grade/low-stage cancers, and high-grade cancers.
• Neuraminidase (NMD) treatment was used to unmask cryptic TAg.

Main Results:

• Normal tissues expressed TAg only after NMD treatment (Cryptic TAg+).
• High-grade bladder cancers showed either TAg expression (TAg+) or loss of T structure (Cryptic TAg-).
• TAg+ or Cryptic TAg- status in low-grade/low-stage cancers correlated with a higher rate of subsequent invasion (39%) compared to Cryptic TAg+ (10%).
• In ABH BGAg-negative low-grade/low-stage cancers, TAg+ or Cryptic TAg- status predicted invasiveness (64%) more than Cryptic TAg+ (17%).

Conclusions:

• T antigen (TAg) expression, particularly its altered presentation (TAg+ or Cryptic TAg-), is a prognostically significant marker in bladder cancer.
• TAg serves as a valuable immunohistochemical marker for predicting invasiveness, especially in tumors lacking ABH blood group antigens.