Immunohistochemical profiling of Wilms tumor: a tissue microarray study

Area of Science:

• Oncology
• Pathology
• Immunohistochemistry

Background:

• Wilms tumor (WT) typically presents with a tri-phasic morphology involving blastemal, stromal, and epithelial cells.
• Distinguishing WT from other biphasic renal tumors in small biopsy samples can be diagnostically challenging.
• Accurate diagnosis is crucial for appropriate patient management and treatment.

Purpose of the Study:

• To investigate the utility of various immunohistochemical markers in differentiating Wilms tumor from mimickers in small biopsy specimens.
• To identify a panel of antibodies that can reliably aid in the diagnosis of Wilms tumor.
• To enhance diagnostic accuracy in challenging cases encountered in preoperative needle biopsies.

Main Methods:

• A tissue microarray was constructed from 45 cases of Wilms tumors.
• Immunohistochemical reactions were evaluated using a panel of 37 antibodies across blastemal, stromal, and epithelial components.
• Cores from paraffin blocks were analyzed to assess marker expression patterns.

Main Results:

• Blastemal elements showed significant expression of CD56, CD57, CK22, and CK8.
• Epithelial cells were predominantly positive for CK22, CK18, CK8, CD57, CD56, EMA, and CK19.
• Stromal cells demonstrated expression of SMA, actin, desmin, CD34, CD57, and CD56.
• Several markers were negative across all components, aiding in differential diagnosis.

Conclusions:

• CD56, CD57, CK22, CK18, CK8, EMA, SMA, and actin are valuable immunohistochemical markers for diagnosing Wilms tumor.
• These markers are particularly useful in small biopsy samples where morphology may be limited.
• The study provides a reliable panel to improve diagnostic accuracy for Wilms tumor.