Apoptosis and bcl-2 oncogene expression in Wilms' tumor

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Wilms' tumor (WT) typically has a favorable prognosis, but advanced stages and anaplastic features are associated with poorer outcomes.
• Apoptosis, a key process in regulating cell numbers, occurs with variable frequency in malignant tumors and may influence growth rates.
• The bcl-2 proto-oncogene is known to inhibit apoptosis, potentially contributing to tumor development by increasing cell survival.

Purpose of the Study:

• To investigate the role of apoptosis and bcl-2 proto-oncogene expression in the development and progression of Wilms' tumor.
• To correlate apoptotic index (AI) and bcl-2 expression with tumor stage, histological type, and patient survival in Wilms' tumor.

Main Methods:

• Analysis of 26 resected Wilms' tumor specimens, categorized by stage (I-V) and histology (favorable/unfavorable).
• Detection of apoptosis using the in-situ end-labeling technique to calculate the apoptotic index (AI).
• Assessment of bcl-2 expression via immunohistochemistry.

Main Results:

• The apoptotic index (AI) was significantly lower in higher tumor stages (e.g., Stage I vs. IV) and in tumors with unfavorable histology compared to favorable histology.
• A lower AI was observed in patients who died compared to those who survived.
• No correlation was found between AI and bcl-2 expression across all studied specimens.

Conclusions:

• Disruptions in apoptosis regulation mechanisms may be linked to the progression of Wilms' tumor to advanced stages and poor prognosis.
• Bcl-2 does not appear to function as a direct regulator of apoptosis in Wilms' tumor.
• Other oncogenes and tumor-suppressor genes likely play a more significant role in inhibiting apoptosis in Wilms' tumor.