Immunohistochemical expression of BCL-2 in hydatidiform moles: a tissue microarray study

Area of Science:

• Reproductive Biology
• Oncology
• Pathology

Background:

• Gestational trophoblastic diseases (GTD) encompass hydatidiform moles (HM), which can progress to gestational trophoblastic neoplasia (GTN).
• HMs are classified as partial (PHM) or complete (CHM), with diagnostic challenges in some cases.
• Investigating biomarkers like BCL-2 is crucial for understanding HM progression and diagnosis.

Purpose of the Study:

• To investigate the expression of BCL-2 protein in partial hydatidiform moles (PHM), complete hydatidiform moles (CHM), and normal trophoblastic tissues.
• To utilize immunohistochemistry (IHC) and Tissue MicroArray (TMA) techniques for precise BCL-2 expression analysis.
• To correlate BCL-2 expression levels with histopathological subtypes of HM.

Main Methods:

• Tissue MicroArrays (TMAs) were constructed from 237 HMs (95 PHM, 142 CHM) and 202 normal trophoblastic tissues (products of conception and placentas).
• Immunohistochemical staining for BCL-2 was performed on TMA sections.
• Staining intensity and percentage of positive cells in trophoblasts and stromal cells were assessed semi-quantitatively.

Main Results:

• BCL-2 demonstrated cytoplasmic expression in over 95% of trophoblasts across all groups (PHM, CHM, controls).
• A significant reduction in BCL-2 staining intensity was observed from controls (73.7%) and PHM (76.3%) to CHM (26.9%).
• Statistically significant differences in BCL-2 intensity and overall scores were found between PHM and CHM (p<0.0005), but not in percentage scores.

Conclusions:

• Reduced BCL-2 expression in CHM compared to PHM and normal trophoblasts suggests increased apoptosis and potentially uncontrolled proliferation.
• The TMA technique, using duplicate cores, proved effective in overcoming tissue heterogeneity in complex lesions.
• BCL-2 expression serves as a potential indicator for differentiating HM subtypes and assessing disease progression.