EXPRESSION OF BCL-2 IN THE DEVELOPING HUMAN FETAL AND INFANT BREAST

The expression of BCL-2 protein was analysed in 10 fetal and 45 infant breast specimens by immunocytochemical staining of methacarn-fixed, p araffin-embedded tissue. In the developing fetal breast bud, BCL-2 was expressed in the basal cell layer and in the surrounding mesenchyme. Basal cells of epithelial buds destined to become hair follicles also expressed BCL-2 while the basal cell layer of the epidermis was negati ve. In infant breasts studied (aged 0-2 years), there was heterogeneou s staining of the luminal epithelial cells of the ducts and lobules an d no staining of myoepithelial cells or fibroblasts. The intensity of staining had a strong positive correlation with the age of the infant. Although the function of the bcl-2 gene in epithelial cells is unknow n, these findings suggest that bcl-2 has a role in the morphogenesis o f the human breast, and may help to sustain active epithelial-mesenchy mal interaction by inducing longevity of certain cells.