Proliferation markers (ki-67 and PCNA), p53 and bcl-2 in congenital tumors

Congenital tumors are very uncommon, occurring in 1-4/100,000 live births. They are predominantly benign. However, it would be very important to determine proliferative activity, and the expression of p53 and bcl-2 to predict the biological behavior of these tumors. Immunohistochemistry was performed on paraffin embedded archival material. Microwave pretreatment was performed to improve immunostaining. The intensity of staining was graded semiquantitatively. There were 14 benign and 10 malignant congenital tumors of different histologic types. Weak expression of proliferation markers and p53 was observed in benign congenital tumors. Malignant tumors, especially rhabdomyosarcomas, showed slight to strong expression of the investigated markers. There was a statistically significant difference in the expression of bcl-2 in malignant tumors (p<0.05) while the expression of PCNA, Ki-67 and p53 between the groups of benign and malignant tumors was not significant. Factor analysis showed a correlation between malignancy and the immunohistochemical expression of bcl-2 (p=0.000062) and PCNA (p=0.03552). There was no correlation between clinical parameters (sex, age, and tumor size) and other investigated markers. Our results suggest that PCNA, Ki-67, p53 and bcl-2 are present, particularly in malignant congenital tumors. The exact role of these markers in the pathogenesis of these tumors should be further analyzed in larger studies of particular tumor types.