Impact of preoperative chemotherapy on the expression of apoptosis factors in colorectal cancer liver metastases

OBJECTIVE: To study the effects of cytotoxic and targeted anti-VEGF drugs on some mechanisms of apoptosis. MATERIAL AND METHODS: The effects of cytotoxic and targeted anti-VEGF drugs on the expression of the apoptosis activators Bax and PML and the apoptosis inhibitor Bcl-2 were studied in the colorectal cancer (CRC) liver metastases; a comparison group comprised patients receiving no chemotherapy. RESULTS: Immunohistochemical examination revealed lower Bax and PML expressions and higher Bcl-2 expression in the majority of untreated patients, suggesting the suppressed mechanisms triggering tumor cell apoptosis. Cytotoxic therapy resulted in a statistically significant rise in the expression of the apoptosis activator Bax (p = 0.01), a reduction in the level of the apoptosis inhibitor Bcl-2 (p = 0.04) and a slight increase in PML that controlled the induction of apoptosis. Adding an anti-VEGF agent to cytotoxic therapy exerted no statistically significant impact on Bax and Bcl-2, but caused more frequent positive PML expression than in the control and cytotoxic chemotherapy groups. CONCLUSION: Our study showed that cytotoxic and targeted anti-VEGF agents activate the apoptosis of tumor cells in the CRC liver metastases.