p16INK4a, PTEN, E-cadherin, Bcl-2 and Ki-67 Expression in Prostate Cancer: Its Relationship with the Metastatic Potential and Known Prognostic Factors

ABSTRACT

BACKGROUND: At present, adequate prognostic markers for prostate cancer progression are still lacking, in spite of intensive investigation. Accordingly, our study examined the relationship between expression of candidate biomarkers and metastasis in prostate cancer patients. Correlation of molecular markers with prostate-specific antigen (PSA) level, Gleason sum score and tumor stage were also evaluated. METHODS: A total of 105 prostate tumor specimens and specimens from 19 cases of nodular hyperplasia were obtained through Yeungnam University Hospital from 2007 to 2008. Immunohistochemical analyses for p16INK4a, phosphatase and tensin homolog (PTEN), E-cadherin, Ki-67 and Bcl-2 were performed. RESULTS: Overexpression of Bcl-2 was significantly related to bone (p = 0.006) and nodal metastases (p = 0.017). Other biomarkers were not related to metastatic potential. There were statistically significant relationships between increased PSA level and loss of expression of PTEN (p = 0.019) and E-cadherin (p = 0.001). High Ki-67 index was significantly correlated with nodal metastasis (p = 0.029) as well as with loss of p16INK4a expression (p = 0.002) and high Gleason score (p = 0.011). CONCLUSIONS: High Gleason score, Bcl-2 overexpression and increased Ki-67 labeling have significant predictive value in assessing the potential for prostate cancer metastasis. In addition, a high Ki-67 index is related to high Gleason score and loss of p16INK4a expression.