The prognostic effect of PTEN expression status in colorectal cancer development and evaluation of factors affecting it: miR-21 and promoter methylation.

Yazdani, Yaghoub; Farazmandfar, Touraj; Azadeh, Hossein; Zekavatian, Zeinab

Background: PTEN is a tumor suppressor gene which is involved in cellular proliferation, differentiation, and apoptosis. Loss or down-regulation of PTEN plays an important role in human cancers development. In this study, we investigated the effect of miR-21 and promoter methylation on the PTEN expression status in CRC tissues and analyzed association of the PTEN expression status with clinicopathological features in patients with CRC. Results: The PTEN expression was positively detected in 67.2 % CRC tissues and all adjacent non-cancerous samples. PTEN mRNA level was negatively correlated with miR-21 level (r = −0.595, P < 0.001). PTEN expression was also correlated directly with the PTEN mRNA level (r = 0.583, P < 0.001) and conversely with miR-21 level (r = −0.632, P < 0.001). PTEN Promoter methylation was significantly associated with PTEN expression status (p = 0.013). PTEN expression was negatively associated with tumor size (p = 0.007) and advanced tumor stage (P = 0.011). Multivariate analysis indicated that tumor stage, tumor differentiation and PTEN expression status were independent prognostic factors for overall carcinoma in CRC patients (P < 0.05). The Kaplan-Meier curve indicated a negative correlation between PTEN expression levels and survival of CRC patients (P = 0.013). Conclusions: This study suggests a high frequency of miR-21 overexpression and aberrant promoter methylation in down-regulation of PTEN expression in colorectal carcinoma. Loss of PTEN may be a prognostic factor for patients with CRC.

PTEN protein; TUMOR suppressor genes; CELL proliferation; CELL differentiation; APOPTOSIS; METHYLATION; MULTIVARIATE analysis

Journal of Biomedical Science, 2016, Vol 23, p1

1021-7770

Academic Journal

10.1186/s12929-016-0228-5