Open Access Highly Accessed Research article

Overexpression of prostate tumor overexpressed 1 correlates with tumor progression and predicts poor prognosis in breast cancer

Fangyong Lei1, Longjuan Zhang2, Xinghua Li1, Xi Lin3, Shu Wu1, Fengyan Li4* and Junling Liu5*

Author Affiliations

1 State Key Laboratory of Oncology in South China, Guangzhou 510060, China

2 Laboratory of Surgery, First Affiliated Hospital, Sun Yat-sen University, No.58 Zhongshan 2nd Rd, Guangzhou 510080, China

3 Ultrasonic department, Sun Yat-sen University Cancer Center, Guangzhou 510060, China

4 State Key Laboratory of Oncology in South China and Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou 510060, China

5 State Key Laboratory of Oncology in South China and Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou 510060, China

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BMC Cancer 2014, 14:457  doi:10.1186/1471-2407-14-457

Published: 19 June 2014

Abstract

Background

Prostate tumor overexpressed 1 (PTOV1) was demonstrated to play an important role in cancer progression and was correlated with unfavorable clinical outcome. However, the clinical role of PTOV1 in cancer remains largely unknown. This study aimed to investigate the expression and clinicopathological significance of PTOV1 in breast cancer.

Methods

The mRNA and protein expression levels of PTOV1 were analyzed in 12 breast cancer cell lines and eight paired breast cancer tumors by semi-quantitative real time-PCR and western blotting, respectively. Immunohistochemistry was performed to assess PTOV1 protein expression in 169 paraffin-embedded, archived breast cancer samples. Survival analysis and Cox regression analysis were performed to investigate the clinicopathological significance of PTOV1 expression.

Results

Our data revealed that PTOV1 was frequently overexpressed in breast cancer cell lines compared to normal human breast epithelial cells and in primary breast cancer samples compared to adjacent noncancerous breast tissues, at both the mRNA and protein levels. Moreover, high expression of PTOV1 in breast cancer is strongly associated with clinicopathological characteristics and estrogen receptor expression status (P = 0.003). Breast cancer patients with higher PTOV1 expression had substantially shorter survival times than patients with lower PTOV1 expression (P < 0.001). Univariate and multivariate analysis revealed that PTOV1 might be an independent prognostic factor for breast cancer patients (P = 0.005).

Conclusions

Our study showed that PTOV1 is upregulated in breast cancer cell lines and clinical samples, and its expression was positively associated with progression and aggressiveness of breast cancer, suggesting that PTOV1 could serve as an independent prognostic marker.

Keywords:
PTOV1; Breast cancer; Prognosis; Biomarker