Prognostic and clinicopathological value of poly (adenosine diphosphate-ribose) polymerase expression in breast cancer: A meta-analysis

Abstract

Background: Previous studies have shown that the poly (adenosine diphosphate-ribose) polymerase (PARP) level is a promising indicator of breast cancer. However, its prognostic value remains controversial. The present meta-analysis evaluated the prognostic value of PARP expression in breast cancer.

Materials and methods: Eligible studies were retrieved from the PubMed, Web of Science, Embase, and Cochrane Library databases through July 20, 2016. Studies investigating PARP expression as well as reporting survival data in breast cancer were included. Two independent reviewers carried out all literature searches. The pooled relative risk (RR) and hazard ratio (HR) with 95% confidence interval (95% CI) were applied to assess the association between PARP expression and the clinicopathological features and survival outcome in breast cancer.

Results: A total of 3506 patients from eight eligible studies were included. We found that higher PARP expression indicated a worse clinical outcome in early stage breast cancer, with a HR of 3.08 (95% CI, 1.14-8.29, P = 0.03) for disease-free survival and a HR of 1.82 (95% CI, 1.20-2.76; P = 0.005) for overall survival. Moreover, increased PARP expression was significantly associated with higher nuclear grade (RR, 1.51; 95% CI, 1.12-2.04; P = 0.008) in breast cancer. A similar correlation was detected in triple-negative breast cancer (TNBC; RR, 1.81; 95% CI, 1.04-3.17; P = 0.04).

Conclusions: Our findings indicated that elevated PARP expression correlated with worse prognosis in early stage breast cancer. Furthermore, high PARP expression was associated with higher nuclear grade and TNBC.

Fig 1. Flow diagram for identification of retrieved publications.

From: Moher D, Liberati A, Tetzlaff j, Altman DG, The PRISMA Group (2009). Preferred Reporting items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLOS Med 6(7):e1000097. doi: 10.1371/journal.pmed1000097 For more information, visit www.prisma-statement.org.

Fig 2. Forest plot for studies investigating the hazard ratio (HR) for PARP expression and disease-free survival (DFS) in breast cancer.

Fig 3. Forest plot for publications assessing the hazard ratio (HR) for PARP expression and breast cancer overall survival (OS).

Fig 4. Forest plots for enrolled studies showing positive associations between the PARP expression level and (A) nuclear grade (3 vs. 1 and 2) and (B) triple-negative breast cancer (TNBC) (positive vs. negative).

Fig 5. Forest plots for enrolled studies showing that there were no associations between PARP expression and (A) age (≥50 vs. <50 years), (B) tumor size (large vs. small), (C) lymph node metastasis (positive vs. negative), and (D) BRCA1 status (positive vs. negative).

Fig 6. Forest plots for enrolled studies showing that there were no associations between PARP expression and (A) ER expression (positive vs. negative), (B) PR expression (positive vs. negative), (C) HER2 expression (positive vs. negative), and (D) Ki67 level (high vs. low).

Fig 7. Forest plot for enrolled publications showing that there was no correlation between PARP level and pCR in breast cancer.