Simultaneous copy number gains of NUPR1 and ERBB2 predicting poor prognosis in early-stage breast cancer
1 Integrated Research Center for Genome Polymorphism, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, Republic of Korea
2 Department of Microbiology, The Catholic University of Korea, Seoul, South Korea
3 Department of Hospital Pathology, Humanities and Social Sciences, The Catholic University of Korea, Seoul, South Korea
4 Department of Medical Humanities and Social Sciences, The Catholic University of Korea, School of Medicine, 505 Banpo-dong, Seocho-gu, Seoul, 137-701, South Korea
BMC Cancer 2012, 12:382 doi:10.1186/1471-2407-12-382Published: 31 August 2012
The full extent of chromosomal alterations and their biological implications in early breast carcinogenesis has not been well examined. In this study, we aimed to identify chromosomal alterations associated with poor prognosis in early-stage breast cancers (EBC).
A total of 145 EBCs (stage I and II) were examined in this study. We analyzed copy number alterations in a discovery set of 48 EBCs using oligoarray-comparative genomic hybridization. In addition, the recurrently altered regions (RARs) associated with poor prognosis were validated using an independent set of 97 EBCs.
A total of 23 RARs were defined in the discovery set. Six were commonly detected in both stage I and II groups (> 50%), suggesting their connection with early breast tumorigenesis. There were gains on 1q21.2-q21.3, 8q24.13, 8q24.13-21, 8q24.3, and 8q24.3 and a loss on 8p23.1-p22. Among the 23 RARs, copy number gains on 16p11.2 (NUPR1) and 17q12 (ERBB2) showed a significant association with poor survival (P = 0.0186 and P = 0.0186, respectively). The patients simultaneously positive for both gains had a significantly worse prognosis (P = 0.0001). In the independent replication, the patients who were double-positive for NUPR1-ERBB2 gains also had a significantly poorer prognosis on multivariate analysis (HR = 7.31, 95% CI 2.65-20.15, P = 0.0001).
The simultaneous gain of NUPR1 and ERBB2 can be a significant predictor of poor prognosis in EBC. Our study will help to elucidate the molecular mechanisms underlying early-stage breast cancer tumorigenesis. This study also highlights the potential for using combinations of copy number alterations as prognosis predictors for EBC.