Gene expression of PMP22 is an independent prognostic factor for disease-free and overall survival in breast cancer patients

• Published in: BMC cancer 2010-12, Vol.10 (1), p.682-682, Article 682
• Main Authors: Tong, Dan, Heinze, Georg, Pils, Dietmar, Wolf, Andrea, Singer, Christian F, Concin, Nicole, Hofstetter, Gerda, Schiebel, Ingrid, Rudas, Margaretha, Zeillinger, Robert
• Format: Article
• Language: English
• Subjects: Austria; Biomarkers, Tumor - analysis; Biomarkers, Tumor - genetics; Breast cancer; Breast Neoplasms - genetics; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Cancer therapies; Carcinoma, Ductal, Breast - genetics; Carcinoma, Ductal, Breast - mortality; Carcinoma, Ductal, Breast - pathology; Carcinoma, Lobular - genetics; Carcinoma, Lobular - mortality; Carcinoma, Lobular - pathology; Disease-Free Survival; Female; Genetic aspects; Humans; Kaplan-Meier Estimate; Mammography; Medical statistics; Membrane Glycoproteins - genetics; Middle Aged; Mortality; Myelin proteins; Myelin Proteins - genetics; Neoplasm Staging; Pathology; Physiological aspects; Prognosis; Proportional Hazards Models; Receptors, Estrogen - analysis; Receptors, Estrogen - genetics; Reproducibility of Results; Retrospective Studies; Reverse Transcriptase Polymerase Chain Reaction; Risk Assessment; Risk Factors; Survival Rate; Time Factors; Tumors
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/1471-2407-10-682

Gene expression of peripheral myelin protein 22 (PMP22) and the epithelial membrane proteins (EMPs) was found to be differentially expressed in invasive and non-invasive breast cell lines in a previous study. We want to evaluate the prognostic impact of the expression of these genes on breast cancer. In a retrospective multicenter study, gene expression of PMP22 and the EMPs was measured in 249 primary breast tumors by real-time PCR. Results were statistically analyzed together with clinical data. In univariable Cox regression analyses PMP22 and the EMPs were not associated with disease-free survival or tumor-related mortality. However, multivariable Cox regression revealed that patients with higher than median PMP22 gene expression have a 3.47 times higher risk to die of cancer compared to patients with equal values on clinical covariables but lower PMP22 expression. They also have a 1.77 times higher risk to relapse than those with lower PMP22 expression. The proportion of explained variation in overall survival due to PMP22 gene expression was 6.5% and thus PMP22 contributes equally to prognosis of overall survival as nodal status and estrogen receptor status. Cross validation demonstrates that 5-years survival rates can be refined by incorporating PMP22 into the prediction model. PMP22 gene expression is a novel independent prognostic factor for disease-free survival and overall survival for breast cancer patients. Including it into a model with established prognostic factors will increase the accuracy of prognosis.