Evaluating The Association Between FATS MRNA Level And Prognosis In Breast Cancer

ObjectiveFATS is a newly identified tumor suppressor gene involved in radiation-induced tumorigenesis. The purpose of this study was to evaluate the clinical significance of FATS expression in breast cancer.MethodsTissue samples from patients (n=156) with histologically confirmed breast cancer and 42 controls in tumor bank were studied (median follow-up,6.0 years). FATS gene expression was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Follow-up through May 1,2010, was obtained from retrospective chart review and patient questionnaires.Results1. The expression of FATS mRNA was silent or downregulated in 95.2% of tested breast cancer samples in comparison with paired normal controls (n=42, P< 0.0001). mRNA expression differences of FATS between malignant and non-malignant breast tissues. In the 42 cases with paired primary breast cancers for real-time PCR, FATS mRNA levels were downregulated more than 3 fold (from 3.25 to 9698.19 fold) in cancers2. The cut-off value (5.3E-07) for distingaishing positive or negative status of FATS expression in breast tissues was determined by receiver operating characteristic (ROC) curve. No significant differences of FATS were found between the mRNA level of FATS and age, tumor size, clinical stage, Menopausal status, lymph node status, Estrogen receptor, Progestogen receptor and Her2 status (P>0.05). The mRNA of FATS was significantly lower in the high nuclear grade group than in the low nuclear grade group (P=0.01).3. When we examined the clinical outcomes according to FATS expression levels in two subgroups (negative and positive), patients with FATS-negative breast tumors had poor disease-free survival (P=0.036) in Kaplan-Meier log rank analysis;Stronger associations with outcome were found when the analysis was restricted to the patients receiving adjuvant radiotherapy (P=0.006). Multivariate analysis disclosed that FATS expression was an independent prognostic factor in breast cancer(odds ratio, 0.549;95%confidence interval,0.308 to 0.977;P=0.041) and possessed the prognostic value in predicting response to adjuvant radiotherapy (odds ratio,0.377; 95% confidence interval,0.176 to 0.909;P=0.012). ConclusionThe expression of FATS mRNA was silent or downregulated in breast cancer samples in comparison with paired normal controls. FATS expression is clinically significant and appears to be an independent marker for assessing sensitivity to adjuvant radiotherapy in advanced breast cancer.