Molecular signature of response to preoperative radiotherapy in locally advanced breast cancer

Background: Radiation therapy is an indispensable part of various treatment modalities for breast cancer. Specifically, for non-inflammatory locally advanced breast cancer (LABC) patients, preoperative radiotherapy (pRT) is currently indicated as a second line therapy in the event of lack of response to neoadjuvant chemotherapy. Still approximately one third of patients fails to respond favourably to pRT. The aim of this study was to explore molecular mechanisms underlying differential response to radiotherapy (RT) to identify predictive biomarkers and potential targets for increasing radiosensitivity.Methods: The study was based on a cohort of 134 LABC patients, treated at the Institute of Oncology and Radiology of Serbia (IORS) with pRT, without previous or concomitant systemic therapy. Baseline transcriptional profiles were established using Agilent 60 K microarray platform in a subset of 23 formalin-fixed paraffin-embedded (FFPE) LABC tumour samples of which 11 radiotherapy naïve and 3 post-radiotherapy samples passed quality control and were used for downstream analysis. Biological networks and signalling pathways underlying differential response to RT were identified using Ingenuity Pathways Analysis software. Predictive value of candidate genes in the preoperative setting was further validated by qRT-PCR in an independent subset of 60 LABC samples of which 42 had sufficient quality for data analysis, and in postoperative setting using microarray data from 344 node-negative breast cancer patients (Erasmus cohort, GSE2034 and GSE5327) treated either with surgery only (20%) or surgery with RT (80%).Results: We identified 192 significantly differentially expressed genes (FDR < 0.10) between pRT-responsive and non-responsive tumours, related to regulation of cellular development, growth and proliferation, cell cycle control of chromosomal replication, glucose metabolism and NAD biosynthesis II route. APOA1, MAP3K4, and MMP14 genes were differentially expressed (FDR < 0.20) between pRT responders and non-responders in preoperative setting, while MAP3K4 was further validated as RT-specific predictive biomarker of distant metastasis free survival (HR = 2.54, [95%CI:1.42–4.55], p = 0.002) in the postoperative setting.Conclusions: This study pinpoints MAP3K4 as a putative biomarker of response to RT in both preoperative and postoperative settings and a potential target for radiosensitising combination therapy, warranting further pre-clinical studies and prospective clinical validation

The influence of PTEN protein expression on disease outcome in premenopausal hormone receptor positive early breast cancer patients treated with adjuvant ovarian ablation: a long-term follow-up

PURPOSE: All breast cancer (BC) patients with detectable hormone receptors (HR) expression should be offered endocrine therapy (ET). In premenopausal patients, tamoxifen and/or ovarian suppression (OvS)/ablation (OA) may improve disease outcome. Alteration of phosphatase and tensin homolog (PTEN) signaling pathways could be one of the possible mechanisms of resistance to antiestrogen therapy. The purpose of this study was to investigate the association of PTEN protein expression with prognostic factors such as tumor histology and grade, estrogen receptor (ER) and progesterone receptor (PgR) status, human epidermal growth factor receptor 2 (HER2) and disease outcome in premenopausal patients with HR-positive early BCs treated with adjuvant OA. METHODS: We analyzed a group of premenopausal early stages I/II HR-positive BC patients who had undergone radical mastectomy followed only with adjuvant OA by irradiation. ER and PgR contents were determined by classical biochemical dextran-coated charcoal (DCC) method, HER2 status by chromogen in situ hybridization (CISH) analysis and PTEN status by immunohistochemistry (IHC). RESULTS: Sixty-six premenopausal patients included into this analysis were followed for a median of 17 years (range 17-29). Compared to PTEN-positive BCs, PTEN-negative BCs were significantly more frequently associated with lobular tumor histology (p<0.05), higher ER content (p<0.05), and had significantly decreased disease-free survival (DFS) and overall survival (OS) (p<0.01 for both) compared to patients with PTEN-positive BCs. CONCLUSIONS: It seems that PTEN status determined by protein expression may discriminate between subgroups with poor and good prognosis in premenopausal HR-positive BC patients receiving adjuvant OA

Association of uPA and PAI-1 tumor levels and 4G/5G variants of PAI-1 gene with disease outcome in luminal HER2-negative node-negative breast cancer patients treated with adjuvant endocrine therapy

Abstract Background The aim of this study was to evaluate the prognostic potential of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) tumor tissue levels and examine the association between these biomarkers and classical prognostic factors in early node-negative luminal breast cancer patients. The clinical value of 4G/5G variants of PAI-1 gene was evaluated. Patients and methods This study involved 81 node-negative, estrogen receptor-positive and/or progesterone receptor-positive and human epidermal growth factor receptor 2-negative operable breast cancer patients who underwent radical surgical resection and received adjuvant endocrine therapy. Determination of uPA and PAI-1 concentrations in the breast cancer tissue extracts was performed using FEMTELLE® uPA/PAI-1 ELISA. An insertion (5G)/deletion (4G) polymorphism at position − 675 of the PAI-1 gene was detected by PCR-RFLP analysis. Results Our research showed that patients with uPA tumor tissue levels higher than 3 ng/mg of protein had significantly reduced disease-free survival (DFS) and overall survival (OS) when compared to patients with uPA tumor tissue levels lower or equal to 3 ng/mg of protein. Patients with PAI-1 tumor tissue levels higher than 14 ng/mg of protein had significantly decreased OS in comparison with patients with PAI-1 tumor tissue levels lower or equal to 14 ng/mg of protein. ROC analysis confirmed the uPA and PAI-1 discriminative potential for the presence/absence of relevant events in these patients and resulted in higher cut-off values (5.65 ng/mg of protein for uPA and 27.10 ng/mg of protein for PAI-1) than standard reference cut-off values for both biomarkers. The prognostic importance of uPA and PAI-1 ROC cut-off values was confirmed by the impact of uPA higher than 5.65 ng/mg of protein and PAI-1 higher than 27.10 ng/mg of protein on poorer DFS, OS and event-free survival (EFS). We observed that patients with dominant allele in PAI-1 genotype (heterozygote and dominant homozygote, − 675 4G/5G and − 675 5G/5G) had significantly increased DFS, OS and EFS when compared with patients with recessive homozygote genotype (− 675 4G/4G). Conclusion Our study indicates that uPA and PAI-1 tumor tissue levels and 4G/5G variants of PAI-1 gene might be of prognostic significance in early node-negative luminal HER2-negative breast cancer patients treated with adjuvant endocrine therapy