Abstract P5-09-06: Decrease of tumor F3 expression after neoadjuvant chemotherapy associates to lower survival in breast cancer
Authors: Ginés Luengo-Gil, Enrique González-Billalabeitia, Rocío González-Conejero, Asunción Chaves-Benito, Elena García-Martínez, Gloria Soler-Sánchez, Elisa García-Garre, Lorena Velázquez, Vicente Vicente, Francisco Ayala de la Peña
Journal: Cancer Research (2015)

Abstract Background: Pathologic complete response (pCR) is the main prognostic factor after neoadjuvant chemotherapy (nCT) for breast cancer (BC). However, in cases without pCR, additional prognostic biomarkers are needed for subsequent prognostic and therapeutic stratification of patients. Tissue factor (F3) is the protease initiator of blood coagulation cascade and is expressed in solid tumors including BC. F3 oncogenic functions derive both from coagulation activation and from its cytoplasmic domain, although they are not well known yet. Prognostic impact of F3 circulating levels and tumor expression seems to be variable, and no studies evaluating F3 expression changes in the residual tumor after nCT are available. Our aim was to evaluate chemotherapy-mediated changes in F3 mRNA levels and their prognostic value in BC treated with nCT. Methods: RNA was isolated from FFPE samples of pre- and post-CT tumors. Post-CT F3 levels were analyzed only in patients without primary tumor pCR. Quantification of F3 was performed by RT-qPCR. F3 expression was categorized as no expression or above/below median expression. Change in expression levels (ΔF3), defined as pre-nCT minus post-nCT, was categorized by value of change (positive vs. negative). Association of F3 levels with clinical and pathological characteristics and analysis of paired samples was evaluated with non-parametric tests. Kaplan-Meier curves, log-rank test and Cox proportional hazard regression multivariate models were used for survival analysis. To externally validate our results, we also studied the correlation between F3 and the rest of the set of genes in the TCGA database. The best 150 directly and 150 inversely correlated genes (r &amp;gt;0.3 and &amp;lt;-0.3 respectively) were selected and functional prediction was performed using Genemania software for both groups. Results: We included 108 consecutive women with invasive BC, mostly with stages IIB or IIIA-C; Her2+: 25.0%, triple negative: 22.2%. After nCT including anthracyclines and taxanes, pCR rate was 19.4%. nCT significantly increased F3 expression (p&amp;lt;0.000001). Pre-CT F3 levels were not associated with prognostic or predictive variables in our series. Loss or low post-CT F3 levels were associated with poor prognosis only in the univariate analysis. However, a nCT-induced decrease in F3 expression had a negative impact on overall survival in both univariate and multivariate analysis including cN (p=0.001 and 0.013 respectively). Both in our series and in external databases, F3 mRNA levels have an inverse correlation with proliferative genes, and nCT enhances these correlations (pre-CT: MYBL2: r=-0.358, p=0.001; MKI67: r=-0.267, p=0.019; post-CT: MYBL2: r=-0.495, p&amp;lt;0.001; MKI67: r=-0.498, p&amp;lt;0.001). A functional strong inverse correlation between F3 and mitotic functions was also confirmed in TCGA database. Conclusion: Our data demonstrate that nCT consistently increases tumor F3 expression. However, those cases with decreased expression of F3 after chemotherapy show poor overall survival rates. Functional analysis in our series and in public databases demonstrate that decreased F3 mRNA expression correlates with an increased mitotic activity, suggesting that low F3 mRNA levels could be a marker of active and resistant to treatment tumors. Citation Format: Ginés Luengo-Gil, Enrique González-Billalabeitia, Rocío González-Conejero, Asunción Chaves-Benito, Elena García-Martínez, Gloria Soler-Sánchez, Elisa García-Garre, Lorena Velázquez, Vicente Vicente, Francisco Ayala de la Peña. Decrease of tumor F3 expression after neoadjuvant chemotherapy associates to lower survival in breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-09-06.