Abstract
Simple SummaryIn breast cancer, the promising efficacy of farnesyltransferase inhibitors (FTIs) in preclinical studies is in contrast to only limited effects in clinical trials. Therefore, this study focussed on the clinical relevance of polymorphisms in FNTB, the gene encoding the catalytically active β-subunit of farnesyltransferase, in early breast cancer. This is the first study on breast cancer suggesting that FNTB promoter polymorphisms are independent prognostic biomarkers, particularly in patients with early triple negative breast cancer (TNBC), and possibly modulate FNTB transcriptional activity. Taken together, we describe for the first time, a link between FNTB promoter polymorphism and the prognosis of breast cancer patients. We propose that FNTB genotyping, which is easily possible from a single blood drawing, may allow independent prognostic stratification, particularly in TNBC, in order to identify patients with a high risk of recurrence and poor prognosis. Ultimately, our results encourage further prospective evaluations of the role of FNTB promoter polymorphisms in predicting response to FTIs, particularly in TNBC patients.In breast cancer, the promising efficacy of farnesyltransferase inhibitors (FTIs) in preclinical studies is in contrast to only limited effects in clinical Phase II–III trials. The objective of this study was to explore the clinical relevance of farnesyltransferase β-subunit (FNTB) single nucleotide promoter polymorphisms (FNTB-173 6G > 5G (rs3215788), -609 G > C (rs11623866) and -179 T > A (rs192403314)) in early breast cancer. FNTB genotyping was performed by pyrosequencing in 797 patients from a prospective multicentre observational PiA trial (NCT 01592825). In the total cohort, the FNTB-173 6G > 5G polymorphism was an independent predictor of RFI (HR = 0.568; 95% CI = 0.339–0.949, p = 0.031), OS (HR = 0.629; 95% CI = 0.403–0.980, p = 0.040) and BCSS (HR = 0.433; 95% CI = 0.213–0.882; p = 0.021), whereas the FNTB-609 G > C polymorphism was an independent predictor of RFI (HR = 0.453; 95% CI = 0.226–0.910, p = 0.026) and BCSS (HR = 0.227; 95% CI = 0.075–0.687, p = 0.009). Subtype analysis revealed the independent prognostic relevance of FNTB promoter polymorphisms, particularly in TNBC but not in luminal or HER2-positive intrinsic subtypes. Finally, we used electrophoretic mobility shift assays (EMSAs) to confirm in vitro that the polymorphism FNTB-173 6G > 5G resulted in the differential binding of nuclear proteins from five different breast cancer cell lines. This is the first study on breast cancer suggesting that FNTB promoter polymorphisms (i) are independent prognostic biomarkers, particularly in patients with early TNBC, and (ii) could modulate FNTB’s transcriptional activity.
Highlights
Breast cancer is one of the major causes of cancer-related deaths worldwide
Association of farnesyltransferase β-subunit (FNTB) Promoter Polymorphisms with Clinical and Pathological Parameters of FNTB genotyping was performed by pyrosequencing in 797 patients from a representative cohort of non-metastasized early breast cancer patients (51.7% pT1, 42.9% pT2, 4.6% pT3, 0.8% pT4; 76% luminal, 13.9% HER2-positive, 10% triple negative breast cancer, TNBC), recruited in the prospective multicentre observational PiA trial (NCT 01592825)
We observed a correlation between FNTB-173 6G > 5G and the histopathological grading at borderline significance (p = 0.048)
Summary
Breast cancer is one of the major causes of cancer-related deaths worldwide. Despite recent advances in early detection and systemic treatment, about 20–30% of patients with early breast cancer experience distant metastatic relapse, which constitutes the predominant cause of breast cancer-specific death [1,2,3,4]. RAS oncogenes encode membrane-associated small guanosine triphosphate (GTP)ases that transduce signals from activated membrane receptors to downstream kinases [5]. For exerting their signalling activity, RAS proteins need post-translational modification, such as farnesylation, which confers them with lipophilic properties and allows their attachment to the cell membrane [6].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
