Abstract 4409
Background
Worldwide, Breast cancer (BC) is the leading cause of cancer-related mortality in women. In Argentina, breast cancer is the second leading cause of death in women, with an incidence of 18.47%. Given the importance of breast cancer for public health, and the diversity of patients’ response to current therapies, the identification of new therapeutic targets is crucial. Rac1 is a Rho GTPase widely involved in motility, mitogenesis, transformation, and metastasis. P-Rex1 is a Rac1 activator essential for the migration of breast cancer cells. It has been reported that P-Rex1 is overexpressed in breast cancer of the luminal type and that its silencing inhibits the migration of cancer cells. In order to validate P-Rex1 as a therapeutic target and/or prognostic biomarker, we aimed to analyze its presence in samples of Argentinean patients from the Marie Curie Hospital of Buenos Aires City, and determine its relationship with clinical and histopathological parameters.
Methods
The levels of P-Rex1 were determined both in biopsy material and in tumor tissue (and its corresponding healthy adjacent tissue) from primary surgery of patients not undergoing neoadjuvant therapy. The levels of messenger RNA (mRNA) were analyzed by quantitative PCR and protein by western blot (WB) and immunohistochemistry.
Results
When the mRNA levels of the biopsies classified according to the molecular subtype were compared, elevated P-Rex1 levels were observed not only in those samples classified as ER+/PR+ breast cancer but also in 50% of the samples of triple negative breast cancer (TNBC). These data were validated by an in-silico analysis made from public access databases (Metabric and the GEO repository of NCBI). P-Rex overexpression in TNBC patients has not been previously reported. The aberrant expression of P-Rex1 was detected in all stages of the disease, and a negative correlation between the expression of P-REX1 and the proliferation marker Ki-67 was determined. P-Rex1 levels were significantly higher in tumors compared to normal breast samples, in agreement with previous reports.
Conclusions
These results confirm the potential of P-Rex1 as a therapeutic target not only for the treatment of luminal tumors but also for a certain population of TNBC patients.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Eva Wertheimer.
Funding
Instituto Nacional del Cáncer-Ministerio de Salud-Argentina (INC, Asistencia Financiera IV, 2018).
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4852 - Impact of routine screening and preemptive treatment on hepatitis B virus reactivation (HBVr) in patients receiving chemotherapy
Presenter: Celine Marty
Session: Poster Display session 1
Resources:
Abstract
5225 - The uptake, patient satisfaction and efficacy of scalp cooling among patients receiving chemotherapy in an Irish oncology day ward.
Presenter: William Maher
Session: Poster Display session 1
Resources:
Abstract
1901 - Placebo adverse events (AEs) in targeted and immune cancer therapy in the adjuvant and advanced setting: A systematic review and meta-analysis
Presenter: Diego Enrico
Session: Poster Display session 1
Resources:
Abstract
3258 - Reduced antibody levels and high seronegativity rates against vaccine preventable diseases pose a risk factor for infections in patients with solid and hematologic cancers
Presenter: Angela Guzek
Session: Poster Display session 1
Resources:
Abstract
3211 - Prognostic Factors Influencing Outcome After Therapy With Brentuximab Vedotin in Patients with Relapsed or Refractory Hodgkin's Lymphoma
Presenter: Veselina Goranova - Marinova
Session: Poster Display session 1
Resources:
Abstract
4949 - Phase I Study of CC-90010 in Patients With Advanced Solid Tumors and Relapsed/Refractory Non-Hodgkin Lymphoma (R/R NHL)
Presenter: Victor Moreno
Session: Poster Display session 1
Resources:
Abstract
2271 - Pretreatment coagulation factors related to prognosis in patients with natural killer/T cell lymphoma
Presenter: Yue Chai
Session: Poster Display session 1
Resources:
Abstract
4335 - Diffuse large B cell lymphoma in the elderly. A retrospective analysis of standard versus alternative treatments
Presenter: Irene Sillero
Session: Poster Display session 1
Resources:
Abstract
5117 - MIPI as a superior prognostic tool in Mantle Cell Lymphoma compared to monocyte-lymphocyte, neutrophil-lymphocyte and platelet-lymphocyte ratios
Presenter: Filipa Macedo
Session: Poster Display session 1
Resources:
Abstract
5135 - Dose adjustment of chemotherapy in aggressive lymphoma using automated and standardized analysis and evaluation of DNA double strand breaks
Presenter: Julia Schröder
Session: Poster Display session 1
Resources:
Abstract