Abstract 2316
Background
Neoadjuvant chemotherapy (NACT) is the treatment option for locally advanced breast cancer (BC). However, more than half of the patients have no response. Thus, there is an urgent need to find biomarkers of NACT response and personalized therapies for non-responders. Recently, we described a biomarker of NACT response, assessed both in biopsy and blood - HLA-DR expressing cytotoxic T cells (CTLs) with a sensitivity and specificity of 94.12% and 100%, respectively. HLA-DR is associated with CTLs’ cytotoxicity, and it was only observed in NACT-responders, suggesting that functional CTLs are required in the tumor for NACT success. Now, we are validating these results in an independent cohort. Simultaneously, we are establishing 3D spheroid co-culture platforms to tackle new therapeutic options for NACT non-responders.
Methods
MCF7 BC cell line was used to spontaneously form a spheroid in agarose coated plates. Peripheral blood mononuclear cells (PBMCs) from NACT-responders or non-responders were added after spheroid formation and they were able to infiltrate the structure. Doxorubicin (doxo), anti-PD-1 and anti-PD-L1 were added in different combinations.
Results
The validation of HLA-DR level in CTLs to predict NACT response has been in agreement with the first cohort. Regarding the BC spheroids, doxo alone or in combination with NACT non-responders PBMCs (low HLA-DR in CTLs) did not affect them. However, when PBMCs from NACT responders (high HLA-DR in CTLs) were added in combination with doxo, the viability and proliferation of MCF7 cells reduced significantly. Notably, when PBMCs from NACT non-responders were stimulated ex vivo, to increase CTLs’ HLA-DR level and IFN-γ production (p = 0.002), MCF7 cells viability decreased (p = 0.0007). Considering that in biopsies of non-responders, the low HLA-DR level in CTLs was negatively correlated with the expression of tumor PD-L1, we are also exploring this platform to inhibit the PD-1/PD-L1 axis in order to stimulate the PBMCs and decrease BC cells viability.
Conclusions
Besides determining if BC patients will respond to NACT, by analysing HLA-DR levels in CTLs, we will now be able to define the best therapy to NACT non-responders, hopefully improving the BC treatment.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Fundação para a Ciência e Tecnologia (FCT) - PD/BD/114023/2015 and PTDC/BBB-BMD/4497/2014. Liga Portuguesa Contra o Cancro - LPCC-NRS/Terry Fox 2019/2020.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2344 - Lung Cancer in Europe: strengthening policy responses to address unmet needs
Presenter: Mary Bussell
Session: Poster Display session 3
Resources:
Abstract
1359 - Curative treatment timelines for breast, colorectal, lung and prostate cancer: Implications for medical leave coverage
Presenter: Selina Wong
Session: Poster Display session 3
Resources:
Abstract
4433 - Acute Diagnostic Oncology Clinic: A Unique Primary Care-Oncology Service
Presenter: Abhijit Gill
Session: Poster Display session 3
Resources:
Abstract
3506 - THE NEW MUTATIONAL MODEL IN ONCOLOGY. What changes in welfare, clinical practice, research, and regulatory procedures
Presenter: Nicola Normanno
Session: Poster Display session 3
Resources:
Abstract
3350 - Selection of a set of quality indicators (QI) for oncological clinical pathway
Presenter: Aude Fourcade
Session: Poster Display session 3
Resources:
Abstract
4400 - Sustainable drug prices at market launch: policy proposals and their empirical evidence
Presenter: Nora Fanzen
Session: Poster Display session 3
Resources:
Abstract
4118 - Impact of financial considerations on French physicians’ prescription choices for advanced non-small cell lung cancer (NSCLC)
Presenter: Nathalie Olympios
Session: Poster Display session 3
Resources:
Abstract
1340 - The direct medical cost of breast cancer in a Belgian hospital
Presenter: Hannan Lemhouer
Session: Poster Display session 3
Resources:
Abstract
1863 - Does the healthcare system approaches cancer patients for using private services during diagnostic process?
Presenter: Karolina Osowiecka
Session: Poster Display session 3
Resources:
Abstract
2637 - Measuring financial toxicity of cancer in the Italian health care system: initial results of the patient reported outcome for Fighting Financial Toxicity of cancer project (proFFiT).
Presenter: Silvia Riva
Session: Poster Display session 3
Resources:
Abstract