Abstract 36P
Background
Platforms that enable multiplexed analysis of biomarkers from limited amounts of poor-quality material provide value to studies of archival tissue material. The NanoString nCounter® technology allows nonamplified measurements of up to 800 targets within one sample of archived formalin fixed paraffin embedded (FFPE) material. We aimed to compare gene expression in young vs old breast cancer (BC) patients, using archived FFPE material to gain insight into BC biology of the young.
Methods
The NanoString BC360 panel was explored by NanoString nCounter® to investigate gene expression in an in-house BC FFPE archive cohort (diagnosed 1996-2003; age <50 years at diagnosis; n= 129). Data were analysed in nSolver and ROSALIND. Protein-protein interaction (PPI) networks were explored. The Cancer Genome Atlas global gene expression BC data (n=520) was analyzed for validation.
Results
We identified 58 differentially expressed genes (DEGs) in BC samples from young (aged <40) and older patients. In PPI networks, representing the DEGs, we identified highly interconnected regions (sub-clusters), pointing to DEGs indicating increased immune infiltration and inflammatory mechanisms, as well as oncogenic signaling favoring tumor promotion, in BC of the young. Validation in TCGA BC data demonstrated gene expression patterns reflecting overall increased T-cell activation and higher levels of T regulatory immune cells and PD-1 in BC of the young (P<0.04).
Conclusions
The current study indicates increased immune cell activation supporting an immune evasive environment in young BC. Also, higher oncogenic signaling in this patient subset supports increased tumor-promoting processes.
Legal entity responsible for the study
The authors.
Funding
Helse Vest and University of Bergen.
Disclosure
All authors have declared no conflicts of interest.