43P - XIST and TSIX; novel cancer-immune biomarkers showing differential expression in Tumor, PBMCs, Serum, nipple discharge and lymph nodes of PD-L1 ove...

Date 08 December 2017
Event ESMO Immuno-Oncology Congress 2017
Session Lunch & Poster Display session
Topics Bioethics, Legal, and Economic Issues
Presenter Esraa Atef
Citation Annals of Oncology (2017) 28 (suppl_11): xi6-xi29. 10.1093/annonc/mdx711
Authors E. Atef1, R. Abdel Tawab2, H.M. El Tayebi1
  • 1Genetic Pharmacology Research Group, Department Of Pharmacology And Toxicology, German University in Cairo, 11835 - Cairo/EG
  • 2Emeritus General Surgery, Ain Shams University, 11835 - Cairo/EG

Abstract

Background

Despite the success of immunotherapies, patients still respond differently. Thus, there is an urge to explore novel predictive biomarkers to understand the complex interactions within cancer immunity. Long non-coding RNAs (lncRNAs) were found to act as biomarkers in breast cancer (BC). X inactive –specific transcript (XIST) has been proved to be an indicator of poor outcome in BC. TSIX is the antisense of XIST and both LncRNAs were shown to have crucial role in breast carcinogenesis. However, no evidences were reported about their role in immune evasion. Our previous data proved that XIST and TSIX were able to paradoxically manipulate PD-L1 expression in BC cell lines. This study aims at investigating the potential role of XIST and TSIX as cancer-immune biomarkers in relation to the PD-L1 expression in different body compartments of BC patients.

Methods

BC biopsies, Lymph nodes (LN), whole blood, serum and nipple discharge(ND) were collected from 35 BC patients (15.7% triple negative BC (TNBC), 36.8% luminal B, 21.05% luminal A, 10.5%Her2+ and 15.78% luminal B Her2+). PBMCs were isolated using Ficoll-Hypaque method. Total RNA extraction was performed using BIOZOL reagent, then the expression profiling of PD-L1, XIST & TSIX was quantified by Taqman Real Time qPCR and normalized to Beta-2-microglobulin.

Results

The relative expression of XIST and TSIX was markedly increased in tumor biopsies (p = 0.0493 and p = 0.0173), PBMCs (p = 0.0414 and p = 0.029), Serum (p = 0.0144 and p = 0.0336) and ND (p = 0.0197 and p 

Conclusions

This study introduces XIST and TSIX as novel immune biomarkers that are highly correlated with the expression profile of PD-L1 in different body compartments of BC.

Clinical trial identification

Legal entity responsible for the study

German University in Cairo, Egypt

Funding

None

Disclosure

All authors have declared no conflicts of interest.