Abstract 3542
Background
Programmed cell death protein 6 (PDCD6) mediates apoptosis via p53 dependent and independent pathways and is implicated in many cancer hallmarks. A multi-omics analysis of colorectal cancer (CRC) cell lines identified PDCD6 as a candidate prognostic and predictive biomarker. PDCD6 is dysregulated in different cancers, but the role of PDCD6 in CRC is still poorly understood.
Methods
The clinicopathological data on 483 CRC patients treated at Mater Dei Hospital Malta between January 2008 and December 2011 were collated and tissue microarrays constructed in triplicate to represent central and peripheral tumour areas. PDCD6 protein expression was quantified by multiplex immunofluorescence (mIF; QuPath) along with fifteen other protein targets representing important cancer signalling and immune pathways. Expression of 770 genes was assessed using the NanoString nCounter® PanCancer Pathways Panel in a subset of 34 patients with low/high PDCD6 expression. Associations with clinicopathological parameters including disease-free survival and overall survival (OS) were calculated.
Results
Intra-tumoural PDCD6 protein expression was heterogeneous, having a higher expression at the tumour edge (p = 0.001). Invasive edge PDCD6 protein expression was significantly associated with TNM stage and tumour grade (p = 0.04 and <0.001, respectively), with lower PDCD6 expression in higher stage and poorly differentiated CRCs. PDCD6 expression was also associated with 5-year OS (p = 0.003), and higher PDCD6 expression revealed a trend towards longer OS. PDCD6 and Ki67 expression were negatively correlated (rs = - 0.192, p = 0.002). Low and high PDCD6 expressers showed differential gene expression in several other cancer pathways.
Conclusions
PDCD6 shows both inter- and intra-tumoural heterogeneity in CRC, with expression patterns consistent with a tumour suppressive function. Contrarily, wider literature suggests that PDCD6 might also have an intrinsic oncogenic role under certain circumstances, and further exploration of PDCD6 pleiotropism in CRC is warranted.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Romina Briffa.
Funding
REACH HIGH Scholars Programme Part-financed by the European Union, Operational Programme II; Cohesion Policy 2014-2020 "Investing in human capital to create more opportunities and promote the wellbeing of society.".
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
3988 - Basal NK activity and early Treg function inhibition predicts Nivolumab responsiveness in metastatic renal cancer patients (REVOLUTION) trial.
Presenter: Sara Santagata
Session: Poster Display session 3
Resources:
Abstract
2142 - Low NK Cell Abundance Correlates with High Expression of PD-1 in CD8+ T Cells
Presenter: Moon Hee Lee
Session: Poster Display session 3
Resources:
Abstract
5501 - Tobacco smoking is associated with the immune suppressive microenvironment in head and neck squamous cell carcinoma (HNSCC)
Presenter: Christine Chung
Session: Poster Display session 3
Resources:
Abstract
5726 - Evaluation of Antibody-Dependent Cell Cytotoxicity (ADCC) in lung cancer cell lines treated with combined anti-EGFR and anti-PD-L1 therapy.
Presenter: Francesca Sparano
Session: Poster Display session 3
Resources:
Abstract
2534 - Radiomic Signatures for Identification of Tumors Sensitive to Nivolumab or Docetaxel in Squamous Non-Small Cell Lung Cancer (sqNSCLC)
Presenter: Laurent Dercle
Session: Poster Display session 3
Resources:
Abstract
3366 - Analysis of gut microbiota in advanced non-small cell lung cancer (NSCLC) patients treated with immune-checkpoints blockers
Presenter: FEIYU ZHANG
Session: Poster Display session 3
Resources:
Abstract
2089 - Pathogenesis of Myocarditis Following Treatment with Immune Checkpoint Inhibitors in a Cynomolgus Monkey Model
Presenter: Changhua Ji
Session: Poster Display session 3
Resources:
Abstract
4463 - Effects of dietary restriction in cancer patients receiving irinotecan
Presenter: Ruben Van Eerden
Session: Poster Display session 3
Resources:
Abstract
4841 - Investigating the Link between Burn Injury and Tumorigenesis
Presenter: Lucy Barrett
Session: Poster Display session 3
Resources:
Abstract
4619 - Prognostic value of the neutrophil-lymphocyte, platelet-lymphocyte and monocyte-lymphocyte ratio in male breast cancer patients
Presenter: Joanna Huszno
Session: Poster Display session 3
Resources:
Abstract