Abstract 5813
Background
Biliary Tract Cancers (BTC) are a devastating and molecularly heterogeneous group of diseases, with significant differences between intrahepatic (ICC) and extrahepatic (ECC) cholangiocarcinoma and Gall bladder (GB) cancer. O6-methylguanine-DNA methyltransferase (MGMT) is a key DNA repair gene, responsible of alkyl groups’ elimination from the O6-position of guanine. Reductions in MGMT expression and MGMT promoter methylation result in diminished DNA-repair of O6-alkylguanine adducts and enhanced sensitivity to alkylating agents, such as temozolomide (TMZ). This alterations have been described in BTC in small reports with variable frequencies. Here we present data on MGMT methylation tested in BTC pts admitted at our center.
Methods
MGMT promoter methylation was studied via methyl specific PCR (EZ DNA Methylation-Gold™ KIT), while protein expression was assessed with immunohistochemistry (IHC). Formalin-fixed paraffin-embedded (FFPE) tissue samples were also examined using Next Generation Sequencing (50 genes “Hotspot Cancer Panel, Ion Torrent®”).
Results
Archived FFPE tissue sections from 100 pts admitted at Fondazione IRCCS Istituto Nazionale dei Tumori of Milan from October 2017 to February 2019 were analyzed. Amongst the 89 samples with adequate tissue, 73% were ICC, 16% were ECC and 8 % were GC. 34 pts (38%) had MGMT promoter methylation, while low/negative MGMT protein expression was found in 45 pts (50%). MGMT methylation was identified in 38% of ICC, 26% of ECC and 62% of GC. As expected, we identified IDH1/2 mutations in 15%, all affected by ICC. Of note, amongst MGMT methylated pts, there were 4 pts (11%) with concomitant IDH1/2 mutations, which are reported to be associated with CpG Island Methylator Phenotype.
Conclusions
MGMT is a prognostic and predictive marker in glioblastomas and there is an increasing evidence in its role in gastrointestinal cancer, with phase II studies showing a response rate of 10% in chemorefractory MGMT- methylated colorectal cancer treated with TMZ. In our single center experience, MGMT methylation was found in 38% of patients with BTC. This data warrant further confirmation, but there is a growing interest in novel targeted therapies exploiting the role of MGMT methylation as a predictive and prognostic biomarker in BTC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
F. Morano: Honoraria (institution): Servier. F. Pietrantonio: Honoraria (institution), Advisory / Consultancy: Roche; Honoraria (institution), Advisory / Consultancy: Amgen; Honoraria (institution), Advisory / Consultancy: EMD Serono; Honoraria (institution), Advisory / Consultancy: Sanofi; Honoraria (institution), Advisory / Consultancy: Bayer; Honoraria (institution), Advisory / Consultancy: Servier; Research grant / Funding (self): BMS. M. Di Bartolomeo: Honoraria (institution), Advisory / Consultancy: Eli Lilly; Honoraria (institution), Advisory / Consultancy: Servier; Travel / Accommodation / Expenses: Roche. F.G.M. De Braud: Speaker Bureau / Expert testimony: Bayer; Advisory / Consultancy, Speaker Bureau / Expert testimony: BMS; Advisory / Consultancy: Celgene; Advisory / Consultancy, Speaker Bureau / Expert testimony: Novartis; Advisory / Consultancy: Servier; Advisory / Consultancy: Pharm Research Associated; Advisory / Consultancy: Daiichi Sankyo; Advisory / Consultancy, Speaker Bureau / Expert testimony: Ignyta; Advisory / Consultancy, Speaker Bureau / Expert testimony: Amgen; Advisory / Consultancy, Speaker Bureau / Expert testimony: Pfizer; Speaker Bureau / Expert testimony: ACCMED; Advisory / Consultancy: Incyte; Advisory / Consultancy: Teofarma; Advisory / Consultancy: Pierre Fabre; Advisory / Consultancy, Speaker Bureau / Expert testimony: Roche; Advisory / Consultancy: EMD Serono; Speaker Bureau / Expert testimony: Eli Lilly; Speaker Bureau / Expert testimony: AstraZeneca; Speaker Bureau / Expert testimony: Fondazione Menarini; Speaker Bureau / Expert testimony: MSD. All other authors have declared no conflicts of interest.
Resources from the same session
3668 - Patient Demographics and Management Landscape of Metastatic Colorectal Cancer in the Third Line Setting: real-world data in an Australian Population
Presenter: Sandy Tun Min
Session: Poster Display session 2
Resources:
Abstract
3907 - Exploration of efficacious alternative regorafenib regimens to manage hand-foot-skin-reaction (HFSR)
Presenter: Axel Grothey
Session: Poster Display session 2
Resources:
Abstract
3958 - Quality of Life (QoL) in Metastatic Colorectal Cancer (mCRC) in the Real World: Final Results of a European Survey
Presenter: Zorana Maravic
Session: Poster Display session 2
Resources:
Abstract
3563 - BISQUIT: A Randomized Phase II Study of the Administration of Prebiotics and Probiotics During Definitive Treatment With Chemotherapy-radiotherapy for Patients With Squamous Cell Carcinoma of the Anal Canal
Presenter: Rachel Riechelmann
Session: Poster Display session 2
Resources:
Abstract
1184 - iSCORE: Immunotherapy Sequencing in COlon and REctal Cancer
Presenter: Fiona Turkes
Session: Poster Display session 2
Resources:
Abstract
3346 - Phase II study of preoperative (PREOP) chemoradiotherapy (CTRT) plus avelumab (AVE) in patients (PTS) with locally advanced rectal cancer (LARC): The AVANA Study
Presenter: Lisa Salvatore
Session: Poster Display session 2
Resources:
Abstract
3895 - A phase II study of capecitabine plus concomitant radiation therapy followed by durvalumab (MEDI4736) as preoperative treatment in rectal cancer: PANDORA study.
Presenter: Maria Aurelia Barbera
Session: Poster Display session 2
Resources:
Abstract
2012 - Open Label Phase III Study of Arfolitixorin vs. Leucovorin in mFOLFOX-6 for First Line Treatment of Metastatic Colorectal Cancer: AGENT
Presenter: Josep Tabernero
Session: Poster Display session 2
Resources:
Abstract
2198 - SOLSTICE, a phase 3, randomized, open label study of trifluridine/tipiracil+bevacizumab (bev) versus capecitabine+bev for the 1L treatment of patients with unresectable metastatic colorectal cancer (mCRC) who are not candidates for intensive therapy
Presenter: Thierry Andre
Session: Poster Display session 2
Resources:
Abstract
2921 - A Phase Ib/ II Trial to Assess the Safety and Efficacy of CXD101 in Combination with the PD-1 Inhibitor Nivolumab in Patients with Metastatic, Previously-Treated, Microsatellite-Stable (MSS) Colorectal Carcinoma (short title CAROSELL)
Presenter: Mark Saunders
Session: Poster Display session 2
Resources:
Abstract