Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster Display session 2

5716 - Mutation analysis of B2M gene in colorectal cancer patients with microsatellite instability


29 Sep 2019


Poster Display session 2


Tumour Site

Colon and Rectal Cancer


Ivana Kašubová


Annals of Oncology (2019) 30 (suppl_5): v198-v252. 10.1093/annonc/mdz246


I. Kašubová1, Z. Sňahničanová1, M. Kalman2, L. Plank3, Z. Lasabová4

Author affiliations

  • 1 Division Of Oncology, Biomedical center Martin, Jessenius Faculty of Medicine in Martin, 03601 - Martin/SK
  • 2 Department Of Pathological Anatomy, Jessenius Faculty of Medicine in Martin, 03601 - Martin/SK
  • 3 Department Of Pathological Anatomy, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, 3659 - Martin/SK
  • 4 Department Of Molecular Biology And Genomics, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, 03601 - Martin/SK


Login to access the resources on OncologyPRO.

If you do not have an ESMO account, please create one for free.

Abstract 5716


Mutations in genes involved into antigen presentation such as B2M are enriched among colorectal cancer (CRC) patients with high microsatellite instability (MSI-H) and can become negative predictors for checkpoint inhibitor therapy. The aim of this study was the determination of prevalence of B2M somatic mutations in MSI-H CRC patients and relationship between B2M mutations and lymphocytes infiltration and other clinicopathological features. We focused also for methylation status of B2M promoter as another possible mechanism of gene expression downregulation.


From our study group enrolling 420 CRC patients, 37 MSI-H and 5 MSI-L patients were selected for screening of B2M mutational status. The characterization of patients was based on standard histopathological diagnosis, TNM classification, tumor-infiltrating lymphocytes and peritumoral lymphoid reactions were determined. MSI analysis was performed using fragment analysis. BRAF, KRAS and B2M mutational status were identified by Sanger sequencing. For methylation analysis of B2M promoter region was used nested methylation specific PCR.


B2M mutations were detected in 5 MSI-H patients (13.5%). In four cases, heterozygous mutation c.45_48delTTCT located in exon 1 was present and 2 patients exhibited heterozygous mutation c.276delC in exon 2. From group of 5 MSI-H patients, one case was compound heterozygote for both these mutations. Methylation of B2M promoter was observed only in 1 MSI-H case from our study group.


The presence of B2M mutations should be correlated with the response to the checkpoint inhibitor therapy in order to improve patient’s stratification and also development of new immunotherapeutic approaches. Our pilot study recommends detection of CpG methylation in B2M gene for the future studies in the area of colorectal cancer.

Clinical trial identification

Editorial acknowledgement

Biomedical Center Martin (ITMS 26220220187), APVV-16-0066 and VEGA 1/0380/18.

Legal entity responsible for the study

The authors.


All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.