LYNKED IN 2020 Conference at Dana Farber Cancer Institute: Keynote Speaker Matthias Kloor

MSI cancer evolution and immunoediting

2020 Lynch Syndrome Virtual Patient Conference

The 5th Annual LYNKED IN conference for individuals and families of those with Lynch syndrome was held on Saturday, September 12, 2020.

  • Over 750 attendees registered for the event from 39 states and 14 countries.
  • The conference brought together over 230 attendees in a live virtual series of talks and Q&A sessions.
  • Advocacy groups joined LYNKED IN this year in post-conference break-out rooms.

Matthias Kloor gave this years’ Keynote Lecture at the virtual LYNKED IN Conference and talked about the latest advances in vaccine development for Lynch syndrome-associated tumors. For watching this and other video presentations from LYNKED IN 2020 please click here.

Immune surveillance and immunoediting in microsatellite-unstable cancers: our new publication in Nature Communications

MSI cancer evolution and immunoediting

© DKFZ

The shared frameshift mutation landscape of microsatellite-unstable cancers suggests immunoediting during tumor evolution

Cancer evolution recapitulates basic principles of biology in a nutshell, as surviving cell clones over time acquire mutations that allows them to thrive in an often hostile and changing environment. Adaptation processes leave their traces in the genome of manifest cancers, so studying cancer genomes can open a window into the past. In this sense, analyzing mutation signals in tumor genomes to unravel early steps of tumor formation shares similarities to cosmology research measuring cosmic microwave background noise to shed light on the origin and history of the universe.

The present study was a collaboration between the Heidelberg University Hospital, the DKFZ Heidelberg, Heidelberg University, the Heidelberg Institute for Theoretical Studies (HITS) and international collaboration partners. We developed ReFrame, a new algorithm to quantitatively detect microsatellite indel mutations with high sensitivity. Using ReFrame, we identified mutations shared by most MSI colorectal and endometrial cancers.

We further discovered a negative correlation between the prevalence of a defined indel mutation in MMR-deficient colorectal or endometrial cancers and the predicted immunogenicity of the resulting frameshift peptide. Our study strongly supports the concept of continuous immunoediting in human cancers and provides new evidence for the hypothesis that immunogenic cancers and pre-cancer cell clones can be attacked and potentially eradicated by the host’s immune system.

This strongly encourages the concept of neoantigen-based cancer-preventive vaccines that may in the future help to reduce tumor risk in Lynch syndrome and potentially beyond. We have recently demonstrated the safety and immunological efficacy of a prototype frameshift peptide vaccine in a phase I/IIa clinical trial.

New publication in the “Mathematics in Oncology” collaboration

cos efficacy of BRAF testing

© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of Union for International Cancer Control

Age-dependent performance of BRAF mutation testing in Lynch syndrome diagnostics (doi: 10.1002/ijc.33273)

In frame of the “Mathematics in Oncology” collaborative initiative between ATB and the Engeneering Mathematics and Computing Lab (EMCL), Heidelberg University (https://emcl.iwr.uni-heidelberg.de/), we aim to gain novel insights into cancer evolution through mathematical modeling of the underlying complex biological processes.
We focus on microsatellite-unstable (MSI) cancers, which show a high number of mutations due to a deficiency of the DNA mismatch repair system responsible for repairing mistakes occuring during DNA replication.

MSI cancers develop in elderly patients sporadically and in younger patients in the context of Lynch syndrome, the most common inherited colorectal cancer syndrome. Lynch syndrome is associated with an increased life time risk of developing cancer in the large bowel (colorectal cancer), the endometrium and other organs.

Lynch syndrome is estimated to affect 1 out of 280 individuals, yet often remains undiagnosed. Thus, a diagnostic procedure with high sensitivity and specificity is of central clinical significance. As BRAF V600E mutations have been reported to be associated with sporadic MSI cancers, current international diagnostic guidelines recommend using BRAF mutations in order to distinguish between sporadic and likely hereditary MSI colorectal cancer. Due to a significant difference in age at diagnosis between sporadic and hereditary MSI CRC patients, we hypothesized that the performance of BRAF testing for identifying sporadic MSI CRC could be age-dependent.
In our recent study, we systematically analyzed data from published studies, public databases and population-base patient cohorts. In addition, we performed sensitivity analysis as well as cost calculations of BRAF testing.
We identified that though being highly effective in older patients, BRAF testing led to a high risk of missing Lynch syndrome patients and increased costs at age <50 years, thereby showing its poor performance in this age group. We therefore suggest to directly refer MSI CRC patients <50 years to genetic counseling without BRAF testing.

The study was developed through the active Mathematics in Oncology collaboration (Link: https://emcl.iwr.uni-heidelberg.de/research/projects/mathematical-oncology) with the Engeneering Mathematics and Computing Lab (EMCL, Head: Vincent Heuveline), Heidelberg University Hospital, together with the Department of General Pathology, Institute of Pathology, University Hospital Leipzig and various institutions of other German universities. Hendrik Bläker from the University Hospital Leipzig, Michael Hoffmeister from the Division of Clinical Epidemiology and Aging Research, DKFZ (German Cancer Research Center), Aysel Ahadova and Matthias Kloor, both from ATB (Head: Magnus von Knebel Doeberitz), designed the study, collected and analyzed data from different sources. From EMCL, Saskia Haupt and Vincent Heuveline were strongly involved in the analysis and interpretation of the data. The study titled “Age-dependent performance of BRAF mutation testing in Lynch syndrome diagnostics” (doi: 10.1002/ijc.33273) was recently published in the International Journal of Cancer.

Molecular diversity of Lynch syndrome colorectal cancer reflected in clinical disease manifestation: an international study published in Gastroenterology

cos efficacy of BRAF testing

© Matthias Kloor

Associations of Pathogenic Variants in MLH1, MSH2, and MSH6 With Risk of Colorectal Adenomas and Tumors and With Somatic Mutations in Patients With Lynch Syndrome. (doi: 10.1053/j.gastro.2019.12.032)

Lynch syndrome is the most common inherited colorectal cancer syndrome. The affected individuals carry a germline variant in one of the mismatch repair genes (MLH1, MSH2, MSH6 and PMS2), enhancing their lifetime risk of developing a broad spectrum of tumors, most commonly colorectal and endometrial cancer. In order to prevent colorectal cancer, colonoscopy with polypectomy is recommended for Lynch syndrome carriers. However, the reasons for colorectal cancer development under regular colonoscopy surveillance in some Lynch syndrome carriers are unknown.

In our previous study, we demonstrated the molecular diversity of Lynch syndrome-associated colorectal cancers, showing that different pathogenic pathways going through two distinct types of precursor lesions may lead to colorectal cancer in Lynch syndrome. In the present study, we, together with our collaboration partners from Germany, Finland and the Netherlands, were able to link the molecular diversity of Lynch syndrome colorectal cancer to the clinical picture of colorectal cancer (incidence of adenoma and colorectal cancer) under colonoscopy surveillance.

Our data demonstrate that the observed diversity is associated with the MMR gene affected in the germline, and suggest tailoring the preventive approaches for Lynch syndrome carriers according to pathogenic pathways dominating the carcinogenic process depending on the MMR gene.

The study was performed with grant support of Wilhelm Sander Foundation and German Cancer Aid.