People

John Maciejowski, PhD

John started the lab in 2017. He works on how genomic instability shapes cancer genomes and on how cancer cells manage the immune consequences of their own instability. He teaches chromosome structure at Gerstner Sloan Kettering and the nuclear envelope at Weill Cornell.

He did his PhD at MSKCC in the inaugural class at the Gerstner Sloan Kettering Graduate School, working with Prasad Jallepalli on the mechanisms that keep chromosome segregation accurate during mitosis. He then joined Titia de Lange's lab at Rockefeller University, where he found that telomere dysfunction gives rise to complex clusters of chromosome rearrangement and hypermutation. He is an Associate Member of the Molecular Biology Program at SKI and an Associate Professor at Gerstner Sloan Kettering and in the Weill Cornell BCMB program.

He also spends time with his family.

Eleonore Toufektchan, PhD

Eleonore studies how chromosomally unstable cancer cells develop the means to evade the immune system. She built the lab's protocol for purifying micronuclei, and she sets up and leads the animal work, which is where most of our questions about tumors and immunity eventually have to be answered. She has been in the lab since 2019.

Eleonore is originally from France. She has a bachelor's degree in biochemistry from the University of Lyon and a master's in molecular and cellular biology from University Pierre and Marie Curie in Paris. She did her PhD at the Curie Institute on the role of p53 in bone marrow failure syndromes, where she showed that p53 is a major regulator of the Fanconi anemia DNA repair pathway and traced telomere dysfunction in a family of Dyskeratosis congenita patients to a germline mutation in the p53 regulator Mdm4. Her postdoctoral work was supported by a Monahan Fellowship from the JLM Fund.

Outside the lab she does a lot of arts and crafts, including embroidery and ceramics, and recently became an associate artist at her pottery studio. She also bakes, keeps plants, and plays with her cats.

Amer Hossain, PhD

Amer works on extrachromosomal DNA, the circular DNA bodies that carry amplified oncogenes in many cancers. ecDNA have no centromeres, so nothing obvious should stop them from being lost when a cell divides, and yet they are inherited reliably. Amer is working out what physically holds them to chromosomes during mitosis and what protects them from ending up in the cytosol.

Amer is from Dhaka, Bangladesh, and moved to the United States in 2010 to study biochemistry and economics at Vassar College. After working as a research assistant in Boston on the genetics of neurodevelopmental disorders, he came to New York in 2016 for his PhD at Rockefeller University with Luciano Marraffini, where he studied DNA repair proteins in host-virus conflicts in bacteria. He showed that bacteriophage-encoded recombination systems let phages evade bacterial CRISPR-Cas immunity, and he discovered a new family of DNA glycosylases that provide antiviral defense. He joined the lab in 2024 and is supported by a fellowship from the Jane Coffin Childs Memorial Fund.

Outside the lab Amer plays soccer, eats at as many restaurants as he can, and likes the sights, sounds, and crowds of New York, which remind him of his hometown.

Marton Kovacs, PhD

Marton works on how DNA damage and genomic instability change the structure of the nucleus, and on how that structural damage feeds into innate immune regulation. He is interested in how different compartments of the cell, mainly the nucleus and the ER, communicate under these conditions.

Marton is from Hungary. He has a bachelor's degree in biology from Eotvos Lorand University in Budapest and a master's in molecular biology and genetics from the University of Copenhagen, where he worked with Michael Lisby on the helicase ZGRF1/Mte1 and was first introduced to genomic instability. He did his PhD with Raphael Ceccaldi at the Institut Curie in Paris, describing how DNA damage can lead to nuclear envelope rupture and how that might be a cancer vulnerability. He joined the lab in February 2024 and is supported by an Eliasoph Postdoctoral Research Fellowship.

Outside the lab Marton hikes, goes to exhibitions with a preference for modern art, and reads fantasy and science fiction.

Roshan Norman, PhD

Roshan works on how genomic DNA ends up in the cytosol of cancer cells in the first place. Cytosolic DNA is what the innate immune system detects, so the routes by which it gets there determine a lot about which tumors are visible to the immune system and which are not.

Roshan grew up in Kerala, in southern India, and did his undergraduate studies at the Indian Institute of Science in Bangalore, where he worked on peptide inhibitors of Protein Phosphatase 1 at the Molecular Biophysics Unit. He did his PhD with Mark Burkard at the University of Wisconsin-Madison on Polo-like kinase 1 signaling in mitosis and its role in protecting the centromere, where he found a previously uncharacterized dynamic localization of Plk1 to the inner centromere. He also developed a 3D isotropic expansion microscopy method to image Plk1 at nanometer resolution. He joined the lab in February 2024.

Outside the lab Roshan plays volleyball and tennis and hikes in state and national parks with friends.

Abe Shim

Abe studies how the exonuclease TREX1 suppresses cGAS-STING signaling. He is dissecting which parts of the TREX1 protein are required, and looking at whether autophagy-related factors are involved in the process.

Abe grew up in Seoul and in Washington State and has a BS in molecular biophysics and biochemistry from Yale. He started research in the Myler lab at Seattle Children's working on a high-throughput protein purification pipeline for structure determination, and did his main undergraduate work in the Gomez lab at Yale School of Medicine using Nanopore sequencing to study microRNA-driven transcriptomic regulation in neutrophilic asthma. As an Amgen Scholar he spent a summer on cancer epigenetics in the Lu lab at Columbia. He joined the lab in 2021 and is supported by an F31 fellowship from NIAID.

Outside the lab Abe reads a lot, window shops for fragrances and skincare, takes hiking trips, and stays unusually well informed about local news.

Josefine Striepen

Josefine works on APOBEC3A, an enzyme that is one of the largest sources of point mutations in human cancer despite being almost undetectable in most measurements of tumors. She found that it switches on inside a rare and short-lived cell state that resembles squamous differentiation, and that cancer drugs can push cells into that same state. She is now working out what controls entry into it.

Josefine is originally from Athens, Georgia, and earned her BA at Bryn Mawr College. She then worked as a technician in David Fidock's lab at Columbia on drug resistance in the malaria parasite P. falciparum. She joined the lab in 2021 and is supported by an F31 fellowship from the NCI.

Outside the lab Josefine is either on a dance floor or planning the lab's next social event. Past examples include taco nights, cookie decorating, pumpkin carving, and lab coat tie-dying.

Hannah Rosenberg

Hannah works on TREX1 and how it suppresses innate immunity. She is interested both in the mechanism and in what it would take to target the enzyme therapeutically in cancer.

Hannah is from Flemington, New Jersey, and has a BS in chemistry from the University of Pittsburgh, where she did chemical biology research in Alex Deiters' lab. She spent a summer in the Hammond lab at the University of Utah using RNA-based tools to study small molecules, including cGAMP, which remains her favorite one. She joined the lab in 2024.

Outside the lab Hannah runs in Central Park, works through the city's bagel places, and spends time with friends.

Adonis John

Adonis keeps the lab running, which is closer to herding cats than the title suggests. She places orders, organizes equipment purchases and maintenance, arranges travel and conferences, and keeps morale up. We would be nothing without her.