Simona Cristea

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Simona Cristea

Simona Cristea

@simocristea

director of applied AI @TempusAI; prev: faculty @DanaFarber, group leader @Harvard & phd @eth

Boston 🇺🇸 & Zurich🇨🇭 Katılım Ocak 2016
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Simona Cristea
Simona Cristea@simocristea·
scRNAseq cell type annotation is notoriously messy. Despite so many algorithms, most researchers still rely on manual annotations using marker genes In a new preprint accepted at ICML GenAI Bio Workshop, we ask if reasoning LLMs (DeepSeek-R1) can help with cell type annotation🧵
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Arc Institute
Arc Institute@arcinstitute·
Three years, same spot, a lot more science 🧬
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Philipp Doc
Philipp Doc@GamerPhilDoc·
@simocristea @NatRevDrugDisc 513 in development, only 33 in Phase III. Immunological barriers like exhaustion and heterogeneity are still the ultimate boss fight.
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Simona Cristea
Simona Cristea@simocristea·
wow as of may 2025, there are 513 cancer vaccines in development, with 33 in phase 3 @NatRevDrugDisc
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José Luis Ricón Fernández de la Puente
I wrote something about the past few days while my mom passed away. It's a tribute to her, my personal memory, and also (even if you don't have any connection to me at all) to satisfy your curiosity about what is it like, to be there during that time.
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Sasha Gusev
Sasha Gusev@SashaGusevPosts·
@simocristea moment of weakness after healthstream went down for maintenance half-way through a video
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Simona Cristea
Simona Cristea@simocristea·
this is the first truly impressive comp bio AI-only analysis that I’ve seen. this is truly useful
Derya Unutmaz, MD@DeryaTR_

As I mentioned before, I am now sharing an example from GPT-5.5 Pro, also featured by OpenAI, that really left me stunned by what it is capable of in biomedical science. (full report on the website I created with Codex, link in the thread). To push GPT-5.5 Pro hard, I uploaded a real data set of immune subset (T cells) gene-expression spreadsheet: 62 sorted T cell samples, 27,906 gene columns, and millions of underlying data points across different T cell subsets. Importantly, this public dataset also had paired structure making it possible to separate true cell-state biology from donor-to-donor variation. I asked GPT-5.5 Pro not merely to summarize the spreadsheet, but to analyze it deeply: What can we learn from this dataset? What are the mechanistic insights? What are the most important biological questions that emerge? What follow-up experiments should we do next? It thought for about 100 minutes and produced a roughly 40-page report! What amazed me was not just the length or even the initial analysis, since previous models are also capable of doing this. What amazed me was the quality of the reasoning and insights it provided! The report recognized that this was not just a table of genes, but two overlapping experimental designs. It identified the major biological axis, which in plain language was that the cells were not just “different categories.” They formed a coherent differentiation landscape, moving from future potential toward immediate function. It also understood the caveats. It did not overclaim from bulk gene-expression data. It clearly explained that bulk transcriptomics cannot distinguish whether every cell in a sorted population has shifted or whether a smaller subpopulation is dominating the signal. It recommended the right next steps experiments, and integration with donor metadata. This is what made the report feel so special to me. It was not just doing statistics. It was reasoning like an expert systems immunologist. It saw the structure of the experiment, interpreted the patterns, built a mechanistic model, identified limitations, proposed causal hypotheses, and laid out a translational roadmap. Other advanced models have been able to generate excellent biomedical reports before, including previous GPT-5 models. So I don't want to claim this is an entirely new type of capability. But this one felt different in an important way. It had more scientific elegance, more restraint, more biological intuition, and more of the nuanced judgment that usually comes only from years of hands-on experience in the field. It felt like this AI model had crossed another threshold. This is the kind of analysis that could easily take a research team months to perform, refine, interpret, and write up. Even then, many teams might not produce something this integrated, this mechanistically coherent, and this useful as a launchpad for future experiments. I know a 40-page T-cell gene-expression analysis may not be exciting to everyone. To illustrate how good it is, also had Codex built a web site with it anyone can explore, link below. 😊 Those interested can go deeper into the report. I also wanted this example on the record because, because to me, it is evidence that we are entering a new stage in AI-assisted biomedical science. The important point is no longer that AI can "analyze data and write a report.” The important point is that AI can now help transform complex biological data into mechanistic understanding, experimental priorities, and testable hypotheses at a speed and depth that would have been almost unimaginable a short time ago. For biomedical science, this is a very big deal! Of course, this may vary across domains, and every analysis still needs expert review, validation, and experimental follow-up. But in my own field, with data I understand deeply, this felt like another inflection point. I feel strongly that we have crossed another milestone threshold in the age of AI, with the release of GPT-5.5.

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Simona Cristea retweetledi
Andrew Gordon Wilson
Andrew Gordon Wilson@andrewgwils·
There's a fourth possibility: humans only appear sample efficient because they've effectively seen a massive amount of data through evolution. Remember, there is a fluidity between the model and the data. The model is a representation of our understanding of data.
Dwarkesh Patel@dwarkesh_sp

There's a quadrillion-dollar question at the heart of AI: Why are humans so much more sample efficient compared to LLM? There are three possible answers: 1. Architecture and hyperparameters (aka transformer vs whatever ‘algo’ cortical columns are implementing) 2. Learning rule (backprop vs whatever brain is doing) 3. Reward function @AdamMarblestone believes the answer is the reward function. ML likes to use pretty simple loss functions, like cross-entropy. These are easy to work with. But they might be too simple for sample-efficient learning. Adam thinks that, in humans, the large number of highly specialised cells in the ‘lizard brain’ might actually be encoding information for sophisticated loss functions, used for ‘training’ in the more sophisticated areas like the cortex and amygdala. Like: the human genome is barely 3 gigabytes (compare that to the TBs of parameters that encode frontier LLM weights). So how can it include all the information necessary to build highly intelligent learners? Well, if the key to sample-efficient learning resides in the loss function, even very complicated loss functions can still be expressed in a couple hundred lines of Python code.

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Sasha Gusev
Sasha Gusev@SashaGusevPosts·
Echoing this experience. I think we are losing the battle against surreptitious AI use in peer review, but I'm begging people who do it to at least check that their AI is not demanding a million laborious analyses that are not actually critical to the conclusions.
alz@alz_zyd_

OTOH, when faced with simple, short papers which make a genuinely novel point, the LLM will sometimes tend to recommend rejection based on the paper not being complicated enough

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Simona Cristea
Simona Cristea@simocristea·
@SashaGusevPosts agree; the most useful now would be to just admit this and let agents interact with agents and humans with humans. imo agent output is suboptimal for direct human consumption but effective for agent consumption
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Sasha Gusev
Sasha Gusev@SashaGusevPosts·
We're rapidly moving towards a world where people voluntarily make their writing worse so that it doesn't get filtered out in an AI screen.
Nav Toor@heynavtoor

Researchers sent the same resume to an AI hiring tool twice. Same qualifications. Same experience. Same skills. One version was written by a real human. The other was rewritten by ChatGPT. The AI picked the ChatGPT version 97.6% of the time. A team from the University of Maryland, the National University of Singapore, and Ohio State just published the receipt. They took 2,245 real human-written resumes pulled from a professional resume site from before ChatGPT existed, so the human writing was actually human. Then they had seven of the most-used AI models in the world rewrite each one. GPT-4o. GPT-4o-mini. GPT-4-turbo. LLaMA 3.3-70B. Qwen 2.5-72B. DeepSeek-V3. Mistral-7B. Then they asked each AI to pick the better resume. Every model picked itself. GPT-4o hit 97.6%. LLaMA-3.3-70B hit 96.3%. Qwen-2.5-72B hit 95.9%. DeepSeek-V3 hit 95.5%. The real human almost never won. Then the researchers tried the obvious objection. Maybe the AI is just better at writing. So they had real humans grade the resumes for actual quality and ran the experiment again, controlling for it. The result was worse. Each AI kept picking itself even when human judges rated the human-written version as clearer, more coherent, and more effective. It gets worse. The AIs do not just prefer AI over humans. They prefer themselves over other AIs. DeepSeek-V3 picked its own resumes 69% more often than LLaMA's. GPT-4o picked its own 45% more often than LLaMA's. Each model can recognize and reward its own dialect. Then the researchers ran the simulation that ends careers. Same job. 24 occupations. Same qualifications. The only variable was whether the candidate used the same AI as the screening tool. Candidates using that AI were 23% to 60% more likely to be shortlisted. Worst gap was in sales, accounting, and finance. 99% of large companies now run AI on incoming resumes. Most of them use GPT-4o. The paper just proved GPT-4o picks GPT-4o 97.6% of the time. If you wrote your own cover letter this week, you did not lose to a better candidate. You lost to a worse candidate who paid OpenAI 20 dollars. Your qualifications do not matter if the AI prefers its own handwriting over yours.

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Simona Cristea
Simona Cristea@simocristea·
@jeremyli__ @AlexTISYoung i think human+agent baseline is the real test with very high potential. i also think 30% on these tests is quite impressive
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Jeremy
Jeremy@jeremyli__·
@AlexTISYoung hopefully in v2 we can construct some human/human-agent baselines against which to compare
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Simona Cristea
Simona Cristea@simocristea·
I learned so much from Brian, he is such an empathetic & knowledgable oncologist, and a great leader. Brian’s research spans the whole spectrum of pancreatic cancer efforts, from prevention, diagnosis, up to late-stage treatment; this work here is only one piece of the puzzle 👏
Dana-Farber News@DanaFarberNews

Pancreatic cancer research at #AACR26: Dr. Brian Wolpin of @DanaFarber_Hale presents encouraging data on safety and efficacy from a small study combining the RAS inhibitor daraxonrasib with chemotherapy in patients with advanced #PancreaticCancer. @danafarber ➡️bit.ly/4cAoXMU

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Specialsituationz
Specialsituationz@hannibalspeaks·
To be honest the biggest generational breakthrough in oncology has been immunotherapy. The power of redirecting the innate immune system can not compare to molecular targeting of any oncogene under selection pressure. Even CART is more impressive.
Chaotropy@chaotropy

Remember when it was still an open question whether the undruggable could be drugged? Six years later, @RevMedicines has drugged the undruggable, and how they drugged it. What a time to be alive, what a time to practice! $RVMD

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Simona Cristea
Simona Cristea@simocristea·
interesting word cloud then&now, makes me reflect on how there’s less focus now on subclonal reconstruction than 5y ago. while unfortunate that tumor progression is not that researched anymore, maybe that’s progress: we accepted subclonality & now need to focus more on therapies
Linghua Wang, MD, PhD@IamLinghua

✈️ back from #AACR26 inspired and grateful. I haven’t missed an AACR Annual Meeting since 2012 and it remains my favorite. Grateful for the chance to speak and for the highly engaged audience at our team's talks and posters. Joy to reconnect with friends, colleagues and new faces

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Anirban Maitra
Anirban Maitra@Aiims1742·
Well if that isn’t the perfect encapsulation of #AACR26
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Simon Barnett
Simon Barnett@SimonDBarnett·
Can someone explain to me why the ‘LLMs are conscious’ debate is trending again? Who cares? It’s obviously a fun philosophical question. I’m glad it occupies late-night conversations and even board discussions. But people seem to clutch onto ‘LLMs can’t reason’ like geocentrism. It’s as if admitting that weights and biases can mimic reasoning-like acts is somehow debasing our species — like losing our privileged position in firmament. LLMs are a tool. Increasingly, this tool is becoming capable of multi-hop, complex tasks that previously could only be traversed by our mush-brains — not cold, unfeeling mat-muls. I don’t get the productivity of the consciousness conversation insofar as it doesn’t map cleanly to what the tools can or cannot do. It seems like a dangerous bet to underestimate these systems.
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