Vivian Cai (@yrv_23) header
Vivian Cai (@yrv_23) profile picture

building @onwardbio events & communities @try_cali

San Francisco, CA
Joined April 2026
Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)Photo by Vivian Cai (@yrv_23)
figured i’d share a little about what we’ve been working on at @onwardbio we started with a simple q- what would it take for AI to actually help cure diseases? give a model a patient’s records from before treatment and ask what happens next; give it results and ask what it would test next, run to see if it was right to do that, you need a scan, a lab result, and a followup note that all belong to the same patient i’m excited about what happens when a model gets something wrong- can we figure out what evidence was missing, go collect it, and see if it does better next time? if you’re building AI for bio, would love to connect let’s cure them all.
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Today we're inviting hospitals, clinics and labs to partner on research We work with frontier labs to connect clinical context, cell level biology, and immune evidence to accelerate drug discovery Email us at onwardbio.ai Let’s cure them all.
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i got a comment yesterday saying i should “stop pretending to be technical and go back to being a honeypot” i started my company @onwardbio because i lost a loved one to cancer, and previously i spent three years doing cancer research across two labs+ coauthored a paper as an undergrad but at the same time i also make time to workout, eat healthy and take care of my appearance, bc these parts of my routine help me mentally clear, feel put together, and motivated in my work and what bothers me is the stereotype that these two things are incompatible
i hate to be the one to say this, but as an asian woman myself, i feel really odd scrolling on x today... seeing other chinese women play into the "honeypot" jokes for views. i know it's meant to be funny, but to me it just reinforces the racist and sexist stereotypes we already deal with, so let's NOT set us back even further by sexualizing ourselves...
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we are working with hospitals and labs starting with thousands of patients' records and expanding across clinical notes, imaging, pathology, molecular data and experimental results & we’re just getting started if you're building Al for bio, would love to chat also hiring across the team- let’s build together :)
figured i’d share a little about what we’ve been working on at @onwardbio we started with a simple q- what would it take for AI to actually help cure diseases? give a model a patient’s records from before treatment and ask what happens next; give it results and ask what it would test next, run to see if it was right to do that, you need a scan, a lab result, and a followup note that all belong to the same patient i’m excited about what happens when a model gets something wrong- can we figure out what evidence was missing, go collect it, and see if it does better next time? if you’re building AI for bio, would love to connect let’s cure them all.
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with matched tumor data, how do you train AI to design cancer vaccines? say we pick CT83 as the antigen & get data to validate against give a model the pretreatment biopsy, make it predict which clones persist, score against the post-treatment specimen it never sees built the harness with claude lol. baselines run, ranking by clone size scores 0.63, reasoning over the expression data gets 0.75 the label is which clones were still there at surgery
designed a TNBC cancer vaccine with claude this weekend picking antigens is the billion dollar question TNBC has low mutational burden, so personalized neoantigens alone leave almost nothing to encode, so need a hybrid approach of ~20 personalized neoantigens plus a shared module a shared shortlist is: CT83: ~65% of TNBC. ZNF165: required for TNBC survival. ACTL8: highest expression of anything screened then I looked for data: everything public is single timepoint. a vaccine has to hit the clones that survive chemo, and one biopsy can't tell you which so I'm building that dataset at @onwardbio matched pre and post treatment tumor, same patient, DNA and RNA
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designed a TNBC cancer vaccine with claude this weekend picking antigens is the billion dollar question TNBC has low mutational burden, so personalized neoantigens alone leave almost nothing to encode, so need a hybrid approach of ~20 personalized neoantigens plus a shared module a shared shortlist is: CT83: ~65% of TNBC. ZNF165: required for TNBC survival. ACTL8: highest expression of anything screened then I looked for data: everything public is single timepoint. a vaccine has to hit the clones that survive chemo, and one biopsy can't tell you which so I'm building that dataset at @onwardbio matched pre and post treatment tumor, same patient, DNA and RNA
New on our Science Blog: How AI is beginning to change scientific modeling. Scientific models help researchers explain and predict real-world systems—like how a single nerve cell fires, or what happens when neutron stars collide. Recent advances have transformed how scientists fit complex models to data. But scientists still typically write the models manually, and usually need to weigh up several competing versions, each of which might explain the data in a different way. In a guest post, Jakob Macke, Daniel Gedon, and Stefan Wahl describe how AI is starting to help with these parts of the process. By writing, running, fitting, and revising scientific models as code, AI can explore many possible model structures, and find out which explanations the data support. anthropic.com/research/teach…
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probably the highest concentration of frontier researchers i’ve ever seen around one dinner table shoutouts @abundant_labs
Had a great time cohosting Reward Snacking Vol. 2 with @yrv_23 at Harborview SF last night! Thanks to everyone who joined us!
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super exciting- biological simulation learning from perturbation data that captures how different cell types respond to drugs and genetic interventions. particularly valuable: single-cell expression profiles paired with crispr knockdowns, compound treatments, immune signals, and experimentally measured outcomes across diverse cell lines and donors.
Replying to @celltypeinc
Biological simulation can be learned. We trained a 27B model in BioSimGym, our RL environments for biology. It outscores the best frontier model on every BioSimBench task.
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when i first learned about cancer vaccines, i was a freshman in high school & the idea felt almost unbelievable now, scientists are finding increasingly fascinating ways to turn cancer against itself a new Nature study introduces FAST, a system that detects abnormal protein translation in cancer cells that triggers gasdermin D production, causing cancer cells to die through pyroptosis while activating anti tumor immune response can we use multimodal models trained on ribosome profiling, RNA-seq, tRNA-seq and proteomics data to predict cancer specific frameshifting events; generative models to design new RNA translation switches; and active learning to prioritize experiments based on predicted outcomes and continuously learn from experimental validation? is what we’re working towards at @onwardbio
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i think one of the most interesting challenges in scientific ai rn is moving beyond models that can answer scientific questions to those that can actually navigate incomplete data, form competing hypotheses, & update experiments when the evidence disagrees with expectations openai also found replacing just 5% of its standard rl training mix with health conversations rewarding honesty, uncertainty and openness to correction improved performance on 17 of 19 non health alignment evaluations how do we train models to recognize when evidence is insufficient? how do we teach them to choose experiments that distinguish between competing hypotheses? i’m particularly interested in how RL and real experimental feedback can help develop these capabilities in medicine at @onwardbio would love to compare notes with researchers in ai bio
We’re sharing how our biology research team worked with Claude to map the first 3D structure of a vault particle from bacterial life. Vault particles are a longstanding mystery. They are barrel-shaped objects, among the largest protein structures found in our cells. They were first discovered by Leonard Rome and Nancy Kedersha in 1986, but their function remains unknown. With Claude, we’ve found results that might bring us closer to solving that mystery. Until now, vaults were only known in the cells of complex things like animals and plants. We have shown that similar proteins from bacteria (and the viruses that infect them) can also assemble into vaults. Finding the structures in these simpler forms of life may make it easier to investigate their function in our own cells. For our life sciences team, the project was also a demonstration of the potential (and the limitations) of using AI to accelerate science. In our full piece, we discuss how Claude was able to dramatically speed up some stages—manually determining the vault particle’s structure would have taken weeks to months of painstaking work, but here it took days. We also discuss how Claude made some simple mistakes along the way, and how we collaborated with our machine learning researchers to address them. Read more: anthropic.com/research/inves…
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chatted with a leading company building benchmarks for protein design then stepped outside to the most beautiful sunrise honestly quite lucky to be alive at this point- we’re getting close to an era where health is basically a software problem and the update cycle gets shorter every day “things that will get solved first are where data’s the most copious, benchmark’s the cleanest, and feedback loop’s the shortest” “our society’s gonna have an abundance of drug candidates, but until you empirically prove them out in clinical trials, that’s gonna be a fundamental bottleneck”-@formationbio as drug discovery gets cheaper, clinical validation and patient data become the bottleneck extremely exciting times ahead.
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3 meetings in and my heart is so full so excited to partner with labs, researchers and clinicians to accelerate patient care & drug discovery so much to build, more soon
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we’re hiring exceptional RL engineers if ur a frontier lab researcher, neolab, data team-would love to compare notes on what models need & how systems can learn from real world feedback to accelerate scientific discovery
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a new study found tumors can escape a cancer vaccine by changing how they display its targets. this is what makes choosing vaccine antigens so difficult. how can we find better targets? one way is thru longitudinal data connecting what’s mutated in the tumor, what immune cells can attack, then track whether that recognition survives as the cancer evolves. nature.com/articles/s41591-0…
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this is the direction we’re building toward > we’re sourcing oncology cohorts with blood, h&e pathology and linked clinical data, exploring patient-matched multi omics and more we also have our own patient cohort, with pre- and post-treatment data collection and longitudinal followup, subject to ethics approval and informed consent the goal is to connect molecular measurements, pathology, treatment, and outcomes from the same patients over time. oncology is our starting point if you’re building medical ai, or interested in a research collaboration, let’s talk
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happy wednesday :) can’t believe its already november hosting a few dinners with friends in yc to celebrate a good year > nov 6: luma.com/tpd3a4l7 > nov 11: luma.com/49a7330u > nov 19: luma.com/k6ukymib
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im no longer gatekeeping this spot- oldschool charm, jazz on vinyl, a perfectly stirred negroni. hosting a night for yc founders, alums & investors to get to know each other over a glass or two. luma.com/tpd3a4l7
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had brunch with a yc founder the other day and my biggest takeaway: sometimes an overnight success is 14 years in the making then i tried his product and it kinda saved me hours of work just on the spot hosting with @agent_relay to talk all things context, if ur a founder deep in multi agent workflows, would love to have u join luma.com/49a7330u
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i think my favorite part of hosting founder dinners in sf is playing matchmaker almost every time, someone comes up and asks “so who should i meet” hosting more yc dinners > luma.com/08r4h66z > luma.com/k6ukymib whether it’s a friend, potential client, business partner, there’s no better way to connect than over good food :)
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scientists built a vaccine to help mice fight breast tumors and live longer it targeted a tiny sugar protein structure on cancer cells the protein, muc1, also exists on healthy cells. but cancer can change the sugars attached to it, exposing a pattern the immune system can recognize now we need to use this difference to stop breast cancer before it becomes invasive in humans the hardest question is: can we teach the immune system to attack early abnormal cells while leaving healthy tissue alone? seeking early breast lesions, matched normal tissue and blood samples to find out
could a vaccine help prevent the most prevalent cancer in women? three years into researching it, this is the question that keeps bringing me back to my desk we’re exploring what that vaccine should target- antigens that appear early, are recognizable to immune cells, and could be targeted without harming healthy tissue which targets persist over time? which disappear? when does the tumor stop presenting them? to investigate, we’re seeking breast tissue sequencing, HLA typing, and matched blood/T cell data across timepoints. early lesions and normal tissue are especially important for evaluating prevention targets if you work at a hospital, lab or biobank with these samples or data, would love to connect
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