Dr. Jean Fan

Dr. Jean Fan

@jef.works

Associate prof comp biologist @JHUBME. Founder @cuSTEMized. Editor @PLOSCompBiol. Alum @HarvardDBMI @blairmagnet. Doing art like a science, science like an art.

2.4K followers73 following173 posts

In this blog post, I put our new faster implementations of STalign + STcompare to the test! I align 200k spatially resolved single cells + perform spatial differential expression analysis in < 1 minute. Try it out for yourself: jef.works/blog/2026/10...

Our paper on computational method STARIT using computer vision AI analysis of spatial transcriptomics data for unsupervised characterization of subcellular heterogeneity is now published ๐Ÿฅณ ๐Ÿ—ž๏ธ: journals.plos.org/ploscompbiol... ๐Ÿ’ป: github.com/JEFworks-Lab... Congrats to Dee Velazquez and team ๐Ÿ‘ ๐Ÿฅณ

journals.plos.orgSpatial Transcriptomics As Rasterized Image Tensors (STARIT) characterizes cell states with subcellular molecular heterogeneityAuthor summary Imaging-based spatial transcriptomics technologies can map the locations of individual RNA transcripts within cells, providing an opportunity to study how genes are spatially organized ...

Using real imaging-based spatial transcriptomics (MERFISH) data of bacteria, STARIT identifies cells with similar overall exp magnitude but distinct subcellular organization: showing more punctuated vs diffuse transcript localization for flagellar subunits, with potential functional consequences.

By providing an alternative representation of molecular-resolution spatial transcriptomics data, we hope STARIT will enable the identification of novel cell-states. Congrats to Dee Velazquez for leading this work ๐Ÿ‘ ๐Ÿฅณ STARIT is available as a Python package. Try it out: github.com/JEFworks-Lab...

github.comGitHub - JEFworks-Lab/STARIT: Spatial Transcriptomics As Rasterized Tensors (STARIT)Spatial Transcriptomics As Rasterized Tensors (STARIT) - JEFworks-Lab/STARIT

Imaging-based spatial transcriptomics is often represented as cell-level gene counts, overlooking subcellular spatial variation. STARIT creates an image-based representation, allowing us to use computer vision AI models to identify cell states with distinct subcellular localization patterns.

In this updated preprint, we show STARIT can delineate smooth trajectories with continuous changes in subcellular localization, is robust to partial volume capture under certain conditions, and is compatible with a range of AI feature extractors.

Our paper on spatial transcriptomic profiling of cold ischemia in mouse kidneys is now published open-access in Genome Biology: link.springer.com/article/10.1... We hope these insights help us understand cold-storage injury in kidney transplants + inform future temporal ST analyses. Congrats team ๐Ÿฅณ

I'm currently running the most sophisticated agentic network (pregnancy). Within the span of 40 weeks, my biological agents (cells) will read 3 billion letters of instructions (DNA) to autonomously assemble a new human being. When will AI agents catch up? ๐Ÿ˜‰ #biologyisamazing

Check out our updated preprint on STcompare w/ more benchmarks vs other spatial transcriptomics comparison methods, demo robustness to alignment error, etc. Preprint v2: www.biorxiv.org/content/10.1... New tutorials: jef.works/STcompare/in...

biorxiv.orgSTcompare: comparative spatial transcriptomics data analysis of structurally matched tissues to characterize differentially spatially patterned genesMotivation Comparative analysis of spatial transcriptomics (ST) data is needed to identify genes that spatially change in their expression patterns between conditions, such as in diseased versus healt...
Dr. Jean Fan@jef.works

Check out our new preprint on STcompare for identifying spatially differential gene expression patterns at structurally matched locations across spatial transcriptomics datasets. Preprint on bioRxiv: www.biorxiv.org/content/10.1... R package on Github: github.com/JEFworks-Lab... #AcademicSky ๐Ÿงต๐Ÿ‘‡

Many of us profs are struggling w/ AI use by students. But a source of frustration I didn't anticipate: AI use by colleagues. Because if I had wanted an AIโ€™s opinion, I too can prompt ChatGPT ๐Ÿ™„ More in my reflection on "Artificial Intelligence among University Professors" jean.fan/2026/07/16/a...

Happy 20th birthday to PLOS Computational Biology ๐ŸŽ‚ In this perspective, as an editor for the Genomics section, I offer a data-driven reflection on how genomics research within the journal has evolved over the years by analyzing trends in submitted research papers: journals.plos.org/ploscompbiol...

journals.plos.orgAnother 10 years of PLOS Computational Biology: A data-driven reflection on trends in genomics researchSince the founding of PLOS Computational Biology 20 years ago, genomics research has advanced at a remarkable pace. In this 20th anniversary commentary, as an Editor for the Journal Section of Genomic...

In this blog post, I demo how I went from a question โžก๏ธ "how have gas prices changed in different regions across the US over time?" โžก๏ธ to using AI to find relevant data โžก๏ธ to using AI to vibe code this data visualization to answer my question: jef.works/blog/2026/05... Try it out for yourself!

Before cameras, only painters could "capture reality." After, people said cameras would replace painters. But painting evolved. Now, people say AI will replace programmers. So, I reflect on things painting in the age of cameras can teach us about coding in the age of AI: jean.fan/2026/04/22/a...

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Our spatiotemporal transcriptomic analysis thus identified coordinated molecular changes within metabolic pathways deep within the cold ischemic kidney, highlighting potential opportunities for new insights beyond those available from superficial biopsy-focused tissue examinations.

Increased durations of cold ischemia is implicated in poor transplant outcomes, but the molecular mechanisms remain unclear. Using spatial transcriptomics, we profiling cold ischemia injury using a mouse model to identify temporally-resolved gene expression changes in a compartment-specific manner.

Our spatiotemporal molecular analysis reveals an unexpected metabolic response: genes involved in oxygen-dependent oxidative phosphorylation are upregulated in the hypoxic inner medulla, a region that typically relies on glycolysis. Now corroborated by protein-level evidence from immunofluorescence.

Check out this article from TheScientist profiling our development of the Mentorship Index as a proxy for a researcherโ€™s contribution to mentoring junior scholars The M-Index: A New Metric Puts Mentorship in the Spotlight the-scientist.com/the-m-index-... Calculate yours: jef.works/Mentorship-I...

the-scientist.comThe M-Index: A New Metric Puts Mentorship in the Spotlight | The ScientistThe Mentorship Index aims to provide a quantifiable proxy of how researchers support junior scientists, offering a new way to evaluate academic impact.
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The M-index isnโ€™t meant to replace holistic evaluation of mentoring abilities. But such metrics can help surface something I care about in ways that existing metrics like the h-index doesnโ€™t capture. If we donโ€™t create metrics that reflect our values, we cede that ground to metrics that may not.

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My approach: I use openalex.org to count the # of publications for which the scientist served as last author (senior/mentoring role) where the first author (the mentee who led the work) was relatively new to science (proxied by the # of publications associated with their name at that time).

openalex.orgOpenAlex

To put this Mentorship Index to the test, I applied it to evaluate 2 colleagues ๐Ÿ˜œ h-index: Manolis wins (170 vs 88) M10-index: Lior wins (106 vs 38) Both have invested in achieving different kinds of accomplishments, which can be reflected in these different metrics.

We're recruiting senior faculty! So at faculty meeting, a colleague brought up a candidate who has an h-index of 100. Impressive! But then another colleague pointed out: their last senior-author paper was 10 years ago. This got me thinking about what metrics actually capture and what they miss.

So what do we care about in a senior faculty recruit? For me: mentorship of junior scientists (not just recruiting already-polished senior postdocs). But how do we quantify that?

We previously showed how changing training data alone can improve deep learning prediction of spatial transcriptomics gene expression from histology images by +38% (without any changes to model architecture). We've now updated our preprint w/ expanded results: www.biorxiv.org/content/10.1... ๐Ÿงต1/n

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We've now updated our preprint to expand on these results to further demonstrate that these data quality-driven effects are reproducible across: โœ… More spatial transcriptomics datasets โœ… More spatial transcriptomics technologies โœ… Different feature extractors โœ… Alternative model architectures 3/n

Check out our preprint with more details, quantifiable metrics, insufficiencies of data imputation, and other insights: www.biorxiv.org/content/10.1... Work led by Caleb Hallinan ๐Ÿฅณ 4/4 Previous thread: bsky.app/profile/jef....

biorxiv.orgbiorxiv.org
Dr. Jean Fan@jef.works

High costs motivate efforts to predict spatial transcriptomics from H&E images w/ deep learning. In our recent preprint, we show that noise, sparsity & resolution in ST data impact performance, highlighting the importance of training data quality: www.biorxiv.org/content/10.1... ๐Ÿงต1/n

We previously showed how changing training data alone can improve deep learning prediction of spatial transcriptomics gene expression from histology images by +38% (without any changes to model architecture). We've now updated our preprint w/ expanded results: www.biorxiv.org/content/10.1... ๐Ÿงต1/n

We previously showed how improving data quality (molecular detection sensitivity, imaging resolution, etc) provides an orthogonal strategy to tuning model architecture in spatial transcriptomics-based predictive modeling. But data imputation intended to improve data quality led to overfitting. 2/n

In this blog post, I vibe code to apply STcompare to kidneys assayed by two different spatial transcriptomics technologies (Visium vs. Xenium) to identify spatially consistent and differentially patterned genes. Follow along + try it out for yourself: jef.works/blog/2026/02...

We recently updated our paper demonstrating evidence of off-target probe binding affecting the 10x Genomics Xenium spatial transcriptomics platform with key clarifications, new quantifications, and approaches for evaluating custom gene panels: biorxiv.org/content/10.1... ๐Ÿงต๐Ÿ‘‡1/n

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By shedding light on off-target probe binding + providing a tool to enable prediction, we hope this work will enhance the quality of + improve reproducibility in spatial transcriptomics research ๐Ÿ™Œ Caleb Hallinan + team Previous post: bsky.app/profile/jef....

Dr. Jean Fan@jef.works

We identify evidence of off-target probe binding in the 10x Genomics #Xenium v1 Human Breast Gene Expression Panel, compromising the accuracy of resulting #singlecell #spatialtranscriptomics profiles See our preprint for more details: www.biorxiv.org/content/10.1... #AcademicSky ๐Ÿงต๐Ÿ‘‡ 1/n

We recently updated our paper demonstrating evidence of off-target probe binding affecting the 10x Genomics Xenium spatial transcriptomics platform with key clarifications, new quantifications, and approaches for evaluating custom gene panels: biorxiv.org/content/10.1... ๐Ÿงต๐Ÿ‘‡1/n

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Finally, we emphasize that such off-target binding may similarly affect other probe-based gene detection approaches from other commercial vendors given sensitivity vs. specificity tradeoffs. We therefore emphasize the importance of transparency through sharing probe sequences.

We recently updated our paper demonstrating evidence of off-target probe binding affecting the 10x Genomics Xenium spatial transcriptomics platform with key clarifications, new quantifications, and approaches for evaluating custom gene panels: biorxiv.org/content/10.1... ๐Ÿงต๐Ÿ‘‡1/n

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We now clarify the differences between these probe sequences in a new supplementary note. Importantly, this impacts our interpretation of observed results to provide stronger evidence of putative imperfect sequence homology based off-target probe binding.

We also now demonstrate how to leverage tissue-specific gene expression from atlasing resources like HuBMAP to assess how off-target binding might affect observed gene expression profiles in a specific tissue of interest for custom gene panels.

We recently updated our paper demonstrating evidence of off-target probe binding affecting the 10x Genomics Xenium spatial transcriptomics platform with key clarifications, new quantifications, and approaches for evaluating custom gene panels: biorxiv.org/content/10.1... ๐Ÿงต๐Ÿ‘‡1/n

Previously, we used the publicly available Xenium v1 Human Breast Panel probe sequences from the 10x website (pre-April 2025). We now understand that this file erroneously included extra probe sequences that aren't actually used.