Hélène Ruffieux, PhD

I am a Senior Research Fellow and Team Leader at the MRC Biostatistics Unit, University of Cambridge (United Kingdom). I hold a PhD in Mathematics from EPFL (Switzerland). My research lies at the intersection of statistical methodology and its application to open problems in biomedicine.

My team develops Bayesian methods and accompanying software, with a focus on scalable hierarchical modelling approaches for variable selection, latent structure discovery and network estimation, in high-dimensional or temporal data settings. Our methods are motivated by research questions arising from collaborative clinical and biological studies. Our overarching goal is to provide principled statistical and computational tools to help advance our understanding of the biological processes driving disease risk and progression.

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Team

I have the pleasure of working with talented researchers at the MRC Biostatistics Unit:

  • Xiaoyue Xi, Research Associate;
  • Daniel Temko, Research Associate;
  • Marion Kerioui, Research Associate;
  • Yiran Li, PhD Candidate (co-advised with John Whittaker and Sylvia Richardson);
  • Joseph Feest, Research Assistant.

Former team members:

  • Camilla Lingjærde, PhD Candidate & Research Associate until May 2024, co-advised with Sylvia Richardson, now Research Fellow at the University of Oslo.

I also regularly supervise Bachelor and Master theses of students from Cambridge University and EPFL (Lausanne), and I am a co-organiser of the MRC Biostatistics Unit Internship Programme.

Recent activity

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Nov 5, 2024: Our manuscript on a variational Bayesian approach for multivariate functional principal component analysis has now been accepted for publication the Journal of Computational Statistics & Data Analysis ! Joint with Tui Nolan and Sylvia Richardson.

Oct 15, 2024: The research of the team will be highlighted at the London CFE-CMStatistics Conference in December, with talks by Xiaoyue Xi and myself (programme).

Aug 7, 2024: Our Joint Graphical Horseshoe approach has just been published in the Annals of Applied Statistics! Joint with Camilla Lingjaerde, Benjamin Fairfax and Sylvia Richardson.

Jun 25, 2024: Our work on leveraging node-level information for Bayesian network inference has now been published in Biostatistics ! Lead Author: Xiaoyue Xi.

May 31, 2024: Joseph Feest, third year student at Cambridge University (and former summer intern in the team) has successfully completed a year-long project part of his degree, supervised by Xiaoyue Xi and Camilla Lingjaede. Congratulations to him !

Research

The landscape of biomedical research is changing rapidly, driven by technological advances for quantifying clinical and molecular data at scale. This evolution not only offers a more granular view of disease mechanisms, but also parallels a growing acknowledgment that pathogenic responses are tightly coordinated at the organismal level. Consequently, there is a need for modelling approaches capable of providing a holistic understanding of complex interplays across biological systems.

My team aims to provide principled statistical methodology for tackling this challenge, guided by collaborations with clinicians and researchers in areas such as immunology, infectiology and cancer. Specifically, we develop Bayesian hierarchical modelling approaches for sparse regression, graphical modelling, latent factor modelling and functional data analysis to leverage complicated dependences within and between heterogeneous biological data sources (e.g., genetics, genomics, proteomics, metabolomics), while conveying uncertainty coherently.

We are particularly interested in addressing the tension between flexible joint estimation and practical feasibility for analysis at the scale of current biomedical studies, through dedicated efforts to enhance accuracy, robustness and computational tractability. Common threads for our methods include (i) uncovering and leveraging shared biological structures across multiple contexts (molecular entities, tissues, cell types or disease subtypes), and (ii) using approximate inference procedures, such as expectation-maximisation (EM) and model-specific variational schemes, tailored to the exploration of multimodal parameter spaces.

Our methods are designed with specific contexts in mind, yet are adaptable for various scientific applications, which is facilitated by accompanying statistical implementations (see Software).

Our research receives generous support from the Lopez–Loreta Foundation.

Short bio

Awards

Software & code

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atlasqtl

Variable selection in sparse regression with hierarchically-related responses

bayesFPCA

Bayesian functional principal component analysis suite – with Tui Nolan

book chapter on Bayesian variable selection

Source code for reproducing an example in a chapter published in the Handbook of Bayesian variable selection

covid patient trajectories app

FPCA estimates of patient disease trajectories after SARS-CoV-2 infection

covid recovery prediction app

Prediction of incomplete recovery from COVID-19

echoseq

Faithful replication and simulation of molecular and clinical data

epispot

Annotation-driven approach for large-scale joint regression with multiple responses

jointGHS

Joint graphical horseshoe for multiple network inference with shared information – creator and maintainer Camilla Lingjærde

locus

Large-scale variational inference for variable selection in sparse multiple-response regression

masterclass in variational inference

Solutions and suggested code for the 1st practical session fo the Bayes4Health-CoSInES Masterclass in variational inference – with Camilla Lingjærde

mQTL analysis example

Source code for reproducing a numerical example using the method “locus” on simulated data

navigm

Variable-guided network inference using Bayesian graphical spike-and-slab modelling – creator and maintainer Xiaoyue Xi

searchable pQTL database

Online database gathering hits from a QTL mapping of human protein abundance in plasma

sensitivity analysis for atlasqtl

Source code for assessing the sensitivity of the method “atlasqtl” to hyperparameter settings

software corner IBS bulletin

Source code for reproducing article on the atlasqtl R package published in the Software Corner of the IBS Bulletin

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