Dr Aniel Sanchez has spent his career following the science wherever it leads, rebuilding his thinking each time it takes him somewhere new. From a chemistry lab in Havana to a postdoctoral position in Rio de Janeiro, a research leadership role at one of Scandinavia’s most ambitious cancer programmes, and now the frontier of proteoform-centric medicine at Northwestern University, each chapter of his career has demanded not just new techniques but a new way of seeing.

Along the way, he developed a philosophy about science that openness to unexpected results is a precondition for good science and learning to enjoy the process tends, in the end, to lead to better work. Now, as part of the Neil Kelleher group, Aniel is helping to push proteomics into territory that has long been out of reach: the systematic, large-scale characterisation of proteoforms, the distinct molecular variants of proteins that may hold far more biological information than conventional protein-level measurements have ever been able to capture.

From classical protein chemistry to modern proteomics

Aniel’s career has spanned paradigm shifts in what proteomics can do, which has required significant shifts to his own approach. As an undergraduate studying chemistry and bioinformatics at the University of Havana, Aniel trained under Gabriel Padrón and Lila Castellanos – pioneers of proteomics in Cuba – alongside a next generation of researchers including Luis Javier González, Vladimir Besada, and Lazaro Betancourt. Cuba was, at the time, home to one of the first mass spectrometers in Latin America, and the group was transitioning from classical protein chemistry into modern proteomics, integrating mass spectrometry and chromatography as core analytical tools.

By the time the group had a QTOF, it was well-suited to the work of the moment, but as ion traps and Orbitraps emerged, the thinking had to change alongside the technology. What you can see in science, Aniel came to understand, depends entirely on the instrument you see it with – and the state of the art is always in motion.

The method and the mentor

Coming into proteomics from the technical side, Aniel’s instincts first ran toward the ‘small picture’: what kind of sample, how many proteins could be extracted, which method to apply. But working alongside collaborators who came from the biology side and thought in bigger terms, about the problem being solved, the clinical question at stake, introduced him to what he describes as a different language. Over time, he became fluent in both and moves between the two depending on the audience. Speaking with family or friends, for example he reaches naturally for the big picture; in scientific conversation, his mind often returns to the small. That tension, he reflects, has always driven him forward:

“My interest evolved from identifying proteins to improving the methods themselves, always aiming to extract deeper, more reliable biological information from proteomic data.”

It was in Brazil, during his first postdoctoral position at the Federal University of Rio de Janeiro, that this instinct for the technical met its most formative counterweight. Under Professor Gilberto Domont, Aniel’s work focused on improving peptide identification through orthogonal metrics alongside conventional approaches. But it was the mentor, more than the method, that left the deeper impression. Domont is considered by many to be the defining reference point in the history of proteomics in Brazil and one of the longest-standing active members of HUPO. Well into his late eighties and nineties, he continued applying for funding, delivering lectures, and teaching courses on the history of the discipline.

Aniel sees him as a philosopher-scientist: Domont’s outlook rests on a simple premise: you cannot change nature, only observe it. Facts are facts. Error, when it occurs, is on the side of the researcher, which means the answer to any experimental problem begins with openness, not assumption. Be willing to receive results that differ from what you expected or hoped for, and that willingness will make you not only a better scientist but a happier one. Even when confronted with a large and intractable problem, Domont’s instinct was to ask about the smallest things first: are the solvents correct? Are the lines right? Details that seem trivial, but that quietly govern everything. Aniel has found Domont’s approach more useful the further his career has taken him:

“Be rigorous and serious about the work, but always remain enthusiastic and enjoy the process.”

In other words, slow down, step back, have a coffee. The science will still be there. And there’s always a place for both the big picture and the small picture.

ReproUnion, European Cancer Moonshot, and the Scandinavian biobank

Aniel’s path from Rio to Sweden was shaped by an earlier and independent initiative in reproductive medicine, led by Professor Aleksander Giwercman, with proteomics efforts supported by Professors György Marko-Varga and Johan Malm at Lund University. A cross-border collaboration between Sweden and Denmark, later known as ReproUnion, was already taking form, aiming to tackle infertility and related conditions. It was this project that first brought him to Lund, drawn by the opportunity to apply high-resolution protein analysis to a different domain of human health.

Testosterone deficiency (hypogonadism) is associated with a range of serious comorbidities, including metabolic syndrome and type 2 diabetes. Yet despite this significance, reliable biomarkers of androgen activity in humans remain limited, highlighting an important gap in both diagnosis and treatment. Although reproductive medicine has not always been perceived with the same urgency as more immediately life-threatening diseases, its complexity and long-term health implications underscore the need for deeper molecular understanding – an area where proteomics, with its capacity to capture systems-level biological responses, is particularly well placed.

To address this, thirty healthy young male volunteers underwent pharmacological suppression of testosterone using a GnRH antagonist – the same agent used clinically in prostate cancer treatment – followed by controlled testosterone supplementation and longitudinal monitoring during recovery. The results revealed a set of candidate biomarkers more closely tied to downstream metabolic effects than testosterone concentration alone. Beyond identifying new markers, the study pointed to a deeper insight: measuring downstream protein responses may better capture androgen activity than hormone concentration itself. It is precisely this kind of insight that, in Aniel’s view, demonstrates what proteomics and systems biology can offer that conventional approaches cannot.

At Lund, Aniel would also go on to lead a small team under Professors György Marko-Varga and Johan Malm within the framework of the European Cancer Moonshot. The scale of collaboration was unlike anything he had previously worked within: multiple countries contributing, the former president of HUPO, Mark Baker, among those involved, and Lund University itself embedded within one of the most extensive academic biobanking infrastructures in Scandinavia.

Alongside this, Aniel contributed to what would become the MM500 initiative – to date the largest melanoma proteomics atlas in existence. Spanning 505 tumour samples taken from 26 organs across 232 patients, the study mapped protein levels, localisation, and modifications across a broad spectrum of malignant melanoma, identifying more than 15,500 proteoforms by mass spectrometry and covering 72% of the proteins in the high-stringency blueprint of the human proteome. Clinical outcomes, biomarker discovery, and patterns of therapeutic response were woven through the molecular characterisation. The infrastructure underpinning this work (snap-freezing, automated fractionation, digital traceability, integrated multi-omics pipelines) represented a model for what rigorous, large-scale translational proteomics could look like.

‘Renovating’ the self

Each of Aniel’s moves has required not just a change of place but a rethinking of approach. His career arc spans intact protein analysis, targeted peptide strategies, translational clinical proteomics, and now the rapidly evolving frontier of proteoform-centric medicine. Moving countries only added to his need to move between ways of thinking; for the first time, he encountered researchers who approached problems differently and didn’t share his assumptions. Some worked extraordinarily hard but struggled when results did not follow; wearing themselves down, unable to separate a failed experiment from a judgement of themselves. This pattern taught him that emotional intelligence and resilience are as central to research as the technical skills.

He also came to see competition differently. The question, as Aniel frames it, is not whether competition exists but whether you engage with it healthily. Through conversation, agreement, and a disposition toward generosity, he found that competition could often be converted into collaboration – that helping others move forward tended, over time, to move everyone forward. The enemy is the question you are both trying to answer.

Networking, for Aniel, connects to the same thread. Many researchers treat it primarily as a means to an end: finding positions, securing funding, opening institutional doors. He sees it differently. In professional life, honest and sometimes uncomfortable feedback is far rarer than in personal relationships, yet it’s exactly what scientific growth requires. A broad network of diverse colleagues provides something closer to that: perspectives that unsettle assumptions, critiques that might sting a little but ultimately point somewhere useful. Networking, in his view, builds the emotional readiness to receive a heavily annotated peer review and grow from it, rather than becoming destabilised. He would encourage his younger self to invest in it earlier – not as a career strategy, but as a form of scientific resilience.

The next frontier

It was a long-standing interest in proteoforms that drew Aniel to his current position in the Neil Kelleher group, and the connection to his earliest training is direct.

“My early training focused on intact protein analysis,” he explains, “and the complexity inherent to proteoforms naturally drew me to this next phase of my career.”

A protein, measured conventionally, is treated as a single entity with a single concentration. But proteins do not exist as uniform molecules. They appear in multiple distinct forms – shaped by genetic variation, alternative splicing, post-translational modification, damage, and fragmentation – and those forms, known as proteoforms, often differ significantly in their biological behaviour, their relevance as biomarkers, and their susceptibility to therapeutic targeting.

In cancer, for instance, associating a protein with a patient outcome without accounting for its proteoform variants gives an incomplete picture – one that may miss the very molecular dynamics that determine how a tumour behaves or how a patient responds to treatment. The potential for proteoform-level analysis to deepen biological understanding is considerable; the techniques to realise that potential are still maturing, which means the territory ahead remains largely open.

Working with the Kelleher group, Aniel has recently completed a manuscript in JASMS describing a simple and highly reproducible method capable of resolving thousands of proteoforms from plasma, notable above all for its accessibility, and for what that accessibility could mean for researchers and clinicians who have lacked the infrastructure to engage with this level of biological detail. Developing the method, the team aimed to maximise proteoform coverage and quantitative reliability in plasma, which required reliable foundations at every analytical level, including the chromatographic level. The reproducibility and sensitivity of Aurora Series columns had already proven itself in the group’s bottom-up proteomics work. As Aniel puts it,

“Using these columns allowed us to benchmark proteoform quantification against peptide-level measurements and to challenge the traditional assumption of a single protein concentration model.”

An assumption that, once questioned, opens up a considerably richer picture of what plasma proteomics can reveal.

A vision grounded in reality

When asked what excites him most about proteomics right now, Aniel points to a broader shift in how the field is conceptualised: the integration with other omics disciplines, the movement toward population-scale studies, and a growing emphasis on standardised analytical controls. Together, he believes, these changes are making proteomics more robust, more comparable across research contexts, and more useful for both basic research and clinical medicine.

His most ambitious vision follows from everything he’s built and observed. Given the resources, the goal would be to enable “a deeper understanding of proteoform diversity and its direct relevance to human health and disease” – achieved through a large-scale proteoform analysis of plasma from thousands of individuals, supported by a dedicated biobank and a centralised research centre equipped with multiple cutting-edge mass spectrometry platforms, drawing on longitudinal samples from both healthy populations and those at risk of disease.

The obstacles are real. Countries like Austria possess superb biobanks but combining that material with state-of-the-art mass spectrometry remains administratively and logistically difficult due to permissions, paperwork, and the work of persuading institutions to open their collections to large-scale proteomics research. His experience at Lund, building infrastructure that linked rigorous sample handling with integrated multi-omics pipelines, showed him both what was possible and how far the field still has to go.

Part of what makes the vision necessary, in his view, is the question of what “healthy” actually means. Health is relative; one person healthier than another in measurable ways, but studies of physically active people in their seventies have shown that subjective feelings of poor health can coexist with objectively strong physiological markers; the relationship between molecular data and lived experience is complex and shaped by many factors. A large, longitudinal, proteoform-level dataset from diverse populations may not resolve that complexity, but it would give researchers far better tools for navigating it. It’s a vision that could quietly enable a great deal of the science that matters most.

Aniel, the ‘proteomicist’

“Proteomics”, Aniel observes, “has continuously reinvented itself.”

So, in many ways, has he. It’s a big part of why he chooses to describe himself as a ‘proteomicist’. Proteomics, as he sees it, is more than a field or set of techniques. It’s a way of thinking: a discipline that demands speculation, hypothesis, and the willingness to prove what you believe to be true. Using the term ‘proteomicist’ reconnects him with that mindset: the reminder that you are speculating, so the burden of proof is on you – and you need to be adaptable. When a new instrument arrives, a field shifts, or a career takes an unexpected turn, a proteomicist doesn’t cling to familiar ground but renovates their thinking entirely.

Looking back on a career that has spanned continents, disciplines, and paradigm shifts in what proteomics can do, it’s hard to argue with the approach. The next reinvention, whatever form it takes, seems unlikely to find him unprepared.

Detailed Q&A