By Lina carolina 
A groundbreaking new study, leveraging a pioneering computational technique developed by researchers at University College London (UCL) and the Francis Crick Institute, has unveiled a critical link between the abundance of immune cells in a cancer patient’s blood and their survival rates. This innovative approach, detailed in the prestigious journal Nature Genetics, allows scientists to quantify specific types of immune cells – T cells and B cells – directly from whole genome sequencing (WGS) data for the first time, offering a powerful new lens through which to understand and combat cancer.
ImmuneLENS: A New Frontier in Cancer Genomics
The newly developed tool, christened Immune Lymphocyte Estimation from Nucleotide Sequencing (ImmuneLENS), represents a significant leap forward in our ability to decipher the complex interplay between the immune system and cancer. Traditionally, understanding the immune response in cancer has largely focused on analysing immune cells directly within the tumour microenvironment. However, ImmuneLENS shifts this paradigm by enabling researchers to assess the peripheral immune system, specifically the circulating immune cells in a patient’s blood, using the vast repository of whole genome sequencing data already being collected.
Whole genome sequencing involves a comprehensive analysis of an individual’s complete DNA, providing a blueprint of their genetic makeup. This intricate dataset holds invaluable information, including insights into the body’s immune cell composition, the presence of genetic mutations that drive cancer, and the body’s inherent capacity to fight disease. By unlocking these genetic instructions, scientists can glean deeper understanding of complex conditions like cancer.
Unlocking the 100,000 Genomes Project Data
The research team applied ImmuneLENS to an unprecedented scale, analysing over 90,000 whole genome sequencing samples from the landmark 100,000 Genomes Project. This ambitious initiative, spearheaded by Genomics England in collaboration with NHS England, has systematically collected and analysed the genomes of individuals with rare diseases and cancer, alongside a cohort of healthy participants. The sheer volume and richness of this data provided the ideal foundation for validating and demonstrating the power of ImmuneLENS.
Key Findings: Immune Cell Proportion as a Prognostic Indicator
The analysis revealed a striking disparity: cancer patients exhibited a significantly lower proportion of circulating T cells in their blood compared to their healthy counterparts. More importantly, this proportion of T cells emerged as a robust predictor of cancer prognosis. The study found that individuals with a higher percentage of T cells in their blood experienced a remarkable 47% reduction in deaths over a five-year period following surgery. This association remained statistically significant even after accounting for crucial confounding factors such as patient age, the stage of their cancer, and across all cancer types investigated.
Professor Nicholas McGranahan, a senior author of the study and a leading figure at the UCL Cancer Institute, underscored the transformative nature of these findings. "Most immune system analysis until now has focused on the tumour itself," Professor McGranahan stated. "So, the results we’re seeing using this new technique – which examines the number of immune cells in a person’s blood – are of considerable interest. What’s going on with immune cells in the blood seems to have a huge impact on cancer survival and may be able to predict how long a cancer patient will survive better than the number of T cells in the tumour alone."
He further elaborated on the potential of this discovery, noting, "There have been hints in previous research that this might be important, but being able to analyse immune system information at this scale is game-changing. The ability to compare immune cell changes in the blood and to what’s happening in the tumour environment opens up new avenues for cancer research, as well as healthcare research more widely."
Implications for Clinical Practice and Personalized Medicine
The implications of these findings for clinical practice are profound. The researchers suggest that these newly identified biological markers – specifically, the proportion of T cells in the blood – could be seamlessly integrated into existing genetic diagnostic tests. This would equip clinicians with a more comprehensive understanding of a patient’s immune status, thereby informing more precise and personalized treatment strategies.
"In terms of patient diagnosis and treatment, knowing whether a patient has relatively high or low numbers of immune cells in the blood, and how this corresponds to their prognosis, could help clinicians to decide on the best course of treatment for the individual," Professor McGranahan added.
The Complex Dance Between Cancer and the Immune System
Cancer, at its core, is a disease driven by genetic mutations within the body’s cells. While the immune system possesses the remarkable ability to detect and eliminate cells harbouring dangerous mutations, cancer has evolved sophisticated mechanisms to evade this immune surveillance and actively disrupt the immune response. Understanding this intricate battle requires a holistic approach, assessing both the local immune environment within and around the tumour, and the broader systemic immune response.
Large-scale genomic initiatives like the 100,000 Genomes Project have been instrumental in providing an unprecedented view of the genetic landscape of cancer. However, the precise quantification of immune cell populations within both the tumour and the wider immune system has remained a significant challenge until the advent of tools like ImmuneLENS.
Evolution of Immune Cell Analysis
ImmuneLENS builds upon earlier advancements, including a 2021 method that enabled the estimation of T cell proportions in whole exome sequencing data. However, ImmuneLENS extends this capability to whole genome sequencing and offers a more refined analysis of both T and B cells.
Age-Related Immune Decline and Cancer
The study also shed light on the impact of aging on the immune system in the context of cancer. It is well-established that the proportion of immune cells in the blood naturally declines with age in healthy individuals. However, the research found that this decline occurs at an accelerated rate in people with cancer. This phenomenon was observed to be more pronounced in male cancer patients compared to their female counterparts, although the underlying reasons for these sexual differences and their impact on overall survival remain an area for further investigation.
Early Warning Signs: B Cells and Pre-Cancerous Changes
Intriguingly, the researchers observed that individuals who appeared healthy at the time of their genome sequencing, but who subsequently developed cancer, often had lower-than-average levels of B cells in their blood. This finding suggests a potential link between reduced B cell counts and early-stage, or even pre-cancerous, changes in the immune system. These diminished B cell levels could represent an early indicator of disease or even a contributing factor to cancer development.
This discovery opens up exciting possibilities for the future of cancer early detection and for improving clinicians’ ability to predict a patient’s response to various treatments.
ImmuneLENS: A More Efficient "Haystack" Approach
Dr. Robert Bentham, the study’s first author from the UCL Cancer Institute, drew an analogy to explain the novel approach of ImmuneLENS: "Lots of approaches that measure immune cells from genetic data are like looking for a needle in a haystack. Our approach in this study instead looks at the haystack itself and asks how the presence of immune cells changes its overall shape. It’s a different, more efficient way of finding the needle."
He emphasized the broader utility of this method, stating, "One of the things this will allow us to do is to build significant immune datasets using data we already have from the many large-scale WGS cohorts but haven’t been able to interrogate until now. It will allow researchers to explore what’s happening in the immune system during health and disease, not just in cancer but potentially in many areas of medicine."
Delving Deeper into B Cell Diversity
Beyond quantifying T cells, ImmuneLENS also offers the advantage of distinguishing between different types of B cells. B cells play a crucial role in the adaptive immune response by producing antibodies, which are proteins designed to neutralize harmful agents such as viruses, bacteria, and mutated cells. As B cells mature, they specialize to produce specific types of antibodies. The research team leveraged this specialization process to accurately identify and classify B cells.
When applied to WGS data, this detailed analysis revealed that B cells producing IgM/D antibodies – a hallmark of the body’s initial encounter with a foreign antigen – were uniquely associated with improved survival outcomes in cancer patients. This suggests that these specific B cells may play a pivotal role in mounting an anti-tumour immune response. Their presence could also serve as a novel biological marker for cancer diagnosis, positioning them as a promising target for future research and therapeutic development.
Towards Clinical Implementation and Cost-Effectiveness
The next crucial step for the research team is to translate these findings into tangible clinical benefits. They propose that the newly identified biological markers, such as the proportion of T and specific B cells in the blood, can be integrated into the current battery of diagnostic tests for cancer patients at no additional cost. Professor McGranahan and his team have already secured funding from Cancer Research UK (CRUK) for a Biomarker Project Award, which will facilitate further work towards clinical implementation.
This integration could be particularly transformative for predicting a patient’s response to immunotherapy. While the proportion of T cells within a tumour is a recognized biomarker, it cannot currently be reliably measured using standard genomic tests. ImmuneLENS offers a viable solution, bridging this critical gap.
Expert Reactions and Future Directions
Dr. Nisharnthi Duggan, Research Information Manager at Cancer Research UK, expressed enthusiasm for the research: "Cancer Research UK is pleased to support this ongoing work investigating whether measuring immune cell levels in our blood can help predict cancer survival. We’re living in a golden age of research where we can use patient data in sophisticated ways to help us better understand cancer and how to beat it."
She added, "Further research is needed, but this could one day become a tool to help doctors personalize treatment for people with cancer."
The research is an integral part of the Cancer Research UK-funded TRACERx project, a large-scale study investigating the genetic basis of cancer and the immune response. Furthermore, the groundbreaking work was made possible through access to the invaluable data generated by the 100,000 Genomes Project, managed by Genomics England.
The development and validation of ImmuneLENS mark a significant milestone in cancer research, offering a powerful, cost-effective, and scalable method to unlock critical information about the immune system’s role in cancer. This advancement promises to not only enhance our understanding of cancer biology but also pave the way for more accurate prognostication, earlier detection, and ultimately, more personalized and effective treatments for patients worldwide. The potential for this technology to impact other areas of medicine, beyond oncology, also represents an exciting prospect for future scientific exploration.