Two recent investigations conducted by Oxford Population Health at the University of Oxford in the United Kingdom have explored links between thousands of blood plasma proteins and a range of cancers.
The initial study, published in Nature Communications on May 15, identified 371 plasma protein markers indicative of cancer risk. Notably, 107 of these markers were linked to cancers that were formally diagnosed up to 7 years later, hinting at a potential window for early detection and intervention.
The second study, released in Nature Communications on April 29, revealed correlations between 40 plasma proteins and several commonly encountered cancers.
The authors are optimistic that these findings could pave the way for early detection and treatment of cancers in their nascent stages, and possibly even prevent their onset altogether.
Can Professionals Detect Cancer Early?
The first study targeted statistical correlations between 1,463 plasma proteins and 19 cancer types in 503,317 adults aged 39 to 73, utilizing data from the U.K. Biobank. The second study focused on associations between 2,047 proteins and nine cancer types in 300,000 individuals from the same biobank.
Researchers also investigated potential explanations for why certain proteins were not linked to cancer.
These investigations employed proteomics, a field dedicated to studying proteins throughout the body, particularly in blood plasma. Proteomics integrates physical and biochemical methods with disciplines like computer science, genetics, and bioinformatics.
Proteins are pervasive in the body, present in blood serum, muscles, skin, bones, hair, urine, and various other tissues, with each person carrying a minimum of 10,000 different proteins.
While this study marks a preliminary advancement in understanding the interplay between plasma proteins and cancer, definitively pinpointing specific protein levels indicative of cancer falls beyond the purview of current research.
Potential Connections Between Plasma Proteins and Cancer Risk
In the initial study, potential associations were uncovered between plasma proteins and heightened risks of liver cancer, cancers affecting the digestive and gastrointestinal tracts, non-Hodgkin lymphoma, as well as colorectal, lung, kidney, brain, stomach, esophagus, endometrium, and blood cancers.
The subsequent investigation revealed correlations with triple-negative breast cancer, bladder cancer, lung cancer, and pancreatic cancer.
Joshua Atkins, PhD, BBmedSci, a senior genomic epidemiologist at the University of Oxford and one of the co-authors of both studies, highlighted the significance of these findings. “Some of the other links are quite interesting, too,” he commented. “Proteins that are not causal for cancer development but are a consequence of cancer growth can provide avenues for detecting cancers at an earlier stage when treatment can be more successful.”
The Clinical Significance of this Research
Richard Reitherman, MD, the medical director of Breast Imaging at the MemorialCare Breast Center at Orange Coast Medical Center, CA, who was not affiliated with the studies, elaborated to Medical News Today:
“These publications illustrate the correlation — not causation or presence — of specific proteins and their association with established common cancers. This foundational research is intended to deepen our understanding of how particular proteins are linked to human cancers.”
Nonetheless, “[d]isruption of these mechanisms can lead to diseases,” Atkins remarked, “including cancer. Certain proteins may pose higher cancer risks with elevated blood levels, while others may confer protection, where higher levels correspond to reduced risk.”
Atkins also acknowledged that his team is currently striving to determine the threshold levels of concern for these proteins, a process that may require considerable time.
David S. B. Hoon, PhD, a professor and director of the Genomic Sequencing Center at St. John’s Cancer Institute, CA — also not involved in the research — highlighted the extensive process involved in establishing healthy lipoprotein cholesterol levels. He stated, by way of example, that it took “thousands and thousands of tests, encompassing males and females, before clinical chemistry established cutoffs delineating what is genuinely positive, what is hazardous, and what constitutes the norm.”
Hoon also expressed concern that the research might not encompass adults of all age groups. “In the paper,” he remarked, “most of these patients are in their sixth or seventh decade. Consequently, many proteins identified as high-risk for cancers are merely age-related occurrences.”
Is Concern Warranted Regarding the Presence of These Proteins?
“These are proteins inherent in all of us,” noted Atkins.
Reitherman elucidated, “[o]ur blood system functions as the indispensable intermediary, akin to a complex subway network connecting all bodily organs and functions.”
“Similar to passengers in a subway system — such as proteins, carbohydrates, lipids, DNA, RNA, intact cells and sub-cellular particles, oxygen, carbon dioxide, minerals — various components enter the bloodstream,” Reitherman continued. “They’re transported to different body locations to partake in a myriad of intricate metabolic, respiratory, and cellular growth regulation processes or to be eliminated.”
He cited insulin as an example, explaining how it’s secreted by the pancreas into the bloodstream and subsequently “penetrates all bodily tissues, regulating numerous cellular functions, including blood glucose levels.”
Atkins cautioned against aggressively manipulating the levels of concerning proteins, stressing that proteins play pivotal roles in many vital bodily processes. Disrupting protein levels or function may yield adverse effects, he warned.
He highlighted the protein FGFR3, associated with heightened bladder cancer risk, but lowering its levels is linked to increased osteoarthritis risk.