Tag: cancer

Categories : CancerTags :

Elevated Cancer Risk in 9/11 Responders 20 Years On

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Image by David Mark from Pixabay

Associations between responders exposed to toxins at the World Trade Center (WTC) collapse site and increased cancer risk continue to be observed 20 years after the tragic event.

Thousands of rescue workers and first responders were exposed to toxins (asbestos, polychlorinated biphenyls, benzene, dioxins) in the aftermath of the World Trade Center attacks on September 11, 2011. Two studies recently published in Occupational & Environmental Medicine reported on the cancer incidence rates among the WTC Health Program General Responder Cohort.

According to the first study, male New York City firefighters exposed to the WTC site had higher rates of all cancers 13% increase and a younger median age at diagnosis (55.6 vs 59.4 years) compared with male non-WTC-exposed firefighters.

The WTC-exposed firefighters had increased rates of a number of cancers, the highest of which was thyroid cancer (153%) reported Mayris Webber, DrPH, of the Bureau of Health Services at the Fire Department of the City of New York, and colleagues.

The second study from Charles Hall, PhD, of Albert Einstein College of Medicine in the Bronx, and colleagues, found that, beginning in 2007, rescue/recovery workers at the WTC site had a 24% increased risk for prostate cancer compared with the general population in New York State.

Webber and colleagues noted that all firefighters are repeatedly exposed to occupational hazards, including known carcinogens. Their 2016 study found no difference between WTC-exposed firefighters and a group of non-WTC-exposed firefighters from three other cities. The current study extended follow-up to allow for detection of cancers up to 15 years after WTC site exposure.

In this analysis of 10 786 WTC-exposed firefighters and 8813 non-WTC-exposed firefighters, prostate cancer was the most commonly diagnosed cancer among both groups.

In comparison to the US male population, all-cancer incidence among exposed firefighters was “higher than expected”, an increase of 9% even after adjustment for possible surveillance bias.

The researchers adjusted for earlier detection made possible through free screenings, but elevated rates persisted for all cancers (7%), prostate cancer (28%), non-Hodgkin lymphoma (21%), and thyroid cancer (111%).

Webber and colleagues acknowledged that assessment of cancer risk among WTC-exposed firefighters is complex, as “these firefighters were subject to carcinogenic exposures, while also enduring enormous physical and mental burdens related to the attacks.”

“Evidence is slowly accruing about cancer and other long latency illnesses in relation to WTC exposure, although much remains to be determined,” they added.

Research has shown a lag of 10 to 20 years from exposure to a carcinogen to prostate cancer diagnosis. While WTC exposure was known to be linked to prostate cancer risk among responders, the length of time between exposure and cancer diagnosis was unknown.

Among the 54 394 rescue/recovery workers in the study, 1120 prostate cancer cases were diagnosed from 2002 to 2015.

The median time from the attacks to a diagnosis was 9.4 years, with the majority (66%) of cases diagnosed from 2009 to 2015.

Higher screening rates among first responders may have contributed to the increased incidence of prostate cancer seen in the study, the researchers acknowledged.

Comparing the responders who arrived earliest to the site with those who arrived later revealed a positive, monotonic, dose-response association with the early (2002-2006) and late (2007-2015) periods.

“The increased hazard among those who responded to the disaster earliest or were caught in the dust cloud suggests that a high intensity of exposure may have played some role in premature oncogenesis,” Hall and colleagues wrote. “Our findings support the need for continued research evaluating the burden of prostate cancer in WTC responders.”

Source: MedPage Today

Categories : Cancer PaediatricsTags :

Existing Drug Could Target Childhood Leukaemia

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Existing Drug Could Target Childhood Leukaemia

A new study published in PNAS has shown that the tumour-inhibiting gene TET2 is silenced in a large fraction of cases of acute lymphoblastic leukaemia (ALL) in children. The scientists show that the gene can be reactivated by an existing drug, 5-azacytidine, suggesting that it could be used a as targeted therapy for ALL in children.

“T-cell acute lymphoblastic leukaemia (T-ALL) is a devastating disease for the affected children and their families. One of five children affected do not survive the disease. The ultimate goal of my research is to ensure that all children can be cured. Our discovery may pave the way for clinical studies of 5-azacytidine as a new therapy for this poorly understood disease. The more treatment options we have for T-ALL the more chance we have of beating this aggressive cancer,” explained study leader Colm Nestor, senior lecturer in the Department of Biomedical and Clinical Sciences .

One of the characteristics of cancer cells is that they lose their cellular identity. One of the reasons for this is certain genes being silenced while others are activated. Switching genes on and off is controlled by epigenetic modification, where small chemical groups are attached to and removed from DNA, such as DNA methylation. The pattern of DNA-methylation is often altered in cancer cells, making them attractive targets for cancer drug research.

In the recently published study, the researchers were interested in an enzyme, TET2, that removes methyl groups from DNA. The gene that codes for TET2 is often affected by mutations in adult leukaemias. In children however, harmful mutations in TET2 are very rare, which led the researchers to speculate whether TET2 function is affected differently in child leukaemias. They analysed the gene expression patterns in cancer cells from more than 300 patients with T-ALL, and found that in many cases the TET2 gene was silenced.

It turned out that  methylation often silenced the TET2 gene. The scientists therefore decided to treat tumour cells in culture with a drug, 5-azacytidine, that removes methyl groups from DNA. This drug is used to treat certain leukaemias in adults.

“We found that one type of T-ALL cell, whose DNA seems to be highly methylated, is more sensitive to azacytidine than other cells that are not highly methylated. The drug actually turns silenced TET2 back on by demethylating it, so this might be a targeted therapy for a subset of cases. We suggest that azacytidine may have a doubled effect in these cells, since both the drug itself and TET2 kill cancer cells by demethylating the genome,” explained Colm Nestor.

Since 5-azacytidine is an approved drug, the researchers hope that it will be a much quicker path to treatment than when developing a novel drug.

“Chemotherapy agents have a broad effect and can be used for many patients, but they also kill healthy cells and can give rise to serious undesired effects. Targeted treatment, on the other hand, only works for a small fraction of patients, but is extremely specific. We need an arsenal of drugs to use for patients who experience relapses, and for those whose cancer does not respond to chemotherapy,” said Colm Nestor.

The researchers will continue with experiments to determine the effects of activating TET2 in these cancer cells, and to see if 5-azacytidine can function as targeted therapy in other types of cancer.

“The fact that we can target the loss of TET2 using the drug 5-azacytidine makes me hopeful that this treatment can help T-ALL patients in the future,” said researcher Maike Bensberg, PhD student at Linköping University.

Source: Linköping University

Categories : Cancer PaediatricsTags :

A Brief Window of Opportunity to Halt Certain Paediatric Gliomas

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Photo by Jeffrey Riley on Unsplash

In a pre-clinical study, investigators identified a vulnerability in a developmental signaling pathway that can be hijacked to drive paediatric low-grade glioma (pLGG) formation.

The study, published in Developmental Cell, demonstrated that targeted treatment prevents tumor formation, long before irreversible damage to the optic nerve can cause permanent loss of vision. This finding will inform chemo-prevention therapeutic trials in the future.

Brain tumours are the most common solid tumours in children, the most prevalent of which are pLGGs, of which 10 to 15% arise in patients with the familial cancer predisposition syndrome known as neurofibromatosis type 1 (NF1). Thi increases risks of developing tumours along the nerves and in the brain.

Almost 20% of children with NF1 develop pLGGs along the optic pathway, also known as NF1-associated optic pathway glioma (NF1-OPG). Despite many advances in cancer therapy, there are no definitive therapies available that prevent or alleviate the neurological deficits (i.e. vision loss) and that could improve the quality of life.

“The evidence presented can inform chemoprevention therapeutic trials for children with NF1-OPG. This therapeutic strategy may also be applicable to children with the developmental disorders that are at high risk of developing pediatric tumors, such as other RASopathies,” said Yuan Zhu, PhD, scientific director and Gilbert Family Endowed professor at the Gilbert Family Neurofibromatosis Institute and associate director of the Center for Cancer and Immunology Research.

The mechanism of vulnerability to pLGGs during development is not fully understood. It could be that the cell population of origin for this debilitating tumour is transiently proliferative during development. The NF1 gene produces a protein that inhibits MEK/ERK signalling, thereby helping regulate normal cell proliferation, survival and differentiation. With loss of NF1 function, it abnormally activates the MEK/ERK signalling pathway, leading to tumour formation.

Certain transient cells present during development of the brain and optic nerve are vulnerable to tumour formation because they depend on MEK/ERK signalling. Researchers identified cells dependent on the pathway and grew during a transient developmental window as the lineage-of-origin for NF1-OPG in the optic nerve. They then used a genetically engineered pre-clinical model to design a transient, low-dose chemo-preventative strategy, which prevented these tumours entirely.

“When we provided a dose-dependent inhibition of MEK/ERK signaling, it rescued the emergence and increase of brain lipid binding protein-expressing (BLBP+) migrating GPs glial progenitors, preventing NF1-OPG formation,” the researchers wrote. “Equally importantly, the degree of ERK inhibition required for preventing NF1-OPG formation also greatly improved the health and survival of the NF1-deficient model.”

Clinical trials using MEK inhibitors (MEKi) are underway for children as young as 1 month old, making the design of a chemo-preventative trial using a MEKi to treat children with NF1 more feasible. This treatment approach might not only prevent OPG formation, but also other NF1-associated and RASopathies-associated developmental defects and tumours.

Source: Children’s National Hospital

Categories : Cancer HospitalsTags :

Cancer Surgery Patients Have a Reduced Hospital Stay with ‘Prehabilitation’

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Photo by Martha Dominguez de Gouveia on Unsplash


A new approach to improve their fitness for surgery reduced the length of hospital stay for cancer patients, according to a new study.

Termed ‘prehabilitation’, the study’s approach includes exercise, nutrition and psychological and social interventions to bolster physical and mental health before surgery.

The study, published in the Annals of Surgery, found that prehabilitation interventions of between one and four weeks reduced cancer patients’ stay in hospital by 1.8 days compared with usual care.

Study author Dr Chris Gaffney from Lancaster Medical School said: “Surgery is like a marathon in terms of stressing the body, and you wouldn’t run a marathon without training.”

The researchers found that as little as one week can still benefit patient outcomes, indicating that prehabilitation should be recommended to accelerate recovery from cancer surgery, as shown by a reduced hospital length of stay.

Study author Dr Joel Lambert, now a postgraduate student at Lancaster Medical School and a surgeon at East Lancashire Teaching Hospitals NHS Trust, said: “We think that it may also confer a survival advantage for cancer patients as they can get to follow up treatments like chemotherapy more quickly.

“We think that the patient groups most likely to benefit are the ones with lower levels of fitness at baseline. In the Northwest we have some of the most socioeconomically deprived populations in the UK. This subset tend to have more co-morbid conditions hence less fit.”  

The patients studied were those with liver, colorectal, and upper gastrointestinal cancer, and who are often less fit than other cancer patients.

The study interventions were grouped into three types

  • Multimodal prehabilitation: exercise, which included both nutrition and psychosocial support,
  • Bimodal prehabilitation: exercise and nutrition or psychosocial support
  • Unimodal prehabilitation: exercise or nutrition alone

The exercise interventions included aerobic, resistance, and both aerobic and resistance exercises at all levels of intensity, some supervised by a kinesiologist or physiotherapist, while others were home-based exercise regimes. These ranged from one to four weeks and all interventions were within the current NHS surgery targets for cancer surgery.

The researchers concluded: “Future studies should focus on identifying patients who would benefit most from prehabilitation and the mechanistic underpinning of any improvement in clinical outcomes. Studies should closely monitor nutrition intake to determine if the response to exercise prehabilitation is dependent upon nutritional status. Lastly, mortality should be monitored for 12 months post surgery to determine if prehabilitation has any effect beyond 30 or 90 days.”

Source: Lancaster University

Categories : Cancer Mental HealthTags :

How do Patients Who Exit Clinical Trials Early Feel?

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Source: JD Mason on Unsplash

A new study has helped researchers understand the experiences of people who withdraw from clinical cancer trials.

Cancer clinical trials (CCTs) provide patients with an opportunity to receive experimental drugs, tests, and/or procedures that may lead to remissions. Such opportunities can be a great benefit for those who took part, but there is little known of the experiences of participants who withdraw from CCTs.

To address this, a first-of-its-kind study from the University of Pennsylvania School of Nursing (Penn Nursing) was conducted to better understand the post-trial needs of these patients and define responsible transitions when patients exit CCTs.

“Understanding the post-trial needs of patients with cancer and their families represents a measure of ethical respect of the many contributions that patients with cancer make to advancing our scientific knowledge and finding treatments that save lives,” said the study’s lead researcher, Connie M Ulrich, the Lillian S Brunner Chair in Medical and Surgical Nursing, professor of nursing, professor of medical ethics and health policy.

The study revealed three important areas:

  • Patients exiting CCTs feel intense symptoms, emotions, and awareness that their life spans are short and options seem limited.
  • The limited discussions with patients who are exiting on their immediate post-trial care needs can result in many feeling that there is no clear path forward.
  • Good communication that deliberately includes attention to post-trial needs throughout the CCT is needed to help scared and disappointed patients navigate their next steps.

The study is set for publication on the JAMA Network.

Source: University of Pennsylvania

Categories : Diseases, Syndromes and ConditionsTags :

Host Genes Can Hinder H. Pylori Eradication

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Helicobacter pylori is a strong risk factor for gastric cancer and other gastrointestinal disorders, and efforts to eradicate it using a combination of antibiotics and proton pump inhibitors (PPIs) often fail.

A new study has linked this eradication failure with genetic variations that increase the activity of the CYP2C19 enzyme, which metabolises first-generation PPIs.

These so-called ‘fast metabolisers’ may prevent PPIs from suppressing gastric acid production, which is necessary for successful H. pylori eradication.

Analysing 57 studies from 11 countries, the researchers found that the failure rate of H. pylori eradication more than doubled in people with a version of the CYP2C19 gene that increased its metabolic activity. Their results were published in Gastroenterology.

However, CYP2C19 variants were not linked to eradication failure if the fast metabolisers were treated with newer PPIs such as esomeprazole and rabeprazole, which are less metabolised by the enzyme or which bypass CYP2C19 metabolism.

Further well-designed studies are needed to determine whether eradication rates could be improved with higher or more frequent dosages of first-generation PPIs to people with the fast metaboliser gene variant, noted the paper’s corresponding author, Shailja Shah, MD, MPH.
“Even small improvements in H. pylori eradication rates would likely translate to substantial collateral health, economic and societal benefits,” the researchers concluded.

Source: Vanderbilt University

Categories : Ageing CancerTags :

Cancer Survivors Experience Accelerated Ageing

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Source: JD Mason on Unsplash

A new study published in Journal of the American Geriatrics Society indicates that cancer survivors, especially older ones, are more likely to experience faster functional decline as they age, compared with those without a history of cancer.

For the study, 1728 men and women (aged 22 to 100 years) were evaluated from 2006 to 2019, with 359 of these adults reporting a history of cancer. Among all participants, a history of cancer was associated with a 1.42 greater odds of weak grip strength. Those with a history of cancer and over 65 had a 1.61 greater odds of slow gait speed than those with no cancer history, and also had lower physical performance scores. Additionally, compared with those with no history of cancer, older individuals with a history of cancer experienced steeper declines in grip strength and gait speed. Reduced prefrontal cortex area is one of the factors thought to contribute to slow gait.

“Findings from our study add to the evidence that cancer and its treatment may have adverse effects on aging-related processes, putting cancer survivors at risk for accelerated functional decline,” said senior author Lisa Gallicchio, PhD, of the National Cancer Institute. “Understanding which cancer survivors are at highest risk, and when the accelerated decline in physical functioning is most likely to begin, is important in developing interventions to prevent, mitigate, or reverse the adverse aging-related effects of cancer and its treatment.”

Source: EurekAlert!

Categories : Immune SystemTags :

Lipid Shield Protects Both Immune and Cancer Cells

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Colourised scanning electron microscope image of a natural killer cell. Credit: National Institutes of Health

A newly discovered lipid ‘shield’ that prevents natural killer cells from being destroyed by their own deadly biological weapons also allows some cancer cells to evade an immune system attack, a study at Columbia University has found.

The findings, which may lead to new treatments for aggressive cancers, were published in the journal PLoS Biology.

Natural killer cells are efficient assassins that can eliminate up to six infected or cancer cells each day. The deadly immune cells grab onto their target and blast it with toxic proteins and enzymes that punch holes in the cell’s membrane. But these substances are also capable of destroying the natural killer cell’s membrane during the attack.

But how do natural killer cells survive releasing this blast of deadly substances? “I’ve been working on natural killer cells since the early 1990s, and every time I gave a talk about these cells, someone always asked that question,” said study leader and immunology expert Jordan Orange, MD, PhD, a professor at Columbia University Vagelos College of Physicians and Surgeons. “And nobody really knew until now.”

Avoiding self-destruction

Yu Li, a graduate student working with Prof Orange to understand how natural killer cells work and co-author of the study, thought the answer might lie in the double layer of lipids that makes up the outer membranes of all cells. Compared with other cells, Li noticed, the membranes of natural killer cells looked more orderly and more densely packed with lipids when viewed under a microscope.

“There were a lot of hypotheses about why natural killer cells don’t kill themselves during their attack on other cells, but they all proposed there might be a magic, unknown protein protecting these cells,” Li says. But Li had doubts. “Based on biophysical considerations, I didn’t think a protein would be strong enough to protect the cells. When I looked at the cells, I thought of lipids.”

To test out his idea, he exposed the membranes to a compound that weakens the structure of the lipid layer. With less dense and less orderly membranes, the natural killer cells were unprotected from their own toxic blast—and perished along with their targets.

Shields up

To survive their own toxic blast natural killer cells reinforce their membranes immediately beforehand, Li found. The small granules holding the deadly substances move to the outer edge of the natural killer cell. As the granule unleashes its cargo into the space between the killer and target cells, its own unusually dense lipid membrane merges with and reinforces the natural killer cell membrane.

“In essence, Li found that the membrane turns into a blast shield,” Prof Orange says. “And the protection comes from the way the membrane’s lipids are arranged. When the lipids are arranged in a more orderly fashion, more lipids can be packed into the membrane. The toxic substances simply can’t find a way into the membrane,” Orange says.

Cancer cells steal the idea

Besides natural killer cells, some cancer cells have adopted this defence against natural killer cells’ attacks, Li and Prof Orange found. They may also use this as a defence from cytotoxic T cells, another immune cell that uses lipids for self-protection.

Li found that cells from an aggressive breast cancer known to be impervious to natural killer cells fortify their membranes during the attack. The reinforcement was vital for the cancer cells, Li discovered, because when he added a membrane compound that disrupts lipid packing, the cancer cells were rendered vulnerable.

“We don’t know yet if this is a general mechanism by which cancer cells resist natural killer cells,” Li said. “If it is generalisable, we can start to think of therapies that disrupt the tumor cell membrane and make it more susceptible to attack by the immune system.” 

Source: Medical Xpress

Categories : CancerTags :

Sunlight-fuelled Chemical Changes Drive Melanomas

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Photo by Amy Humphries on Unsplash

Mutations in DNA that lead to melanoma result from a sunlight-fuelled chemical conversion in DNA, not just a DNA copying error as previously believed, according to a new study.

The findings of the study, led by the Van Andel Institute scientists and published in Science Advances, upend long-held beliefs about the mechanisms underlying the disease, reinforce the importance of prevention efforts and offer a path forward for investigating the origins of other cancer types.

“Cancers result from DNA mutations that allow defective cells to survive and invade other tissues,” said corresponding author Gerd Pfeifer, PhD, a VAI professor. “However, in most cases, the source of these mutations is not clear, which complicates development of therapies and prevention methods. In melanoma, we’ve now shown that damage from sunlight primes the DNA by creating ‘premutations’ that then give way to full mutations during DNA replication.”

Melanoma begins in pigment-producing skin cells. Although less common than other types of skin cancer, melanoma is more likely to metastasise, significantly reducing patient survival. Previous studies have shown that melanoma has the most DNA mutations of any cancer. Like other skin cancers, melanoma is linked to sun exposure, specifically UVB radiation which damages cells and DNA.

Most cancers are to arise when damaged DNA causes a mutation that is propagated through subsequent cellular generations. In the case of melanoma, however, Pfeifer and his team found a different mechanism that produces disease-causing mutations – the introduction of a chemical base not normally found in DNA that makes it prone to mutation.

In melanoma, the problem occurs when UVB radiation from the sun hits certain sequences of bases: CC, TT, TC and CT, causing them to chemically link together and become unstable. This resulting instability induces a chemical change to cytosine that transforms it into uracil, a chemical base found in the messenger molecule RNA but not in DNA. This change, called a “premutation,” primes the DNA for mutation during normal cell replication and eventually melanoma.

These mutations may lay dormant for years, not causing disease. More mutations can build up throughout a person’s lifetime exposure to sunlight, resulting in a stubborn cancer that evades many therapeutic options.

“Safe sun practices are very important. In our study, 10–15 minutes of exposure to UVB light was equivalent to what a person would experience at high noon, and was sufficient to cause premutations,” Prof Pfeifer said. “While our cells have built-in safeguards to repair DNA damage, this process occasionally lets something slip by. Protecting the skin is generally the best bet when it comes to melanoma prevention.”

The study used a method developed by Prof Pfeifer’s lab called Circle Damage Sequencing, enabling scientists to ‘break’ DNA at each point where damage occurs. DNA is coaxed into circles and replicated with PCR. With enough DNA, next-generation sequencing then identifies which DNA bases are present at the breaks. Pfeifer and colleagues plan to use this technique going forward to examine other types of DNA damage in different kinds of cancer.

Source: Van Andel Institute (VAI)

Journal reference: Jin, S-G., et al. (2021) The major mechanism of melanoma mutations is based on deamination of cytosine in pyrimidine dimers as determined by circle damage sequencing. Science Advances. doi.org/10.1126/sciadv.abi6508.

Categories : Cancer Immune SystemTags :

Unleashing the Immune System to Attack Cancers

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Shown here is a pseudo-colored scanning electron micrograph of an oral squamous cancer cell (white) being attacked by two cytotoxic T cells (red), part of a natural immune response. Photo by National Cancer Institute on Unsplash

A potential treatment has been identified, that could boost the immune system’s ability to find and destroy cancer cells, by impeding certain cells which regulate the immune system, which in turn can unleash other immune cells to attack tumours in cancer patients.

“A patient’s immune system is more than able to detect and remove cancer cells and immunotherapy has recently emerged as a novel therapy for many different types of cancers,” explained study leader Nullin Divecha, Professor of Cell Signalling at the University of Southampton. “However, cancer cells can generate a microenvironment within the tumour that stops the immune system from working thereby limiting the general use and success of immunotherapy,” he continued.

One of a number of types of T cells, Teffector cells (Teffs) carry out the task of detection and removal of cancer cells . How well Teff cells work in detecting and removing cancer cells is partly governed by other T cells called T-regulatory cells, or Tregs for short. Tregs physically interact with the Teff cells, producing molecules which dampen the functioning of the Teff cells.

Prof Divecha added, “Tregs carry out an important function in the human body because without them, the immune system can run out of control and attack normal cells of the body. However, in cancer patients we need to give the Teff cells more freedom to carry out their job.”

Molecules released by tumour cells exacerbate the problem by attracting and gathering Tregs, reducing the activity and function of Teff cells even further. Though there are mechanisms to inhibit Treg cells, since Treg and Teff cells are very similar, Teff cells are also generally inhibited.

In this new study, published in PNAS, scientists from the University of Southampton and the National Institute of Molecular Genetics in Milan showed that inhibition of a family of enzymes in cells called PIP4K could be the answer to how to restrict Tregs without affecting Teffs.

The research team isolated Tregs from healthy donors and used genetic technology to suppress the production of the PIP4K proteins. They saw that loss of PIP4Ks from Treg cells stopped their growth and response to immune signals, in turn stopping them from impeding Teff cell growth and function.

Importantly, the loss of the same enzymes in Teff cells did not limit their activity.

“This was surprising because PIP4Ks are in both types of T cells in similar concentrations but our study shows that they seem to have a more important function for Tregs than Teffectors,” said Dr. Alessandro Poli who carried out the experimental research.

Scientists must next develop molecules in order to inhibition of PIP4K as a potential therapy for patients. “Towards this end we show that treatment with a drug like inhibitor of PIP4K could enable the immune system to function more strongly and be better equipped to destroy tumour cells.”

Source: EurekAlert!