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Decoded: How Cancer Cells Cripple Immune System

Anti-PD1 therapy blocks interaction between PD-1 -- a protein on the surface of T-cells -- and PD-L1, PD-1's counterpart molecule on tumour cells, thus reinvigorating T-cells and allowing them to unleash killing power on the tumour

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The research offers a paradigm-shifting picture of how cancers take a systemic approach to suppressing the immune system. Pixabay
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Researchers have found that cancer cells send out biological “drones” to fight the immune system and survive.

The study showed that cancer cells release “drones” — small vesicles called exosomes circulating in the blood and armed with proteins called PD-L1 that cause T-cells to tire before they have a chance to reach the tumour.

The research offers a paradigm-shifting picture of how cancers take a systemic approach to suppressing the immune system.

In addition, it also points to a new way to predict which cancer patients will respond to anti-PD1 therapy that disrupts immune suppression to fight tumours.

“Immunotherapies are life-saving for many patients with metastatic melanoma, but about 70 per cent of these patients don’t respond,” said Guo Wei, Professor at the University of Pennsylvania.

“These treatments are costly and have toxic side effects so it would be very helpful to know which patients are going to respond,” Wei added.

Cancer
Representational image. Pixabay

Anti-PD1 therapy blocks interaction between PD-1 — a protein on the surface of T-cells — and PD-L1, PD-1’s counterpart molecule on tumour cells, thus reinvigorating T-cells and allowing them to unleash killing power on the tumour.

In the study, published in the journal Nature, the team found that exosomes from human melanoma cells also carried PD-L1 on their surface. Exosomal PD-L1 can directly bind to and inhibit T-cell functions.

Identification of the exosomal PD-L1 secreted by tumour cells provides a major update to the immune checkpoint mechanism, and offers novel insight into tumour immune evasion.

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According to the researchers, exosomes are tiny lipid-encapsulated vesicles with a diameter less than 1/100 of a red blood cell.

Since a single tumour cell is able to secrete many copies of exosomes, the interaction between the PD-L1 exosomes and T-cells provides a systemic and highly effective means to suppress anti-tumour immunity in the whole body. This may explain why cancer patients might have weakened immune system, they noted. (IANS)

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New Drug to Give Hopes to Bone Marrow Cancer Patients

It reduced the risk of progression or death by more than 50 per cent in both groups

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Cancer
Cancer Ribbon. Pixabay

A therapeutic drug has been found to improve outcomes and survival rates for patients with a serious type of bone marrow cancer.

In a clinical trial by researchers at Newcastle University in Britain, patients with newly diagnosed myeloma were treated with a drug called lenalidomide.

The results, published in the journal The Lancet Oncology, showed an improvement for those who received lenalidomide drug, compared to those not receiving it.

“This is a major breakthrough as it shows that the long-term use of lenalidomide significantly improves the time myeloma patients stay in remission after initial therapy,” said Professor Graham Jackson from the Northern Institute for Cancer Research at Newcastle.

Myeloma is a cancer of the plasma cells and it can affect several areas of the body, such as the spine, skull, pelvis and ribs. Current treatment usually involves chemotherapy and a stem-cell transplant.

cancer
New drug offers hope for bone marrow cancer patients. Pixabay

“It is a huge step and, importantly, identifies that for younger patients lenalidomide improves their overall survival for this difficult-to-treat bone marrow cancer,” Jackson said.

“Our research highlights that lenalidomide should be considered for newly diagnosed patients following stem-cell transplantation,” he added.

As part of the study, a total of 1,137 newly diagnosed patients were randomly assigned to lenalidomide maintenance therapy and 834 patients to observation – this was after they completed their initial treatment.

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The results show that lenalidomide can prolong the average remission time by more than two years in younger patients and by well over a year in older, less fit patients.

It reduced the risk of progression or death by more than 50 per cent in both groups. (IANS)