Tag Archives: immunology

As we age, cancer rates go up as immune system winds down

Enlarge / T cells are central to the immune system’s response to cancer. (credit: NIAID)

The dominant idea about how cancer gets started is called the “two-hit hypothesis.” First proposed by Alfred Knudson in 1971, it holds that a cancer starts when one cell gets a mutation in both of its copies of a gene that normally blocks cancer formation (two hits). These two mutations disable the tumor-suppressing function in that cell, which then becomes cancerous. Eventually, the idea was expanded to include two hits not necessarily in the same gene but, rather, in genes controlling the same tumor-suppressing pathway.

But a new idea is challenging the two-hit hypothesis, shifting the focus to the role of the immune system in suppressing cancers. It’s an idea

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Our hearts beat with unexpected electrical help from immune cells

Enlarge (credit: Getty | UniversalImagesGroup)

Having a regular or irregular heartbeat may come down to moonlighting immune cells that surprisingly help power blood-pumping pulses, a new study in Cell suggests.

In a series of experiments, Harvard researchers caught immune cells hanging around and helping heart cells conduct electricity for their rhythmic beats. The immune cells, called macrophages, are best known for surveilling the body and devouring invading germs and debris. But in the heart, they snuggled up to heart cells and formed pores through which electrical current could pulse through the organ, allowing for synchronous heart muscle contractions that pumps blood.  The macrophages also helped neighboring heart cells recharge between pulses.

In genetically engineered mice, a lack of macrophages in the heart led to

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