Removing Cancer’s Cloak of Invisibility

Copyright Promega.
Copyright Promega.
For decades scientists have been trying to harness the power of our immune system to fight cancer cells. It is not impossible to imagine that our immune system, which is sophisticated enough to fight against a multitude of invaders that threaten our health, should be able to tackle a deadly disease such as cancer. This formed the basis of testing a new type of cancer treatment known as immunotherapy. Immunotherapy for cancer means developing treatments to harness your immune system and using your own immune system to fight the cancerous cells.

But in reality it was hard to make this work. Because, as scientists discovered recently, cancer outsmarts the immune system by wearing a kind of “invisibility cloak”. Cancer is able to fool the immune system from recognizing that it is the enemy and in effect keeps the immune system from destroying it.

In a breakthrough discovery scientists have found a way around this treachery.

The breakthrough is in therapies called ‘checkpoint inhibitors’. Checkpoint inhibitors block the mechanisms that allow some tumor cells to evade the immune system. The drugs ensure that cancer cells are no longer be shielded from the immune system defenses, but are instead recognized as “foreign”. Continue reading “Removing Cancer’s Cloak of Invisibility”

Immune Checkpoint Inhibitors: Has Cancer Met its Match?

The cover of S. Mukerjee's book, The Emporer of All Maladies: The Biology of Cancer. Used courtesy of Wikimedia and WLU.
The cover of S. Mukerjee’s book, The Emporer of All Maladies: The Biology of Cancer. Used courtesy of Wikimedia and WLU.

Dr. Drew M. Pardoll, Johns Hopkins University School of Medicine in Baltimore, in his 2012 review, “The blockade of immune checkpoints in cancer immunotherapy” published in Nature Reviews Cancer (1) writes:

“The myriad of genetic and epigenetic alterations that are characteristic of all cancers provide a diverse set of antigens that the immune system can use to distinguish tumour cells from their normal counterparts.”

Tumors have antigens, so we should be able to address/attack these antigens with our immune system, right?

Various immune mediators as therapeutic agents against cancer have entered and mostly flopped in clinical trials over the past 30 or more years. As a graduate student in the 1980s I remember IL-2 and interferon raising many hopes. More recently, drugs against chronic myeloid leukemia and CLL have shown early promise. However, so far cancer cells have mostly won against these therapies. Yet recent news points to some exciting new therapeutic agents, that over the past 15 years or so, and in and out of clinical trials, are getting a leg up in the cancer battle. These drugs are immune checkpoint inhibitors. Continue reading “Immune Checkpoint Inhibitors: Has Cancer Met its Match?”