Master Switch May Help Cancer Cells Hide From Imm...( COLUMBUS Ohio -- A newly discovered ...)

COLUMBUS, Ohio -- A newly discovered gene mutation that works like a master switch may enable tumor cells to evade destruction by the immune system, new research shows.

The finding presents extraordinary possibilities for both cancer treatment and for organ transplantation. Turning the gene back on in cancer cells might one day allow physicians to make tumors more recognizable to the immune system -- and therefore more subject to destruction by the body.

Turning off the gene in tissue to be transplanted, on the other hand, might make the tissue less recognizable to the immune system and therefore less likely to be rejected by the body.

"It is very important to establish how human cancer evades being eliminated by the immune system," said Yang Liu, Kurtz Chair Professor of Pathology at Ohio State University's Comprehensive Cancer Center. "If we know how a tumor evades the immune system, we can study how to deal with it. This could lead to a way to increase the immune system's sensitivity to the tumor."

At the same time, said Pan Zheng, assistant professor of pathology and Liu's coworker, "in transplantation, we might use the switch to decrease the sensitivity of immune recognition and make the transplant more successful."

The discovery, published in the November 26 issue of the journal Nature, was made in tumors implanted into mice.

The study identified a master gene that controls the primary means by which cells alert the immune system of a problem -- that the cell is infected by a virus or that it has become cancerous, for example.

The system works by taking fragments of materials produced inside the cell and displaying those fragments on the outside of the cell. This work is done by major histocompatibility complex type I (MHC-I) molecules.

MHC-I molecules are produced deep inside the cell and, are then transported to the cell surface. During that journey, a piece of a different molecule from elsewhere in the cell
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Contact: Yang Liu
Liu-3@medctr.osu.edu
614-292-3054
Ohio State University
7-Jan-1999