Scientists have identified an enzyme that is absent in healthy colon tissue but abundant in colon cancer cells. The enzyme appears to drive the conversion of normal colon tissue into cancer by attaching sugar molecules, or glycans, to certain proteins in the cell. "Our data suggest (that) this specific enzyme seems to
affect a subset of proteins that could be involved in cell-cell adhesion," said Hans Wandall, from the University of Copenhagen in Denmark.

In other words, the glycan modifications changed the patterns in which cells stuck together, leading the cells to develop as something that looked more like a tumour than a healthy tissue. Understanding the role that sugar-modified (glycosylated) proteins play in healthy and cancerous cells is an emerging area of cancer biology that may lead to new therapies.

For the study published in the Journal of Biological Chemistry, the researchers examined a group of 20 enzymes that initiate the first step in a particular kind of glycan modification, called GalNAc-type O-glycosylation, found on diverse proteins. These enzymes, called GalNAc transferases (GalNAc -Ts) are variously found in different amounts in different tissues, but their functions are poorly understood.

The researchers found that one of the GalNAc-Ts, called GalNAc-T6, was absent in healthy colon tissue but abundant in colon cancer cells.