Proteins from a newly discovered family of genes, LRIG, function as a retardant for a protein that is important to tumor cells. It is probably this mechanism that lends the gene family its inhibiting effect on cancer tumors.
This is shown in a dissertation by Jonas Nilsson at Umea University in Sweden, to be publicly defended on May 24.
Jonas Nilsson and his associates have identified a new family of genes, the leucin-rich and immunoglobulin-like (LRIG) family. They found that the first member of the family, LRIG1, shuts down the activity of the tumor protein ErbB1. LRIG1 introduces the ErbB1 protein to the protein degradation machinery, which in turn destroys the ErbB1 protein. In patients, they have also shown that expression of LRIG proteins is associated with increased survival rates in patients with malignant brain tumors.
Apace with the growth of our knowledge of oncology, new approaches have been developed for the treatment of tumors. For instance, treatments have been devised to seek out specific targets in the cancer cell, several of which are already in clinical use. One example is the treatment of breast cancer with Herceptin.
One type of target that these selective treatments seek out are receptors on the cell surface (receptors for growth factors). They are often hyperactive in tumors, which leads to increased resistance to chemo and radiation therapy, as well as increased tumor growth and metastasizing. Therefore, the idea is to shut down, or at least slow down, these hyperactive receptors as a way of defeating the tumor. The ErbB receptors belong to a class of cell-surface receptors, and when they are overly activated, which is often the case in tumors, they are associated with poor survival rates.