Researchers at the Medical Research Council in Cambridge have found markers for cancer cells that may help detect thousands of new cases of cancer a year. The markers are already part of an MRC-developed device that screens for cancer of the oesophagus, are being trialled for cervical cancer screening and could potentially be used in a test for bowel cancer. Researchers at the MRC Cancer Cell Unit in Cambridge have been identifying the genes and proteins that cause cancer cells to be different from non-cancer cells, which could be used as distinguishing markers. In the 1990s, Professor Ron Laskey at the unit identified certain proteins that are needed in order for DNA to be copied, during what is known as the ‘cell cycle’. Cancer cells remain in the cell cycle when they shouldn’t be, therefore proteins involved in the replication process would serve to identify these cells. Along with other teams around the world, Professor Laskey’s group found specific proteins, called minichromosome maintenance proteins (MCMs), which are abundant in cells from cancers and absent from almost all normal cells1. Other less-effective markers were also found, but the MCM proteins are superior because they are present throughout the cell cycle and are more abundant, stable and distinguishable.

Scientists continue to study tumor markers and their possible role in the early detection and diagnosis of cancer. The NCI is currently conducting the Prostate, Lung, Colorectal, and Ovarian Cancer screening trial, or PLCO trial, to determine if certain screening tests reduce the number of deaths from these cancers. Along with other screening tools, PLCO researchers are studying the use of PSA to screen for prostate cancer and CA 125 to screen for ovarian cancer. Final results from this study are expected in several years. Cancer researchers are turning to proteomics (the study of protein shape, function, and patterns of expression) in hopes of developing better cancer screening and treatment options. Proteomics technology is being used to search for proteins that may serve as markers of disease in its early stages, or predict the effectiveness of treatment or the chance of the disease returning after treatment has ended.
Scientists are also evaluating patterns of gene expression (the step required to translate what is in the genes to proteins) for their ability to predict a patient’s prognosis (likely outcome or course of disease) or response to therapy.
NCI’s Early Detection Research Network is developing a number of genomic- and proteomic-based biomarkers, some of which are being validated. More information about this program can be found at http://edrn.nci.nih.gov/ on the Internet.