A University of Colorado Cancer Center study published in the journal PLoS ONE shows that bladder and lung cancers are marked by shared differences in the genetics that control the cell cycle. Measuring these genetic signatures could allow doctors to refine a patient’s prognosis, choose appropriate treatments, and perhaps offer new treatments that target shared genetic abnormalities.
Biomarkers allow researchers and doctors to diagnose, predict the course of, and, increasingly, treat cancers. But with about 40,000 genes in the human genome and far more steps between a gene and its expression as a protein, finding meaningful biomarkers is the proverbial search for a needle in a haystack. Traditionally, tissue samples from one cancer type are collected and then the genes in these samples are analyzed to see which, if any, are elevated, silenced or mutated. Unfortunately, despite the success of this approach in identifying candidate biomarkers, many biomarkers fail to stand up to further scrutiny; a gene that is elevated in a subset of 10 samples of, say, prostate cancer, may not be elevated in further cohorts of the same cancer.
The current study reasoned that biomarkers present in two or more related cancers would likely be more robust than single-cancer biomarkers. Previous studies link lung and bladder with tobacco use. So researchers gathered hundreds of samples of these cancers to search for common predictive markers. Could they pinpoint what in these tumors led to favorable or unfavorable outcomes?
First, researchers correlated gene expression to progression and survival, ending with a master list of all genes predictive of patient outcomes. Then they crossed these lists to look for commonalities between the cancers. They found clusters or “modules” of adjusted genes, all under the umbrella of the network that controls the cell cycle.