The University of Texas MD Anderson Cancer Center has recently found that healthy tissue may provide tell-tale signs that an individual may eventually develop lung cancer. In the Journal of the National Cancer Institute, lead author Humam Kadara, Ph.D., an assistant professor in Translational Molecular Pathology, published a study that has “double whammy applications.” His study found not only genes in tumors that distinguish cancer from healthy, but also genes that are expressed by cells neighboring tumors that vary in expression based on distance from the tumor.
Kadara and the rest of the research team looked at the entire transcriptome expression profiles of tumors, tissue of varying distance from tumors, and uninvolved tissue from the lungs of 20 patients with early-stage (I-IIIA) non-small cell lung cancer (NSCLC). They found 1661 genes differentially expressed between NSCLC and normal tissue. One of these genes, LAPTM4B, can lead to chemotherapy resistance if overexpressed by cells. “This is the first time the role of [LAPTM4B] in lung cancer has been studied,” Kadara said. “It was highly over-expressed in adjacent normal cells, indicating the possibility of future detection and treatment strategies.” This finding alludes to the second interesting point of the study: 422 genes were progressively differentially expressed by lung tissue of varying distance from tumors, with more intense expression occurring closest to the tumor. “These cancer-associated changes… may help us diagnose lung cancer earlier and develop more effective strategies for treatment,” added Kadara.
Other cancers, including gastric, esophageal, hepatic, cervical, and skin cancers, show evidence of field cancerization, where histologically normal tissue near a tumor contains genetic alterations. These mutations can provide signals that a malignancy is present. Early detection is important for lung cancers, 90% of which are NSCLC, because symptoms usually do not appear until the cancers are advanced and untreatable. Difficulty of detection may be the reason why lung cancer is the leading cause of cancer death in the United States, with more than 159,000 people dying from the disease each year. Studies such as Kadara’s might be able to change this, but larger studies are necessary. “We’re just beginning to understand the relevance of airway field cancerization to lung cancer detection and development of treatment and prevention strategies,” said Kadara.