Gene May Hold Key to Reducing Spread of Oral Cancers

The spread of cancer cells in the tongue may be reduced if a gene that regulates cancer cell migration can be control­led, according to new re­search at the University of Il­linois at Chicago (UIC) Col­lege of Dentistry. Oral cancer is an undertreated and poorly understood disease, says Xiao­feng Charles Zhou, PhD, an assistant professor in the UIC Center for Molecular Biology of Oral Diseases and lead researcher of the study. More than 90% of oral cancers are squamous cell carcinomas that normally start on the gums, floor of the mouth, or tongue. About 30,000 Amer­icans are affected each year.
     While new cancers of all types have risen 8% in the last 5 years, oral cancer has increased 21%, according to the American Cancer Society. Tongue squamous cell carcinoma, one of the most frequent oral cancers, rose more than 37% in this period. Al­though overall cancer deaths decreased during this period, those due to oral cancer in­creased by 4% and those due to tongue squamous cell carcinoma by 10%.
     Improvements in patient survival require better understanding of tumor invasion and how cancer spreads, said Dr. Zhou, so that aggressive tumors can be detected early and targeted therapies can be developed. While researchers have tried to identify altered genes that contribute to the aggressive nature of tongue squamous cell carcinoma, most previous studies have focused on protein-encoding genes, stated Dr. Zhou. The new study ex­amines a noncoding gene called microRNA-138. Micro­RNAs are small, noncoding RNA molecules that control the expression of a target gene after the intermediary message for the gene has been transcribed into RNA, stated Dr. Zhou. Several microRNAs are believed to stimulate the spread of various types of cancer. The new study, he said, demonstrated that a reduced level of microRNA-138 is associated with enhanced ability of tongue squamous cell carcinoma cells to spread. “Our knowledge of genomic aberrations associated with noncoding genes and their contributions to cancer initiation and progression is relatively limited,” he said. The study is published in the August issue of the International Journal of Cancer.