Gene behind aggressive lymphatic cancer identified

Only a single gene decides whether a rare form of cancer called thymoma, derived from the epithelial cells of the thymus, an organ critical to the lymphatic system where T-cells, or so-called "killer cells," mature, will be aggressive or non-aggressive, finds a new study.

Very little is known about the role of the gene mutation GTF2l in human tumours, but the scientists said almost all indolent (slow growing and non-aggressive) forms of thymoma they tested have the mutation.

"Indolent thymomas seldom become aggressive, so the discovery that a single gene can identify tumours that do not need aggressive care is an important development for our patients," said senior investigator Giuseppe Giaccone from Georgetown Lombardi Comprehensive Cancer Centre in the US.

"The study is important because it is highly unusual to find a single mutated gene that can define a class of tumours," he said.

"Usually a substantial number of genes are involved. In fact, we also found that the more aggressive thymomas express well known cancer genes found in other tumours - which might give us clues about novel treatment of these cancers," Giaccone explained.

The thymus is located in the chest behind the breastbone. Thymoma and a second type of cancer of the thymus called thymic carcinoma are rare.

Most of the diagnosed patients have surgery, but, depending on the presumed aggressiveness of the cancer, some patients will have radiation and/or chemotherapy in addition or instead of surgery.

"The use of these treatments in thymomas is controversial because we know some patients don't need aggressive therapy, but until now there's not been a clear way to know who those patients are," Giaccone said.

The findings appeared in the journal Nature Genetics.