Researchers who have identified a gene linked to low-grade T cellleukemia said the discovery could have far-reaching implications forstimulating or inhibiting production of lymphocytes, which areresponsible for mediating the immune system.

The gene, TCL1, was identified after seven years by researchers atthe Jefferson Medical College in Philadelphia, the University ofAlabama at Birmingham, Toyama University in Japan and Raggio-Italgene SpA, a Italian biotechnology company in Pomezia.

The discovery is described in today's issue of the Proceedings of theNational Academy of Sciences (PNAS) and was discussed in lastThursday's edition of Cancer Research.

Giandomico Russo, head of molecular genetics at Raggio-Italgene,told BioWorld the TCL1 gene was found to be expressed inlymphocytes involved in low-grade leukemias, such asprolymphocytic leukemia and chronic lymphocytic leukemia as wellas adult T cell leukemia, which was thought to be caused by a virus.

Low-grade leukemias are chronic in their progression compared withhigh-grade leukemias, which are acute. The discovery of TCL1,Russo said, represents the first discovery of a gene specific to low-grade leukemia.

The PNAS paper is titled "Identification of the TCL1 gene involvedin T cell malignancies." In it, the researchers stated, "The TCL1 genesequence, which to our knowledge, shows no sequence homologieswith other human genes, is preferentially expressed early in T and Blymphocyte differentiation."

Russo said the identification of the gene, whose existence had beenpostulated for years, may represent the discovery of a whole newfamily of genes involved in both T cell and B cell malignancies.

Carlo Croce, director of the Jefferson Cancer Institute at JeffersonMedical College, told BioWorld, "TCL1 clearly might play a majorrole in lymphocyte proliferation and survival. If we can manipulateTCL1, we may be able to affect growth or survival of T cells and Bcells."

As a result, Croce added, while inhibiting TCL1 expression may beused to fight leukemia, the gene also may be targeted to stimulateproduction of T cells to bolster the immune system against otherdiseases, such as AIDS.

Another researcher on the project, Max Cooper, of the University ofAlabama, said the discovery is "very exciting because of itslymphocyte specificity and its early stage and early differentiationspecificity. We still don't know its function, but we think it likelywill play an important role."

The next step in the research, Croce said, will be to understand howthe TCL1 gene works. He said patents for the gene and its uses areshared by Jefferson Medical College and Raggio-Italgene. n

-- Charles Craig

(c) 1997 American Health Consultants. All rights reserved.