To characterize molecular markers for risk of adult T-cell leukemia/lymphoma (ATL), whose incidence rate differs greatly across geographic areas, we propose to examine the prevalence and level of viral and host immune response markers as well as the protein expression pattern of 57 subjects who subsequently developed ATL and 171 matched control subjects who participated in various prospective studies of carriers of human T-lymphotropic virus type I (HTLV-I). Informative markers to be studied include provirus load, HTLV-I antibody titer, anti-Tax protein, clonality of HTLV-I infected lymphocytes (viral markers), total immunoglobulin E (IgE), C-reactive protein (CRP), neopterin, soluble CD30, soluble interleukin-2 receptor (sIL2-R), EBV antibody profile (host immune markers), and proteomics. These markers were selected based on the measurability on the majority of specimens, availability of validated assays, relevance to the biology of T-cell malignancies, and has been used in a cross-sectional comparison of HTLV-I carriers and non-carriers from Japan and the Caribbean. We will utilize central laboratory and validated, standard assays for all specimens. The results, unlinked to personal identifiers, will be analyzed using generalized estimating equation. The findings will further our understanding of the etiology of ATL, and of differences in natural history of HTLV-I infection across geographic areas.

While pursuing the same theme of trying to identify host and viral markers associated with ATL, the unique aspect of this proposal is to pool ATL cases, an extremely rare malignancy, from multiple epidemiologic studies through international collaboration, in order to achieve adequate statistical power and to perform valid comparison of tumor characteristics across geographic areas.