The cutaneous T-cell lymphomas (CTCL) are a group of diseases characterized by malignant proliferations of CD4 positive T-cells having monoclonally rearranged T-cell receptor (TCR) genes. A recent study using monoclonal antibodies to two TCR beta-chain variable (V) region gene products showed preferential expression of the V beta 8 gene product in these tumors. The finding of predominant usage of a single V beta gene would imply that selection by antigen is important in the etiology of these tumors. We have studied eight cases of cutaneous T-cell lymphoma and one cell line derived from a patient with mycosis fungoides/Sezary syndrome, using an extended panel of antibodies to V region gene products. Contrary to the previous report, in our study expression of the V beta 8 gene product by tumor cells was not observed in any of the cases of CTCL or in the tumor cell line studied; preferential use of any of the variable region genes recognized by the antibodies in the panel was not observed.