The absence of the NPM-ALK fusion gene was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) in 8 cases and by fluorescence in situ hybridization (FISH) analysis in a further 2 cases.     ///    "These results suggest that lymphomas carrying variants of the NPM-ALK fusion protein can be detected by immunostaining for ALK and NPM and also that they can be grouped with classical t(2;5)-positive tumors as a single entity (ALK-positive lymphoma or ""ALKoma"") that shows a better prognosis than ALK-negative anaplastic large-cell lymphoma.. "    ///    " The tumor cells in ALK-positive lymphoma (""ALKoma"") usually express the product of the NPM-ALK chimeric gene, generated by the t(2;5) chromosomal translocation. "    ///    "In each case, ALK staining was restricted to the cytoplasm and the N-terminus of NPM to the nucleus (contrasting with lymphomas expressing NPM-ALK in which cytoplasmic as well as nuclear labeling is seen). "    ///    "However, 10% to 20% of ALK-positive lymphomas express ALK fusion protein(s) other than NPM-ALK, and in this report, we describe the immunohistologic and clinicopathologic features of 15 such cases. "    ///    Lymphomas expressing ALK fusion protein(s) other than NPM-ALK.. 