The ALK/NPM1 DNA-FISH Probe is designed to detect the translocation between the ALK gene located at 2p23 and the NPM1 gene located at 5q35, using fluorescence in situ hybridization (FISH); the translocation between the ALK and NPM1 gene is designated as t(2;5)(p23;q35).  By conventional cytogenetics, the translocation occurs in up to 50% of anaplastic large cell lymphoma (ALCL) cases.^[1]  As assessed by immunohistochemistry, expression of the fusion protein ALK/NPM1 that is generated by t(2;5), occurs more frequently in childhood ALCL with an occurance rate of 83% versus adult ALCL which has an occurance rate of 31%.^[1,2]  The presence of t(2;5)(p23;q35) carries a better overall prognosis for ALCL patients.^[1]