(A) Long-range PCR primer sequences and their positions on the exons of nucleophosmin gene and ALK gene exons involved in the NPM-ALK gene fusion. (B) RT-PCR primer sequences in relation to the fusion transcript. Primers P1 and P2 designed by Orscheschek et al is nested by primers M1 and M2 designed by Morris et al yielding a 177-bp product.