Origin of the translocated segment of the 14q+ marker in non-Burkitt lymphomas.

The cytogenetic findings by G-banding in two histiocytic lymphomas are described. Both tumors had a stemline with a 14q+ marker. The origin of the extra segment on No. 14 was determined, and it was different in the two cases. These observations, and those from non-Burkitt lymphomas with 14q+ markers reported in the literature, indicate an inconsistent pattern for the origin of the extra material on No. 14. The only feature in common for all cases is instability of the distal region of the long arm of No. 14, and liability of this region to be involved in structural rearrangements, particularly translocations.