Cytogenetic abnormalities in the leukemic phase of non-Hodgkin lymphoma

We have carried out chromosome analysis in a series of 16 non-Hodgkin Lymphoma (NHL) cases in leukemic phase. The diagnoses in these patients based on histology and immunologic markers were as follows: follicular lymphoma (FL), 3 cases; mantle cell lymphoma (Mc), 4 cases; lymphoplasmacytic lymphoma (LPL), 8 cases, and large cell lymphoma, 1 case. We have shown that the t(14;18), t(11;14), and trisomy 12 retained their subtype association with FL, Mc, and LPL, respectively, as in their nonleukemic counterparts with one case of FL showing t(1;19)(q23;p13). Among the four LPL cases without trisomy 12, one case each showed t(12;14)(q13;q32), trisomy 14, t(1;3)(p34;q21), and del(3)(q21). The t(1;19) and t(12;14) may represent rare events in FL and LPL, respectively, and may be uniquely associated with the leukemic phase. The breakpoint 14q32 was the most common single breakpoint involved, sometimes involving both chromosome 14 homologues depicting its association with primary and secondary genetic events in the disease progression. In addition to the main abnormalities, we have shown additional complex abnormalities in 14 of 16 cases. Among these, chromosome 3 was the most commonly involved, affecting the short or long arm or the whole chromosome; 5 of the 16 cases involved breakpoint 3q21. The high incidence of additional abnormalities in these NHL in leukemic phase suggest an association with the development of leukemia and progression of the disease.