Transformation of B cell lymphoma to histiocytic sarcoma: somatic mutations of PAX-5 gene with loss of expression cannot explain transdifferentiation

• DOI: 10.1007/s12308-009-0031-2
• Publication Date: 2009-05-08T11:30:10Z
• Authors: Assia Bassarova; Gunhild Trøen; Alexander Fosså; Ida Munster Ikonomou; Klaus Beiske; Jahn M. Nesland; Jan Delabie
• Keywords: 03 medical and health sciences; Fuel Technology; 0302 clinical medicine; Chemistry(all); Chemical Engineering(all); Energy Engineering and Power Technology; Original Article; Physics and Astronomy(all); Pollution

Transdifferentiation of B cell lymphoma of germinal center cell origin to histiocytic sarcoma has recently been described but is a rare occurrence. The cause for loss of B cell differentiation in these lymphomas is unknown. We investigated whether somatic hypermutation of the PAX-5 gene, a transcription factor that is important for maintaining B cell identity and is frequently mutated in B cell lymphomas of germinal center cell origin, might be a cause for loss of PAX-5 expression and thus B cell phenotype. However, no somatic hypermutation of the PAX-5 gene was detected in the two cases we studied. The molecular basis for transdifferentiation of B cell lymphoma to histiocytic sarcoma remains therefore unresolved.