%0 Journal Article %T Disease progression after R-CHOP treatment associated with the loss of CD20 antigen expression %A Bellesso %A Marcelo %A Xavier %A Flavia Dias %A Costa %A Renata Oliveira %A Pereira %A Juliana %A Siqueira %A Sheila Aparecida Coelho %A Chamone %A Dalton Alencar Fischer %J Revista Brasileira de Hematologia e Hemoterapia %D 2011 %I Sociedade Brasileira de Hematologia e Hemoterapia %R 10.5581/1516-8484.20110036 %X a case of a follicular lymphoma transformed into a cd20+ is described which progressed with the loss of cd20 expression after 8 cycles of r-chop. this phenomenon is not a rare event and has shown poor prognosis. our purposes are to describe this event and suggest biopsy in relapsed or progressive disease. %K lymphoma %K large b-cell %K diffuse %K disease progression %K immunotherapy. %U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1516-84842011000200014&lng=en&nrm=iso&tlng=en