title: Disease progression after R-CHOP treatment associated with the loss of CD20 antigen expression.
abstract: 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.
authors.affiliation: Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, Instituto Octavio Frias, São Paulo, SP, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Bellesso
authors.forename: Flavia Dias
authors.initials: FD
authors.lastname: Xavier
authors.forename: Renata Oliveira
authors.initials: RO
authors.lastname: Costa
authors.forename: Juliana
authors.initials: J
authors.lastname: Pereira
authors.forename: Sheila Aparecida Coelho
authors.initials: SA
authors.lastname: Siqueira
authors.forename: Dalton Alencar Fischer
authors.initials: DA
authors.lastname: Chamone
keywords: Disease progression; Immunotherapy; Lymphoma, Large B-cell, diffuse