RESUMO
This study was initiated to test the validity of in situ hybridization [ISH] for kappa/lambda light chain mRNA restriction in the diagnosis of FL and compare its value with that of Bcl-2 oncoprotein immunodetection. This work comprised formalin fixed paraffin embedded tissues from 36 lymph node biopsies including 31 cases morphologically consistent with FL and five cases of reactive follicular hyperplasia [RFH] taken as control. Thirty out of 31 FL cases showed a restriction to either kappa or lambda light chain mRNA. Sixteen cases showed kappa restriction, whereas lambda restriction was seen in 14 cases. All lymph nodes with RFH demonstrated a strong hybridization signal with both kappa and lambda oligonucleotide probes. BCL-2 oncoprotein was detected in neoplastic follicles in 20 out of 31 FL cases and was negative in germinal centers of all RFH cases