Serotonin receptor 3A expression in normal and neoplastic B cells.

Chromosome 11q21-qter is a very gene-rich region and is often targeted by genomic aberrations in a variety of human cancers, including B cell lymphoid neoplasms. In order to identify genes which could be deregulated in diffuse large B cell lymphomas (DLBCL), we analyzed the expression levels of genes mapped on chromosome 11q21-qter across a series of publicly available DLBCL expression data sets. We identified HTR3A, the gene coding for 5-hydroxytryptamine receptor 3A, as the most frequently differentially expressed. Since HTR3A expression had not been previously characterized in normal and neoplastic B cells, we evaluated its expression by real-time PCR and by immunohistochemistry. The gene is expressed by B cells and it seems to be regulated during the mature B cell differentiation, being overexpressed during the germinal center phase. Lymphomas derived from germinal center B cells maintain the expression, with the level of expression varying among different patients.