Analysis of transcription factor OCT.1, OCT.2 and BOB.1 expression using tissue arrays in classical Hodgkin's lymphoma

Abstract

Hodgkin's lymphoma can be considered in most cases a B-cell lymphoma due to the presence of potentially functional immunoglobulin (Ig) gene rearrangements in the neoplastic cells. In contrast to lymphocytepredominant Hodgkin's lymphoma, Hodgkin/Reed-Sternberg (HRS) cells from classical Hodgkin's lymphoma have low frequency of B-cell marker expression and lack Ig light and Ig heavy messenger RNA. Recent studies have shown transcription machinery deficiency in Hodgkin's lymphoma caused by an absence of the transcription factors OCT.1, OCT.2 and/or BOB.1. By using the tissue microarray technique, we have performed an immunohistochemical study of OCT.1, OCT.2 and BOB.1 in 325 classical Hodgkin's lymphoma cases. The results have been correlated with the expression of the B-cell markers CD20, CD79a, B-cell-specific activator protein (BSAP) and MUM.1, the presence of Epstein-Barr virus and the histological subtype. The percentage of CD20 and CD79a positivity was low (18 and 18%, respectively), whereas MUM.1 and BSAP were positive in the majority of cases. Considering the positive cases with independence of the intensity of staining, 62% of them expressed OCT.2, 59% OCT.1 and 37% BOB.1. Nevertheless, when we considered only the strongly positive cases, the results were similar to those previously described by others. No statistical association was found between the transcription factor expression, histological subtype and Epstein-Barr virus presence. To our knowledge, this is the largest series of classical Hodgkin's lymphoma cases in which the expression of transcription factors has been studied. We have found a notorious percentage of cases displaying weak positivity for OCT.2 and BOB.1 factors in HRS cells. We propose that other mechanisms different from the absence of transcription factors OCT.2 and BOB.1 might be involved in the control of Ig transcription and B lineage in classical Hodgkin's lymphoma.

A clinicopathological study of B-cell differentiation markers and transcription factors in classical Hodgkin's lymphoma: a potential prognostic role of MUM1/IRF4

“…There is variation in the expression of these transcription factors reported in the literature due to small number of cases studied and/or to differences in immunohistochemical methods used. 9,10,22,23 We found a significant positive correlation between OCT.2 and CD79a expression (p=0.026), suggesting the existence of a common B-cell lineage down-regulating factor in H/RS cells. The latter observation was also made by Garcia-Cosio M et al 10 However, we did not find an association between BOB.1 and CD79a in our series.…”

“…9,10,22,23 We found a significant positive correlation between OCT.2 and CD79a expression (p=0.026), suggesting the existence of a common B-cell lineage down-regulating factor in H/RS cells. The latter observation was also made by Garcia-Cosio M et al 10 However, we did not find an association between BOB.1 and CD79a in our series. This discrepancy could be explained by the fact that BOB.1 is a co-activator of immunoglobulin gene transcription and is mainly involved, as indicated by gene knock-out data, in the late steps of B-cell differentiation.…”

“…In the present study we analyzed the CD79a/ BCL6/MUM1 B-cell differentiation immunophenotypes and the B-cell transcription factors BOB.1/OCT.2 in H/RS cells in 107 cases of CHL aiming to elucidate the histogenesis of CHL and correlate the pattern of expression of these markers with clinical and laboratory characteristics and the patients' outcome. Most previous studies [8][9][10][11][12][13]22 have shown a variety of results regarding the expression of all these markers and furthermore their clinical significance is not clear.…”

Lymphocyte-rich classical Hodgkin's lymphoma: distinctive tumor and microenvironment markers

“…On the basis of these categories, three tissue microarray blocks were constructed using a Tissue Arrayer Device (Beecher Instrument, Silver Spring, MD, USA), as described earlier. 4 All the tissue microarray block sections were immunostained with a panel of antibodies against CD30 (CON6D/B9, CNIO Monoclonal Antibody Unit, Madrid, Spain), CD20 (L26, DAKO, Glostrup, Denmark), CD15 (153A/D6, CNIO Monoclonal Antibody Unit), OCT.1 (12F11, Santa Cruz Biotechnology, Santa Cruz, CA, USA), OCT.2 (C-20 polyclonal, Santa Cruz Biotechnology), BOB.1 (polyclonal, Santa Cruz Biotechnology), bcl-6 (GI191E/ A8, CNIO Monoclonal Antibody Unit), PAX-5 (polyclonal, Santa Cruz Biotechnology), GCET-1 (341B/C1, CNIO Monoclonal Antibody Unit), KLHL6 (92C/D9, CNIO Monoclonal Antibody Unit), MUM-1 (ICSAT/M-17, Santa Cruz Biotechnology), C-REL (B-6, Santa Cruz Biotechnology), REL-B (polyclonal, Santa Cruz Biotechnology), TRAF-1 (H-3, Santa Cruz Biotechnology), p-50 (polyclonal, Gene Tex, San Antonio, TX, USA), IgD (polyclonal, DAKO), BLIMP-1 (195G/G5, CNIO Monoclonal Antibody Unit), CD38 (VS38, DAKO), CD3 (polyclonal, DAKO), CD57 (B321/NK-1, Abcam, Cambridge, UK), PD-1 (NAT105, Abcam 5 ), CD10 (56C6; Novocastra, Newcastle-upon-Tyne, UK), and CXCL13 (53610, R&D Systems, Minneapolis, MN, USA), using heatinduced epitope retrieval, as described earlier. Nonisotopic in situ hybridization for the Epstein-Barr virus (EBV) early RNA (EBER) was carried out using a fluorescein-conjugated PNA probe (DAKO) and an anti-FITC antibody (clone DAK-FITC4, DAKO), following the manufacturer's recommendations.…”

Aberrant T-cell antigen expression in classical Hodgkin lymphoma is associated with decreased event-free survival and overall survival

“…CD8) in our study is in agreement with the previously published data. 25 HRS cells are characterized by constant, albeit weak expression of PAX-5 protein, 44,45 but otherwise repressed the B-cell program. TCA expression on HRS cells may be consequent to critically low levels of PAX-5, because repression of PAX-5 has been shown to convert mature B cells into functional T lymphocytes.…”