Oct2 and Bob1 are sensitive and specific markers in lineage determination of B cell lymphomas with no expression of conventional B cell markers.
OBJECTIVE
Rare cases of B cell lymphomas do not express conventional B cell markers (CD20, CD79a and PAX5), and these types of lymphomas include anaplastic lymphoma kinase (ALK)-positive large B cell lymphoma, plasmablastic lymphoma, primary effusion lymphoma and the solid variant of primary effusion lymphoma, extracavitary human herpesvirus 8 (HHV8)-positive large B cell lymphoma. Establishing accurate diagnoses of these B cell lymphomas can be challenging, and often requires a large panel of immunohistochemical stains, molecular assays and cytogenetic studies. B cell-specific transcription factors, Oct2 and Bob1, have been shown to be expressed consistently in most, if not all, B cell lymphomas, and therefore we investigated the utility of Oct2 and Bob1 immunohistochemistry in lineage determination of the aforementioned B cell lymphomas.


RESULTS
We selected 34 cases of previously diagnosed B cell lymphomas with no or weak expression of CD20, CD79a and PAX5. Oct2 and Bob1 were positive in 74% (25 of 34) and 85% (29 of 34) of the cases, respectively. When we combined the results of these two immunostains, 94% (32 of 34) cases expressed at least one of these two markers. We also included 51 control cases of non-B cell neoplasms, and none of them expressed either Oct2 or Bob1.


CONCLUSIONS
Oct2 and Bob1 are very reliable in determining B cell lineage in the absence of expression of other pan-B cell markers, and it should provide great diagnostic benefit to include them both in a panel of immunohistochemistry to assess undifferentiated malignant neoplasms.
Department of Pathology, University of Colorado Denver, Aurora, CO, USA.
Liqun
L
Yin
Department of Hematopathology, MD Anderson Cancer Center, Houston, TX, USA.
Jie
J
Xu
Department of Pathology, Peking University Health Science Center, Beijing, China.
Min
M
Li
Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.
Vishnu
V
Reddy
Department of Pathology, Zhejiang Wujing General Hospital, Zhejiang, China.
Quan
Q
Zhou
Department of Pathology, Guangdong Wujing General Hospital, Guangdong, China.
Huanxin
H
Liu
Department of Pathology, City of Hope National Medical Center, Duarte, CA, USA.
Peiguo
P
Chu
Department of Pathology, University of New Mexico, Albuquerque, NM, USA.
Qianyun
Q
Zhang
Department of Pathology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Qin
Q
Huang
Department of Pathology, Peking University Health Science Center, Beijing, China.
Zifen
Z
Gao
Department of Pathology, Children's Hospital Colorado, Aurora, CO, USA.
Xiayuan
X
Liang
Department of Pathology, University of California San Diego, La Jolla, CA, USA.
Huan-You
HY
Wang
Department of Pathology, University of Colorado Denver, Aurora, CO, USA. zenggang.pan@ucdenver.edu.
Zenggang
Z
Pan
D014408:Biomarkers, Tumor / Q000032:analysis*; D019070:Cell Lineage; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis*; D027701:Organic Cation Transport Proteins / Q000032:analysis / Q000096:biosynthesis*; D000075102:Organic Cation Transporter 2; D012680:Sensitivity and Specificity; D015534:Trans-Activators / Q000032:analysis / Q000096:biosynthesis*
D014408:Biomarkers, Tumor; D027701:Organic Cation Transport Proteins; D000075102:Organic Cation Transporter 2; C091546:POU2AF1 protein, human; C491013:SLC22A2 protein, human; D015534:Trans-Activators
B cell lymphoma; B cell markers; Bob1; Oct2; lineage determination