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Open Access Research

Immunophenotypic features and t(14;18) (q32;q21) translocation of Chinese follicular lymphomas helps to distinguish subgroups

Fen Zhang1, Li-Xu Yan1, Su-Xia Lin2, Zi-Yin Ye3, Heng-Guo Zhuang1, Jing-Ping Yun2, Han-Liang Lin3, Dong-Lan Luo1, Fang-Ping Xu1, Xin-Lan Luo1, Jie Cheng1, Ke-Ping Zhang1 and Yan-Hui Liu1*

Author affiliations

1 Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou 510080, China

2 Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, China

3 Department of Pathology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510060, China

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Citation and License

Diagnostic Pathology 2013, 8:154  doi:10.1186/1746-1596-8-154

Published: 18 September 2013

Abstract

Background

The revised 2008 World Health Organization classification maintains a histological grading system (grades 1–3) for follicular lymphoma (FL). The value of grading FL has been debated. This study will yield deeper insights into the morphologic, immunophenotypic characterization and t(14;18) translocation in FL and explore their significance of diagnosis of Chinese FL subgroups.

Methods

We retrospectively reviewed the FL diagnoses according to the 2008 WHO classification in all diagnostic specimens from a multicentric cohort of 122 Chinese patients. Upon review, 115 cases proved to be truly FL. CD10, BCL6, MUM1, BCL2 and t(14;18) (q32;q21) translocation were detected by Envision immunostaining technique and fluorescence in situ hybridization.

Results

FL1 has larger proportion of follicular pattern (93.0%) than that of FL2 (73.7%, P = 0.036), FL3B (63.6%, P = 0.003) and FL3A (77.4%, P = 0.053), although the last P value was more than 0.05 (Pearson’s chi-squared test). Areas of DLBCL were present in 25.8% (8/31) of FL3A and more frequent in FL3B (59.1%, 13/22; P = 0.015). The positivity of CD10 and BCL2 in FL1-2 were significantly higher than those in FL3 (P < 0.001, P = 0.043, respectively). The positivity of MUM1 in FL1-2 was significantly lower than that in FL3 (10.2% vs. 51.0%; P < 0.001). Furthermore the positivity of MUM1 in FL3A was significantly lower than that in FL3B (37.9% vs. 68.2%; P = 0.032). The positivity of t(14;18) was higher in FL1-2 than in FL3 (73.5% vs. 35.6%, P < 0.001), and was higher in FL3A than in FL3B (51.9% vs. 11.1%, P = 0.005). t(14;18) was significantly correlated with CD10+ (R = 0.453, P < 0.001) and MUM1+ (R = -0.482, P < 0.001).

Conclusions

FL1 and FL2 were immunophenotypically and genomically similar, while FL3A and FL3B were partly immunophenotypically similar but morphologically, genomically distinct. FL3A was genomically closer to FL1-2, whereas FL3A was genomically closer DLBCL. Thus we hypothesize that FL may in fact be a heterogeneous indolent lymphoma encompassing entities with distinct molecular pathogenesis and genetic characteristics. Immunohistochemical and genetic characterization helps to distinguish subgroups of FLs.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1334018129864616 webcite.

Keywords:
Follicular lymphoma; CD10; BCL6; MUM1; BCL2; Immunophenotype; t(14;18) (q32;q21) translocation