CD117 expression in diffuse large B‐cell lymphomas: Fact or fiction?

Abstract

CD117 (KIT) is expressed in a variety of hematopoietic neoplasms but there are a paucity of data regarding its expression in diffuse large B-cell lymphomas (DLBCL). The purpose of the present paper was to describe the authors' experience of two CD117+ DLBCL (one of follicle center-cell origin and one nasal Epstein-Barr virus (EBV)- plasmablastic lymphoma associated with lytic bone lesions), as determined by tissue immunohistochemistry and flow cytometry. The CD117 expression in DLBCL was further evaluated using tissue microarrays and seven additional plasmablastic lymphomas, using two commercially available anti-CD117 antibodies (Ab-1, Oncogene and A4502, DakoCytomation). Membranous +/- cytoplasmic staining was seen with Ab-1 in 24/65 (37%) DLBCL, including 21/56 microarray DLBCL, two index cases, and 1/7 additional plasmablastic lymphomas, with persistent staining in 13% of microarray DLBCL despite preincubation with KIT peptide. However, A4502 had only membranous staining of the index cases and one additional EBV- plasmablastic lymphoma with medullary disease. The present study suggests that (i) CD117 expression can be detected sporadically in DLBCL of follicle center-cell origin and a subset of plasmablastic lymphomas; (ii) staining for CD117 might help in identifying EBV- plasmablastic lymphomas associated with bone marrow involvement; and (iii) CD117 antibodies should be carefully validated prior to use, because non-specific staining, as observed with Ab-1, could lead to false-positive results.

Microrna expression distinguishes between germinal center B cell‐like and activated B cell‐like subtypes of diffuse large B cell lymphoma

“…We found no evidence of expression of ckit in any of the cases (data not shown). It might be tempting to believe therefore that miR-221 suppresses expression of c-kit in DLBCL and FCL, however evidence implies that mRNA expression levels, in DLBCL at least, are not elevated to the extent found in other hematological malignancies, 25 suggesting that this gene is not a significant target for miR-221 in these lymphomas. High miR-221 expression levels have also been reported in thyroid carcinoma 23 and glioblastoma.…”

CD117 expression in gammopathies is associated with an altered maturation of the myeloid and lymphoid hematopoietic cell compartments and favorable disease features

“…[2][3][4] Noteworthy, aberrant CD117 expression has sporadically been reported in patients with B-cell non-Hodgkin´s lymphoma, but occurs in about 30% of all multiple myeloma (MM) patients. [5][6][7] Interestingly, CD117 expression by (mono)clonal plasma cells confers a favorable prognosis in multiple myeloma, albeit ckit has been associated with oncogenic transformation in other malignancies such as gastrointestinal stromal tumor and mastocytosis, in which it may represent an important target molecule for specific therapies (e.g. imatinib).…”

CD117 (KIT) is a useful marker in the diagnosis of plasmablastic plasma cell myeloma

“…10 On the other hand, very few PBLs have been reported to express this protein. 1,11 Additionally, it has been shown that phenotypic transformation occurs from B cell to plasma cell at the plasmablast stage. 12 A change in CD117 expression from negative to positive is a significant marker for this phenotypic transformation, and can differentiate a PBL plasmablast and a PPCM plasmablast when present.…”