Breast implant-associated, ALK-negative, T-cell, anaplastic, large-cell lymphoma: establishment and characterization of a model cell line (TLBR-1) for this newly emerging clinical entity.

[BACKGROUND] Primary lymphomas of the breast are very rare (0.2-1.5% of breast malignancies) and the vast majority (95%) are of B-cell origin. Recently, 40 cases of clinically indolent anaplastic large-cell kinase (ALK)-negative, T-cell, anaplastic, non-Hodgkin lymphomas (T-ALCL) have been reported worldwide.

[METHODS] A tumor biopsy specimen from a patient in this series was obtained for characterization. By using a human stromal feeder layer and IL-2, a novel cell line, TLBR-1, was established from this biopsy and investigated by using cytogenetics and various biomolecular methods.

[RESULTS] Immunoperoxidase staining of the tumor biopsy showed a CD30/CD8/CD4 coexpressing T-cell population that was epithelial membrane antigen (EMA)(+) and perforin(+) . Multiplex polymerase chain reaction (PCR) of TCRγ genes showed monoclonality that suggested a T-cell origin, yet pan-T markers CD2/5/7, anaplastic large-cell kinase (ALK)-1, pancytokeratins, CD20, CD56, and Epstein-Barr virus (EBV) by in situ hybridization (ISH) were negative. TLBR-1 is IL-2 dependent, has a relatively long doubling time (55 hours), and displays different cellular shapes in culture. Cytogenetic analysis of tumor and TLBR-1 cells confirmed a highly anaplastic cell population with a modal number of 47 chromosomes lacking t(2;5). PCR screens for EBV and human T-lymphotropic virus types 1 and 2 (HTLV-1/2) were negative. Fluorescence-activated cell-sorting (FACS) analysis showed strong positivity for CD4/8, CD30, CD71, and CD26 expression, and antigen presentation (HLA-DR(+) CD80(+) CD86(+) ), IL-2 signaling (CD25(+) CD122(+) ), and NK (CD56(+) ) markers, and Western blots demonstrated strong Notch1 expression. Severe combined immunodeficiency (SCID) mouse TLBR-1 heterotransplants recapitulated the histology and marker characteristics of the original tumor.

[CONCLUSIONS] TLBR-1, a novel ALK-negative, T-cell, anaplastic, large-cell lymphoma, closely resembles the original biopsy and represents an important tool for studying this newly recognized disease entity.