Immunoglobulin variable regions usage by B-lymphocytes infiltrating a human breast medullary carcinoma

Breast medullary carcinoma are heavily infiltrated by B-lymphocytes and ass ociated with a good prognosis despite their high histological grade. We inv estigated the Ig repertoire of B-lymphocytes infiltrating one such tumour. A single cell suspension was obtained from a tumor specimen by enzymatic di gestion. VH, V kappa, and V lambda regions were amplified by RT-PCR using m ixtures of primers optimized to maximize the diversity of the PCR products. They were then cloned and sequenced. Analysis of 9 VH, 5 V kappa, and 10 V lambda sequences using the Kabat database indicated that several VH and VL region subgroups (I, II and III) are expressed by B-lymphocytes infiltrati ng this tumor. The analysis of CDR3 regions also showed a variability, alth ough some VH and VL clones exhibited identical or nearly identical sequence s. Thus, the B-cell infiltration observed in this breast medullary carcinom a does not reflect a monoclonal proliferation and represents an oligoclonal or a polyclonal B-cell proliferation. (C) 1999 Elsevier Science B.V. All r ights reserved.