Background: Several lines of evidence indicate that a more favorable prognosis is correlated with the degree of lymphocyte infiltration within breast carcinomas. The characterization of these T-cell infiltrates appears necessary to explore the possible existence of an in situ immunologic response of the host against neoplastic cells. Previous studies have indeed suggested that the T-cell receptor (TCR) repertoire of tumor-infiltrating T-lymphocytes (TIL) should be restricted if they act specifically against tumor-related antigens.
Methods: To address this question, the expression of variable (V) region genes of the TCR-alpha and beta chains in intratumoral lymphocytes from five breast carcinoma biopsy specimens and one normal mammary gland specimen was analyzed using the polymerase chain reaction (PCR). The neoplastic samples included one medullary carcinoma and four ductal infiltrating carcinomas selected on the basis of a rich lymphoid stromal component. Primers specific for 18 different V alpha and 21 V beta families were used for PCR.
Results: In every case, TIL showed an unrestricted pattern of TCR V-region gene expression, similar to the repertoire observed in peripheral blood lymphocytes and in the normal breast tissue.
Conclusions: According to these nonquantitative PCR experiments, the apparent lack of selection of a limited number of T-cell specificities in the affected tissues does not favor the existence of an in vivo lymphoid recruitment based on TCR recognition of neoplastic antigenic determinants. Further studies, however, leading to an accurate quantification of immunologically relevant T-cell clones and including larger series of cases still are necessary before it will be possible to draw a final conclusion.