Substantial proportions of identical β-chain T-cell receptor transcripts are present in epithelial ovarian carcinoma tumors

To determine whether clonally expanded T cells are present in tumor specimens from patients with epithelial ovarian carcinoma (EOC) we amplified by the non-palindromic adaptor PCR (NPA-PCR) or by Vβ-specific PCR β-chain T-cell receptor (TCR) transcripts from these tumor specimens. The amplified transcripts were cloned and sequenced. Sequence analysis revealed the presence of substantial proportions of multiple identical copies of β-chain TCR transcripts, suggesting the presence of clonal expansions of T cells in these patients, which were statistically significant by the binomial distribution in seven of nine patients. Independent amplification in separate experiments of β-chain TCR transcripts from one patient by either NPA-PCR or by Vβ-specific PCR, followed by cloning and sequencing, revealed identical clonal expansions irrespectively of the amplification method used. Multiple identical copies of β-chain TCR transcripts can be derived only by specific antigen-driven proliferation and clonal expansion of the T-cell clones which recognize these antigens. Because of the very large size of the TCR repertoire, the probability of finding by chance multiple identical copies of these transcripts within an independent sample of T cells is negligible. These results demonstrate that T cells infiltrating solid tumor specimens or malignant ascites of patients with EOC contain monoclonal/oligoclonal populations of T cells.