T-Cell Receptor (Tcr) Dna Deep Sequencing To Evaluate Clonalit) Of Titmor-Infiltrating Lymphocytes (Tils) In Early Stage Breast Cancer Patients (Pts) Receiving Preoperative Cryoablation (Cryo) And/Or Ipilinournab (Ipi).

3021 Background: In mice, cryo combined with cytotoxic T lymphocyte antigen 4 (CTLA-4) blockade increases antigen-specific TILs, generating a synergistic rejection of secondary tumors. In humans, breast cancer antigens are shared across pts in low frequency and are incompletely characterized. Thus, to evaluate for antigen-specific TILs in pts receiving cryo and/or the anti-CTLA-4 antibody, ipi, we employed deep sequencing of TCR CDR3 region DNA, which provides a quantitative measurement of the frequency of individual T cell clones, each putatively reactive to a unique antigen. Methods: 19 pts were treated with cryo (7 pts), single-dose ipi at 10mg/kg (6 pts), or cryo+ipi (6 pts). Core biopsy (Bx) +/- cryo was performed 7-10 days prior to standard-of-care mastectomy and ipi was given 1-5 days before core Bx. From available specimens, DNA was sequenced using the immunoSEQ™ assay. Utilizing CDR3 sequence copy number, the frequency of each unique T cell clone was determined. Nonparametric analyses were conduc...