Selective Accumulation of T Cells According to T-Cell Receptor Vβ Gene Usage in Skin Cancer

Abstract

To investigate whether specific T-cell populations are overrepresented in tumor-infiltrating lymphocytes (TIL) in skin cancer, we determined the T-cell receptor (TCR) diversity in biopsy specimens of basal cell carcinoma and squamous cell carcinoma. Immunostaining of tissue sections indicated that the majority of T cells expressed alpha beta TCRs. To assess diversity of the TCR beta chain, RNA was isolated directly from the tumor specimens and peripheral blood mononuclear cells (PBMC) from the same patient, cDNA was synthesized, and variable (V) beta chain gene usage was determined by the polymerase chain reaction (PCR). In each basal cell (n = 11) and squamous cell (n = 7) carcinoma studied, several V beta families were overrepresented in TIL versus PBMC, in that they accounted for greater than 5% of the repertoire in TIL and were at least 2% higher in TIL than in PBMC. The predominant V beta gene segments overrepresented in TIL generally differed from individual to individual. Simultaneous comparison of the V beta repertoire of TIL to that of uninvolved skin and PBMC from the same individual revealed preferential expression of V beta families within the TIL in three of five basal cell and four of four squamous cell carcinomas. Again, the predominant V beta s differed from individual to individual. Comparison of the TCR repertoire in uninvolved skin versus PBMC did indicate that some V beta families were overexpressed in the resident T-cell compartment in skin, although the overrepresented families were not constant from individual to individual. These data indicate the selective concentration of T cells bearing specific alpha beta TCRs in the local immune response to basal cell and squamous cell carcinomas.