Cancer of the gastrointestinal tract results in a restricted T-cell repertoire dependent upon tumor differentiation.

We investigated the influence of tumor tissue differentiation on the diversity of TCR repertoire. CDR3 spectratypes of CD4(+) and CD8(+) T cell subsets were analyzed from 27 patients with gastrointestinal tract tumors exhibiting varying degrees of differentiation. A CDR3 spectratype complexity scoring system was used to quantify the diversity of TCR repertoire. Each patient was matched with an age-matched healthy group to control for age variability. Results show that the complexity scores (TCR repertoire diversity) have a significant correlation with the degree of tumor differentiation, which provides useful information for understanding immune response in cancer patients.