Phenotypic Differences of CD103⁺ Tissue-Resident Memory T Cells Associated with Various Cancers

Background/Aims: The presence and clinical importance of tissue-resident memory T (T-RM) cells have been recently described in association with various cancer types. However, the frequency and the traditional naive-effector-memory phenotypic characteristics of T-RM cells are largely unknown. Methods: We analyzed single-cell populations of colorectal cancer (CC, n = 18), stomach cancer (SC, n = 13), renal cell carcinoma (RCC, n = 19), and breast cancer (BC, n = 16) by dissociation of tumor tissue with collagenase/hyaluronidase. We investigated populations of naive, effector, and memory T and T-RM cells by flow cytometry. Results: Among CD8(-) cells, CC was associated with a significantly higher proportion of CD103(+) T cells than other tumor types (p < 0.001). Among CD8(+) cells, CC and SC were associated with higher CD103(+) T-cell proportions than RCC and BC (p < 0.001). Significantly more CD8(+) than CD8(-) cells expressed CD103 (p < 0.001). In association with SC, RCC, and BC, CD8(+) T cells had a similar T-cell phenotype composition pattern: fewer effector T cells and more memory-type T cells among CD103(+) cells compared with CD103(-) cells (p < 0.05). Tumors with higher proportion of CD103(+) cells had no specific clinicopathologic characteristics than those with lower proportion of CD103(+) cells. Conclusion: T-RM cell abundance and phenotypes varied among CC, SC, RCC, and BC. Further studies regarding the functional differences of T-RM associated with various tumors are warranted.