Date of Award


Document Type


Degree Name

Medical Doctor (MD)

First Advisor

Michael Girardi, MD

Second Advisor

Robert Tigelaar, MD

Third Advisor

David Leffell, MD


Title: ANALYSIS OF CD8 TUMOR INFILTRATING LYMPHOCYTES IN HUMAN CUTANEOUS SQUAMOUS CELL CARCINOMA Authors: Swapna Reddy, Scott J. Roberts, Renata Filler, Sumaira Aasi, David J. Leffell, Michael Girardi, Department of Dermatology, Yale University School of Medicine, New Haven, CT The specific aims of this project are (1) to examine the lymphocytic infiltrates of human cutaneous squamous cell carcinomas (SCC) of varying stages, (2) to isolate CD8 tumor infiltrating lymphocytes (TILs) from human cutaneous SCC in situ tumors and SCC tumors, and (3) to phenotype and characterize these CD8 TILs. The specific hypotheses of this project are that (1) the lymphocytic infiltrates of human early stage SCCs, SCCs in situ, differ from the infiltrates seen in SCCs (2) that a subset of CD8 TILs from human SCCs exhibit similar phenotypic patterns previously characterized CD8 TILs from murine SCCs. To accomplish these aims, we recruited patients with histopathologically diagnosed SCCs in situ and SCCs scheduled for excision by Mohs micrographic surgery. T-cells were isolated from tumors and analyzed by flow cytometry for expression of TCRβ, CD8, CD44, and CD62L (marker of central memory T-cells). CD8 TILs were then analyzed using RT-PCR for gene expression patterns noted in murine CD8 TILs: Tc17 phenotype (production of IL-17 and associated transcription factors), reduced cytotoxic capacity (expression of perforin, NKG2D, FasL), and regulatory potential (expression of IL-10). Lymphocytic infiltrates of SCCs in situ exhibited a smaller proportion of CD8 TILs and a smaller fraction of central memory CD8 TILs as compared to the infiltrates of SCCs. Compared to effector memory CD8 TILs, central memory CD8 TILs had an increased expression of IL-17 and IL-10 and mildly decreased expression of perforin. CD8 TILs isolated from SCCs of varying stages illustrate a dynamic adaptive immune response that changes with more advanced tumors. The increased production of IL-17 and IL-10 by central memory CD8 TILs in SCCs may contribute to tumor development as seen in previous murine models. However, in contrast to that seen in murine models, CD8 TILs from human cutaneous squamous cell carcinomas maintain some cytotoxic capacity even in more advanced tumors.


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