Novel immunotherapeutic options for refractory metastatic cancer patients include adoptive cell therapies such as tumor infiltrating lymphocytes (TILs). This study characterizes the clinicopathologic findings in a cohort of TIL specimens.
Patients with metastatic malignancy who were eligible had TILs from their metastases grown and expanded and then sent to pathology.
A total of 11 TIL specimens (10 melanoma, 1 adenocarcinoma) from patients enrolled in an experimental clinical trial were reviewed. All specimens showed more than 200 lymphoid cells, stained positive for lymphoid markers confirming an activated cytotoxic T-cell immunophenotype, and morphologically showed an intermediate-sized population with immature chromatin and frequent mitoses. Six cases (55%) showed large cells with nucleomegaly and prominent nucleoli.
This report is the first describing cytopathologic findings of autologous TIL therapy including adequacy guidelines and expected cytomorphologic and immunophenotypic findings. To meet this novel clinical demand, a predefined cytology protocol to rapidly process and interpret these specimens needs to be established.

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