Abstract
The pathophysiological significance of tumor infiltrating lymphocytes remains controversial. To clarify their role, we performed clinicopathological analysis of CD8+ T cells in 131 cases of human colorectal cancer. CD8+ T cells were classified into three groups by their localization: (a) those infiltrated within cancer cell nests; (b) those distributed in the cancer stroma; and (c) those present along the invasive margin (tumor-host interface). Of these, CD8+ T cells within cancer cell nests were most significantly associated with a better survival of patients by both mono- and multivariate analyses. The impact on survival was similar to that of Dukes' staging. Granzyme B+ cytoplasmic granules were detected in lymphocytes within cancer cell nests, confirming their activated, cytotoxic phenotype. CD8 and Ki-67 double immunohistochemistry confirmed higher proliferative activity of CD8+ T cells within cancer cell nests. Our data suggested that human colorectal cancer tissue was infiltrated by various numbers of T cells that had cytotoxic phenotype, contributing to a better survival of patients. This infiltration of colorectal cancer cell nests by CD8+ T cells could be a novel prognostic factor.
Footnotes
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↵1 To whom requests for reprints should be addressed, at Department of Pathology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ward, Sendai 980-8575, Japan. Phone: 81-22-717-8049; Fax: 81-22-717-8053; E-mail: hohtani@patholo2.med.tohoku.ac.jp.
- Received June 3, 1998.
- Accepted July 13, 1998.
- ©1998 American Association for Cancer Research.
Volume 58, Issue 16
