Infiltration of CD8+ T cells in non-small cell lung cancer is associated with dedifferentiation of cancer cells, but not with prognosis

CD8(+) T cells infiltrating within cancer cell nests in human colorectal cancer were associated with a favorable patients' survival, suggesting the presence of anti-tumor immunity. The present study was designed to examine this concept in non-small cell lung cancer (NSCLC) by a retrospective analysis of 128 surgically resected cases. Immunohistochemical analysis showed that the number of CD8(+) T cells within cancer cell nests in NSCLC was related to the histological subtype (large cell carcinoma or squamous cell carcinoma > adenocarcinoma) and the degree of dedifferentiation (undifferentiated type > differentiated trpe). In contrast to colorectal cancer, the number of CD8(+) T cells in NSCLC had no statistically significant impact on the patients' survival. The present study demonstrated that the degree of infiltration of CD8(+) T cells within cancer cell nests is dependent on the dedifferentiation of cancer cells in NSCLC, which could be one of the important aspects for the study of tumor immunity. (C) 2000 Tohoku University Medical Press.