Abstract: Objective To assess the prognostic value of CD20+ tumor-infiltrating lymphocytes (TILs) in early-stage breast cancer.
Methods Paraffin sections were collected from 130 cases of stage I-III breast cancer undergoing surgery between January, 2000
and December, 2002 in our hospital. Immunohistochemistry was used to analyze mesenchymal CD20+ TILs infiltration in the
tumor and evaluate its association with the density of CD4+ and CD8+ TILs. The association of CD20+ TILs was evaluated with
the histopathologic features, overall survival (OS), distant disease-free survival (DDFS), and disease-free survival (DFS) of the
patients. Results Aggregations of CD20+ lymphocytes were observed in 37.69% (49/130) of the cases. CD3+ T cells were found to
aggregate around CD20+ B cell aggregations to form lymphoid follicle-like structures. The aggregations of CD20+ TILs were
positively correlated with the densities of mesenchymal CD8 + and CD4 + TILs. Overall, CD20 + TIL aggregations were not
significantly correlated with the outcomes of the patients, but multivariate COX regressions suggested that CD20 + TIL
aggregations were positively correlated with DDFS (HR=0.251, 95% CI=0.071-0.894, P=0.033) and OS (HR=0.325, 95% CI=
0.103-1.028, P=0.056) in hormone receptor-negative patients but not in the positive patients. Further analysis suggested that
post-operative adjuvant endocrine therapy significantly improved the OS of patients positive for hormone receptors without
CD20+ TIL aggregations (P=0.001). Conclusion The long-term therapeutic effects of adjuvant endocrine therapy are correlated
with CD20+ TIL aggregations to affect prognostic value of CD20+ TIL aggregations in early-stage breast cancer patients.