Quantities of CD3+, CD8+ and CD56+ lymphocytes decline in breast cancer recurrences while CD4+ remain similar

Much is known about tumor infiltrating lymphocytes (Tils) in primary breast cancer, as this has been the focus of much research in recent years, but regarding recurrent breast cancer, only few studies have been done. Our aim was to compare the quantities of Tils in primary breast carcinomas and their corresponding recurrences and to analyze the differences in the tumor Tils compositions in correlations with recurrence-free times and the clinicopathology of the tumor.

One hundred thirty-seven breast cancer patients self-paired for primary- tumor-recurrence were divided into three groups based on the length of the recurrence-free interval. H&E-staining and immunohistochemical staining with antiCD3, antiCD4, antiCD8 and antiCD56 were performed. Differences in Tils between primaries and recurrences, between the recurrence-free interval groups, and between different clinicopathologic parameters were statistically analyzed.

Fewer stromal CD3+, CD8+ and CD56+ lymphocytes were found at recurrences compared to the primaries. No significant change in the percentage of CD4+ stromal lymphocytes. ER-negative primaries, PR-negative or HER2-positive tumors had more Tils in some subgroups. Ductal primaries had more Tils than lobular primaries and G3 tumors had more Tils than lower-grade tumors. The corresponding differences at recurrences could either not be detected or they were reversed. The fastest recurring group had generally more Tils than the slower groups.

CD4+ cell numbers did not decline from primary to recurrence in contrast to all other subclasses of lymphocytes. The proportion of CD4+ cells was higher in recurrences than in primaries. Tumors with a higher grade and proliferation rate had higher percentages of Tils. HER2+ and hormone receptor negative tumors tended to have higher Tils scores. In recurrences these differences were not seen or they were reversed.