Effect of neoadjuvant chemotherapy on tumor-infiltrating lymphocytes and PD-L1 expression in breast cancer and its clinical significance.

ABSTRACT:

Background

The effects of neoadjuvant chemotherapy on immune markers remain largely unknown. The specific aim of this study was to assess stromal tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) protein expression in a cohort of breast cancer patients treated with neoadjuvant chemotherapy.

Methods

Using quantitative immunofluorescence, we investigated stromal TILs and PD-L1 protein expression in pre-treatment? and residual breast cancer tissue from a Yale Cancer Center patient cohort of 58 patients diagnosed with breast cancer from 2003 to 2009 and treated with neoadjuvant chemotherapy. We compared the TIL count and PD-L1 status in paired pre-treatment and residual cancer tissues and correlated changes and baseline levels with survival.

Results

Of the 58 patients, 46 (79.3%) had hormone-positive and 34 (58.6%) had node-positive breast cancer. Eighty-six percent of residual cancer tissues had TIL infiltration and 17% had PD-L1 expression. There was a trend for higher TIL counts in postchemotherapy compared to prechemotherapy samples (p?=?0.09). Increase in TIL count was associated with longer 5-year recurrence-free survival (p?=?0.02, HR?=?3.9, 95% CI?=?1.179-15.39). PD-L1 expression (both stromal and tumor cells) was significantly lower in post-treatment samples (p?=?0.001). Change in PD-L1 expression after therapy or TILs and PD-L1 expression in the posttreatment samples did not correlate with survival.

Conclusions

Increase in stromal TILs in residual cancer compared to pretreatment tissue is associated with improved recurrence-free survival. Despite a trend for increasing TIL counts, PD-L1 expression decreased in residual disease compared to pretreatment samples.

SUBMITTER: Pelekanou V 

PROVIDER: S-EPMC5547502 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature