Tumour infiltrating lymphocytes (TILs) in breast cancer during pregnancy

BackgroundTumour infiltrating lymphocytes (TILs) is one of the most exciting breast cancer biomarkers, yet no data is available on its prevalence in tumours diagnosed during pregnancy.MethodsWe evaluated the prevalence of TILs (stromal and intratumoural) in pregnant and non-pregnant young breast cancer patients.Results11/116 (9.6%) of the non-pregnant and 2/86 (2.3%) pregnant patients had TILs ≥ 50% (p < 0.001) with highest prevalence observed in triple negative tumours (p = 0.01).ConclusionsThis is the first report on TILs in tumours diagnosed during pregnancy. The low prevalence could reflect the state of low host immunity associated with pregnancy.