Is the Tumor Infiltrating Natural Killer Cell (NK-TILs) Count in Infiltrating Ductal Carcinoma of Breast Prognostically Significant?

Purpose: The aim of this study was to investigate the prognostic significance of the CD56+NK-TIL countin infiltrating ductal carcinoma (IDC) of breast. Material and
Methods: Immunohistochemistry (IHC) wasperformed using antibodies specific for CD56 on formalin-fixed and paraffin-embedded tissue sections of 175infiltrating ductal carcinomas (IDC) of breast. Distribution of intratumoral and stromal CD56+NK-TILs wasassessed semi-quantitatively.
Results: A low intratumoral CD56+count showed significant and inverse associationswith tumor grade, stage, and lymph node status, whereas it had significant and direct association with responseto treatment indicating good prognosis. These patients had better survival (χ2=4.80, p<0.05) and 0.52 foldlower death rate (HR=0.52, 95% CI=0.28-0.93) as compared to patients with high CD56+ intratumoral count.The association of survival was insignificant with low CD56 stromal count as compared to high CD56 stromalcount (χ2=1.60, p>0.05).
Conclusion: To conclude, although NK-TIL count appeared as a significant predictorof prognosis, it alone may not be sufficient for predicting the outcome considering the fact that there exists acrosstalk between NK-TILs and the other immune infiltrating TILs.