ATM kinase regulates tumor immunoreactions in lymphocyte-predominant breast cancer through modulation of NKG2D ligand and TNF cytokines on tumor cells

To explore impact of Ataxia telangiectasia mutated (ATM) kinase on immunoreactions in lymphocyte-predominant breast cancer (LPBC), particularly its role in triple negative breast cancer (TNBC), 194 cases of LPBC were identified with pertinent clinical information retrieved. The expressions of ATM, activated ATM (P-ATM), Fas ligand (FASL), tumor necrosis factor-related apoptosis-induced ligand (TRAIL), major histocompatibility complex class I chain-related protein A (MICA), CD8, and Forkhead box P3 (FOXP3) were assessed by immunohistochemically. We found that ATM expressed on tumor cells was correlated with upregulated expression of P-ATM and MICA ( P < 0.05), down-regulated expression of FASL and TRAIL ( P < 0.01), and decreased Ki-67 tumor labeling ( P < 0.05). However, within the TNBC group, only a negative correlation with FASL expression was found ( P = 0.001). ATM and MICA expressions were significantly down -regulated in TNBC ( P < 0.01) compared to non-TNBC, while TRAIL was significantly upregulated ( P < 0.01). Tregs were increased in TNBC ( P < 0.05), with CD8 + TILs decreased ( P < 0.01). Ki-67 index was higher in TNBC than in non-TNBC ( P < 0.01). ATM may play an important role in immunoreaction of LPBC, probably through upregulation of MICA and down-regulation of FASL and TRAIL. The down-regulated ATM expression in TNBC might be responsible for impaired tumor immunoactivity, rapid tumor growth, and aggressive clinical course.