CD274 and squamous cell carcinoma: Atezolizumab has proved to induce PD-L1 internalization in PD-L1 positive cell lines, SK-MES, PC-9 and Calu-1 (lung cancers), MDA-MB-231 (triple negative breast cancer), MC-38 (murine colon adenocarcinoma), A431 (epidermoid carcinoma) and PD-L1 transfected CHO-K1 (Chinese hamster ovary).