CD274 and head and neck squamous cell carcinoma: However, while we did not observe any reduction in Kv1.3 activity in HNSCC circulating T cells, there was a profound suppression of this channel activity/expression in TILs, particularly those in close proximity with cancer cells, (Chimote et al., 2018; Newton et al., 2020) where the levels of PD-L1 are higher than in circulation.