CD274 and head and neck squamous cell carcinoma: However, a recent comprehensive systematic review of Prince et al. [65] revealed an excellent concordance between 28-8, 22C3, and SP263 clones in assessing PD-L1 expression in cancer cells among the common cancer subtypes (e.g., NSCLC, HNSCC, and urothelial carcinoma); in contrast, SP142 clone stained substantially fewer cancer cells than the three other clones in these cancers.