Differential expression of PDL-1 between primary and recurrent/metastatic head and neck squamous cell carcinoma. Analysis of concordance and factors impacting on variations.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: Identify all the mentioned drugs in the given text. Text may or may not contain drug. If they contain more than 1 drug, use ";" as delimiter and join them. ### Input: Differential expression of PDL-1 between primary and recurrent/metastatic head and neck squamous cell carcinoma. Analysis of concordance and factors impacting on variations. ### Output: 