Serum thymidine kinase activity as a "real-time" clinical biomarker of tumor response to CDK4/6 inhibition in hormone receptor positive (HR+), HER2 negative (HER2-) metastatic breast cancer
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: Serum thymidine kinase activity as a "real-time" clinical biomarker of tumor response to CDK4/6 inhibition in hormone receptor positive (HR+), HER2 negative (HER2-) metastatic breast cancer ### Output: 