This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunomodulator, Subject name: Pharmacology
Cizotinib is inhibitor of which receptor - 
Select and explain. 
A. Tyrosine kinase, B. VEGF receptor, C. TNF alpha receptor, D. PDGF receptor
A: Tyrosine kinase
Answer: A: Tyrosine kinase 
Explanation: Ans. is 'a' i.e., Tyrosine kinase Crizotinib* It is a small molecule multitargeted tyrosine kinase receptor inhibitor targeting ALK, MET, ROS1 kinases.* By inhibiting ALK tyrosine kinase activity, crizotinib inhibits cell proliferation, induces G1 - S phase cell cycle arrest and apoptosis.* It is approved for the first line in management of metastatic non-small cell lung cancer with an ALK mutation.* The most common adverse effects associated with crizotinib are vision disorder, diarrhea and edema.* It is also associated with QT prolongation and bradycardia* Tumors invariably acquire resistance after one year of treatment. Mechanism of resistance include mutations in ATP binding pocket of the tyrosine kinase domain of ALK.