**Crizotinib: A Targeted Therapy for ALK and ROS1-Positive Cancers**

**Definition:**  

Crizotinib is an oral small-molecule tyrosine kinase inhibitor (TKI) that targets anaplastic lymphoma kinase (ALK), ROS1, and MET mutations. It is specifically designed to treat cancers driven by these genetic alterations.

**Function:**  

Crizotinib works by inhibiting the activity of ALK, ROS1, and MET proteins, which are often overactive in certain cancers. By blocking these signaling pathways, it prevents cancer cell growth and survival, offering a targeted and effective treatment option.

**Applications:**  

Crizotinib is primarily used for the treatment of ALK-positive or ROS1-positive non-small cell lung cancer (NSCLC). It is approved

for both first-line and advanced-stage treatment, providing significant clinical benefits for patients with these specific genetic profiles. Its precision targeting makes it a cornerstone of personalized cancer therapy.