Early Rebiopsy to Identify Biomarkers of Tumor Cell Survival Following EGFR, ALK, ROS1 or BRAF TKI Therapy

This study takes early tumor biopsies and blood samples from people with advanced non-small cell lung cancer (NSCLC) that has a specific genetic driver mutation, to understand why some cancer cells survive targeted drug treatment — and how to overcome that resistance. **You may be eligible if...** - You are 18 or older with advanced (stage III or IV) lung cancer that has a specific targetable gene mutation (such as EGFR, ALK, ROS1, or BRAF) - You have not yet started treatment for your advanced or metastatic cancer - Your cancer is measurable on a scan and can be safely biopsied (for the biopsy group) - You are in reasonably good health (ECOG 0–2) **You may NOT be eligible if...** - You have a bleeding disorder that makes biopsy unsafe (for the biopsy group) - Your only accessible biopsy site carries unacceptable risk (for example, near the heart) - You plan to receive your ongoing care at a facility outside the University of Colorado Health System (for the blood-draw-only group) Talk to your doctor to see if this trial is right for you.