For some diseases such as lung cancer with canonical driver alterations, detection of individual driver variants (e.g., EGFR, KRAS) can offer a measure of ctDNA shed [106,107], yet the same could be feasible in other tumor types such as pancreatic [108], prostate [109], bladder [110], breast [111], and colorectal [112] cancer. The gene discussed is EGFR; the disease is lung cancer.