For this reason, in recurrent, progressive, or metastastic patients, the NCCN guidelines recommend testing for mismatch repair system proteins (MMR), microsatellite instability, PD-L1 (positive for an immunohistochemical combined positive score, CPS ≥ 1), and comprehensive molecular profiling, including tumor mutation burden (TMB), HER2, NTRK, and RET analysis to select patients for immunotherapy and/or pan-tumor targeted drugs [272,604,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,636,637,638]. The gene discussed is RET; the disease is neoplasm.