While ATM germline variant testing was not previously recommended by the European Society for Medical Oncology (ESMO) Precision Medicine Working Group as a common inclusion for clinical germline testing, it is now recommended for patients undergoing testing for actionable pathogenic variants in addition to seven ‘most actionable’ cancer-susceptibility genes (BRCA1, BRCA2, PALB2, MLH1, MSH2, MSH6, and RET) for which germline investigation is recommended—regardless of tumor type [43,44]. The gene discussed is RET; the disease is cancer.